GRAVELY ZT HD STEALTH 60 Service Manual

Service Manual Overview

The GRAVELY ZT HD STEALTH 60 service manual provides a comprehensive guide to the maintenance, inspection, troubleshooting, and repair of this heavy-duty zero-turn mower. It covers essential systems including drive hydraulics, engine integration, electrical controls, chassis and frame integrity, cutting deck alignment, and safety interlocks. The documentation is structured to support qualified technicians in diagnosing issues efficiently, implementing repairs correctly, and restoring the machine to optimal operating condition. It emphasizes standardized procedures, torque specifications, and recommended service intervals to extend the life of components and maintain peak performance in demanding environments. This overview serves as a roadmap to understanding the machine’s critical subsystems and the safe, methodical approach required for professional servicing.

The manual consolidates both routine maintenance tasks and situational repair workflows, enabling technicians to plan service events with clarity. It outlines the tools, accessories, and calibration checks needed for accurate work, while also outlining the expected results of each procedure. By detailing the sequence of steps and the rationale behind them, the manual helps technicians anticipate potential complications and apply correct corrective actions. This section is designed to be a quick reference for shop technicians as well as a detailed resource for in-depth servicing. Proper adherence to the procedures in this manual promotes reliability, safety, and consistent performance of the GRAVELY ZT HD STEALTH 60.

Purpose and scope

The purpose of this manual is to provide clear, technically accurate instructions for the maintenance, troubleshooting, repair, and calibration of the GRAVELY ZT HD STEALTH 60 zero-turn mower. It covers the complete lifecycle of service activities from routine preventive maintenance to complex sub-assembly repairs. The scope includes the engine, fuel system, electrical harness and control modules, hydraulic circuits, steering and drive motors, cutting deck mechanics, chassis, safety systems, and on-board diagnostics. While the manual aims to be comprehensive, it is intended for use by trained technicians who possess the appropriate tools and safety training to work on powered equipment. Adherence to the procedures ensures repair quality, safety, and machine longevity.

The document also addresses common failure modes, wear patterns, and performance degradation indicators. It provides diagnostic flowcharts, signal tests, and measurements that help identify root causes efficiently. In addition to troubleshooting, the manual prescribes preventive maintenance schedules aligned with operating hours and environmental conditions. The scope extends to component replacement guidelines, proper reassembly techniques, and post-repair verification to confirm that systems function within specification. This thorough approach supports consistent, repeatable results across service tasks.

Safety guidelines and symbols

Safety is the foundation of every maintenance operation described in this manual. Technicians must follow all applicable local and national safety regulations, wear appropriate personal protective equipment, and ensure the work area is secure before commencing any task. The manual details specific hazard symbols and their meanings, including electrical shock, hot surfaces, moving parts, and high-pressure fluid systems. It also outlines lockout/tagout procedures, safe lifting practices, and steps to prevent unintended machine startup during service. Understanding and respecting these guidelines reduces the risk of injury and equipment damage during maintenance activities.

Each procedure is accompanied by recommended safety precautions, required tools, and proper containment methods for lubricants, fuels, and hydraulic fluids. The document emphasizes verifying system depressurization and proper isolation of fluid lines before disassembly. It also instructs on testing and inspection after reassembly to ensure that safety interlocks, emergency stops, and operator controls respond correctly. By adhering to the safety guidelines and recognizing warning symbols, technicians can perform high-quality service while maintaining a safe working environment for themselves and others.

The Gravely ZT HD Stealth 60 is a heavy-duty zero-turn mower designed for demanding commercial and residential maintenance tasks. It features a robust chassis, a dual hydrostatic drive system, and a 60-inch cutting deck that delivers consistent, high-capacity performance across varied terrain. The drive system provides precise steering and smooth motor response, enabling effortless maneuvering around obstacles and tight yard spaces. Engine options typically align with robust, commercial-grade gasoline powerplants that deliver ample torque for extended cutting sessions. The machine utilizes a sealed, weather-resistant electrical system and simplified service access points to minimize downtime during routine maintenance.

Key specifications commonly associated with the ZT HD Stealth 60 include overall length and width that balance stability with manageable transport, and a high-capacity fuel tank designed for extended operation between fill-ups. Ground clearance is adjusted to accommodate a range of grass heights and terrain, reducing scalping and improving mowing efficiency. The cutting deck employs independent blade spindles and a landed, well-supported belt drive to maintain even blade speed and an even cut. A robust frame and reinforced mounting points are designed to withstand the rigors of daily use in commercial settings while preserving operator safety and reliability over time.

The model variants and compatibility details highlight differences in engine type, deck configuration, and optional accessories. Certain configurations may offer optional hydraulic deck lift, integrated tool racks, or upgraded seat suspensions to enhance operator comfort on longer shifts. It is essential to verify the exact model number, production year, and serial range when sourcing replacement parts or service manuals. Cross-reference with Gravely’s official parts catalogs to ensure compatibility of spindles, belts, pulleys, and hydros with your specific machine. Operators should also confirm compatibility with any aftermarket accessories, such as catcher systems or mulch kits, to ensure proper fitment and performance.

Pre operation inspection is the foundation of safe and reliable operation for the GRAVELY ZT HD STEALTH 60. Before engaging any cutting or mowing task, perform a thorough check of all critical systems and components. Inspect the engine for oil levels, fuel condition, and any signs of leaks or damage. Confirm that the battery connections are secure and free of corrosion. Examine the tires or tires and wheels for proper inflation, wear, and any cuts or bulges that could affect stability. Look over the belt guards, exhaust system, and chassis for cracks or loose hardware, tightening any fasteners to the manufacturer's specified torque. Ensure that all controls return to their neutral positions when released and that the parking brake engages securely. This initial inspection helps identify potential issues that could lead to equipment failure or unsafe operation during use.

Safety chain and blade guard checks require particular attention because they directly influence operator safety and machine performance. Start by confirming the safety chain is properly routed and tensioned according to the service manual, with no missing or damaged links. If the chain shows signs of excessive wear or elongation, replace it using the approved parts to maintain cutting efficiency and risk reduction. Inspect the blade guard assemblies for cracks, missing fasteners, or misalignment, and verify that the guards move freely without interference. Ensure the blades are sharp and balanced, and that the blade spindle and mounting hardware are secure. Check that the ignition key or start switch cannot be engaged unless the operator presence controls are functioning correctly, preventing accidental startup. Conduct a functional test of the blade engagement mechanism with the mower raised and the parking brake applied to confirm safe operation before proceeding to a full work cycle.

Lubrication and Maintenance Schedule

The Gravely ZT HD Stealth 60 requires a disciplined lubrication and maintenance routine to sustain optimal performance and extend the life of the drivetrain, deck drive, and steering system. Begin each use with a quick visual inspection to identify signs of wear, leaks, or loose fasteners, and note any unusual noises or performance changes. Use manufacturer-recommended lubricants and replacement parts, and always clean any debris from moving components before applying lubrication. Consistent lubrication reduces friction, minimizes heat buildup, and helps prevent wear on bearings, bushings, and linkages that are critical to smooth operation. Maintain a log of servicing to track intervals and ensure nothing is overlooked during busy mowing seasons.

Daily maintenance checklist involves a thorough wipe-down of exposed surfaces to remove grass clippings, dirt, and moisture that can accelerate corrosion. Check hydraulic hoses and fittings for signs of wear or leaking fluid, and verify that all shields and guards are securely in place. Inspect tire pressure and wheel lug tightness to ensure stable operation, and confirm that the cutting deck is leveled and free of debris before engaging the blades. Lubricate accessible grease fittings with manufacturer-approved grease, paying particular attention to pivot points, steering linkage, and implement drive components. This daily attention helps preserve performance and identifies potential issues before they escalate into costly repairs.

Lubrication points and intervals cover the essential bearing and pivot areas that require periodic oil or grease. Primary blade spindle bearings, drive belt idlers, and steering linkage tend to benefit from light lubrication after each use or every 8 hours of operation, depending on conditions. Use a high-quality lithium-based grease or the grade specified in the service manual for all fixed and rotating joints, and avoid over-lubricating, which can attract debris and create buildup. The hydraulic system should be checked for corrosion and small leaks, with lubrication of external components as directed by the manufacturer. For the mower deck, lubricate the height adjustment and deck hangers at intervals recommended, and never apply lubricant to belt surfaces or pulleys that could degrade belt traction or cause slippage. Adhering to these intervals maintains smooth deck movement and precise cutting height control.

During routine maintenance, inspect lubrication lines and seals for wear and replace any damaged components promptly. If a grease gun is used, purge the line to remove air and ensure consistent grease flow to all fittings. Replace any worn bushings or dry bearings with OEM parts to prevent noise, vibration, and misalignment that could affect cutting performance. Record the exact service dates, the part numbers of replaced components, and the type of lubricant used to establish a reliable maintenance history for future reference. Regular maintenance not only sustains peak mower performance but also helps preserve resale value and safety for the operator over the long term.

Engine and Fuel System

The GRAVELY ZT HD STEALTH 60 is designed with a robust powerplant that balances performance with reliability for demanding outdoor maintenance tasks. When evaluating engine specifications, verify the displacement, rated horsepower, compression ratio, and ignition type to ensure the unit meets the manufacturer's design parameters. Maintain a record of the engine model, serial number, and service intervals to track oil changes, filter replacements, and scheduled inspections. Understanding these specifications helps technicians diagnose issues more accurately and plan maintenance cycles around operating hours and load conditions. Always consult the operator’s manual for torque values, crankcase venting recommendations, and service bulletins that may impact performance or warranty coverage. Proper acclimation to ambient temperatures and altitude can also influence fuel and ignition tuning, so consider environmental factors during diagnostics and adjustments.

Fuel system integrity is crucial for dependable starts and consistent power delivery. Begin with a visual inspection of all hoses, clamps, and connections for signs of wear, cracking, or leaks. Check the fuel filter and replace it according to the maintenance schedule or sooner if fuel is contaminated or the system exhibits reduced flow. When inspecting the fuel pump, listen for abnormal whines or hesitations during priming, and verify pressure within the manufacturer's specified range using appropriate diagnostic tools. Maintain clean fuel within the recommended octane grade, and avoid ethanol concentrations that could lead to phase separation or varnish buildup in the carbureting or injection components. Ensure the fuel lines are secured away from hot exhaust areas and moving parts to prevent abrasion and potential ignition hazards.

When performing engine servicing, maintain clean working conditions to prevent dirt ingress into the intake, fuel, or lubrication systems. Use OEM filters and gaskets to preserve sealing integrity and to avoid improper fitment that could cause vacuum leaks or fuel leaks. During valve clearance checks, follow the prescribed lash specifications and adjust with the correct feeler gauges, re-torqueing fasteners to the recommended values to avoid timing or compression issues. After servicing, perform a base idle and warm-up procedure to verify smooth operation, ensuring there are no abnormal exhaust noises, misfires, or warning indicators illuminated on the operator interface. Document all service actions, including parts replaced and technician initials, to support warranty compliance and future troubleshooting.

For fuel system examination and servicing, proceed with a systematic approach: inspect, test, replace, and verify. Begin with the intake system for leaks and obstructions, then verify fuel delivery pressure and return flow, adjusting if permitted by the service literature. If fuel contamination is suspected, remove the tank and purge the system while installing a new filter and, if needed, a new fuel line. Recheck for leaks under pressurized conditions and conduct a functional test under load to confirm that the engine maintains steady RPMs and responds promptly to throttle input. Comprehensive testing should conclude with a road test or field test to ensure reliable operation under typical mowing or duty cycle conditions. Document results and any anomalies for ongoing maintenance planning.

Battery and charging system: The Gravely ZT HD Stealth 60 relies on a reliable 12-volt lead-acid or AGM battery to power starting and ancillary electrical functions. Begin by inspecting the battery case for cracks, swelling, or corrosion at the terminals, and verify that the battery is securely mounted to minimize vibration-induced damage. Use a multimeter to verify battery voltage; a healthy, fully charged battery should read approximately 12.6 to 12.8 volts when the engine is off. When the engine is running, a properly functioning charging system will maintain charging voltages in the range of 13.8 to 14.8 volts, indicating the alternator or charging regulator is applying correct output. If the battery voltage falls outside these ranges under normal operating conditions, perform a step-by-step check of the charging circuit, including fuses, wiring harness connectors, and the alternator belt tension, ensuring there are no slippage or grounding issues. Additionally, inspect the battery terminals and connectors for corrosion and clean them with a suitable terminal cleaner or a solution of baking soda and water, then apply a light coat of dielectric grease to prevent future oxidation.

Wiring diagrams and troubleshooting procedures: A thorough understanding of the wiring layout is essential when diagnosing electrical faults in the ZT HD Stealth 60. Begin by labeling harness connectors before disconnecting any components to maintain correct reassembly order, and refer to the factory wiring harness color codes to identify each circuit quickly. When diagnosing a no-crank condition or intermittent electrical failures, verify supply voltage to the starter solenoid, ignition switch, and keyless access system, checking for blown fuses, damaged insulation, or chafed wires that could cause short circuits under vibration. Use a digital multimeter to check continuity on suspect wires and inspect for high-resistance connections at bulkhead connectors, grounds, and grounding straps; poor grounds are a common source of electrical gremlins in lawn and garden equipment. For diagnostics related to accessories such as headlights, terminal indicators, or the instrument cluster, test each circuit individually with the wiring diagram in hand, and confirm that the control modules are receiving proper power, ground, and signal inputs. When repairing wiring, always employ heat-shrink tubing, weatherproof seals, and mechanical protection to withstand outdoor exposure and vibration, ensuring that all repairs are performable to OEM standards and that any splices are done with correct gauge wire and soldered or properly crimped with appropriate terminals. Finally, after completing any electrical work, perform a functional test that simulates normal operating conditions, including engine start, throttle control, and load application, to verify that all circuits operate correctly without triggering fault codes or nuisance warnings.

The steering and hydraulics system on the GRAVELY ZT HD STEALTH 60 is a critical pathway for precise control and safe operation. A correct understanding of steering linkage components, hydraulic lines, pumps, and reservoirs is essential for diagnosing issues, performing routine maintenance, and conducting effective field repairs. Begin with a thorough inspection of visible components, including tie rods, steering arms, hydraulic hoses, and the power-assist unit. Look for signs of wear, such as elongation, uneven play, corrosion, or leaks, and document any deviations from factory specifications for further corrective action. Maintaining clean connections and secure mounting hardware helps prevent unexpected steering loss and extends the life of the hydraulic system.

Steering linkage inspection requires a systematic approach to verify alignment, play, and movement without binding. Start by checking the steering wheel input to the intermediate linkage and ensure that the steering wheel returns to the center position smoothly after a turn. Measure the free play at the steering linkage joints with the wheels in a straight-ahead position, noting any excess play that exceeds manufacturer tolerances. Inspect the tie rods, ball joints, and pivot points for wear marks, corrosion, or damaged protective boots, and replace any compromised components promptly. A misaligned or worn linkage can cause drifting, reduced steering responsiveness, or unpredictable handling, especially at higher operating speeds.

Hydraulic system service and bleed procedures require careful preparation and adherence to proper sequence to avoid introducing air into the circuit or causing contamination. Begin by securing the machine on a level surface and engaging the parking brake, then identify the hydraulic reservoir fill cap and bleed ports according to the manual’s guidance. Check hydraulic fluid level with the system cool to ensure an accurate reading, and use only the recommended fluid type and viscosity as specified by Gravely to prevent compatibility issues. During bleeding, connect the appropriate return lines and follow the prescribed order to remove air from the circuit, paying close attention to any signs of air entrapment such as spongy steering feel or a soft pedal. After completing the bleed, recheck for leaks at all fittings, tighten as necessary, and operate the steering through its full range of motion to confirm smooth, consistent response without hesitation or dead spots.

Additional maintenance considerations for the steering and hydraulics involve routine inspection schedules and contamination control. Regularly replace hydraulic filters per the service interval, and keep the reservoir cap sealed to minimize dust intrusion. Use clean, sealed containers when servicing fluid and avoid exposing the hydraulic fluid to contaminants from the environment. Monitor hydraulic hose integrity—look for cracking, swelling, or cut insulation that could lead to leakage or pressure loss. When replacing components, torque fasteners to the manufacturer’s specifications and verify that hoses are routed away from hot surfaces, sharp edges, or moving parts that could abrade lines over time. By combining careful inspection, proper bleeding, and disciplined maintenance, you ensure precise steering performance and reliable hydraulic operation under all working conditions.

The Gravely ZT HD Stealth 60 uses a robust transaxle system designed to provide reliable power delivery and smooth operation under demanding lawn care tasks. Understanding the transaxle layout and service points is essential for maintaining optimal performance and extending the life of the drive components. Begin with a careful inspection of the transaxle housing for any signs of oil leakage, unusual wear, or physical damage. Confirm that all mounting bolts are present and torqued to the specified values, and verify that the mounting brackets and supports are secure. A clean, dry exterior allows for easier identification of leaks and early signs of seal wear during routine maintenance checks.

Inside the transaxle, the gear set, differential, and drive belt work together to transfer engine power to the output shafts. The differential provides power to each rear wheel while allowing for smooth turning, which reduces tire scrubbing and wear. Regular checks of the differential case for cracks or seepage, along with ensuring proper lubricant level and condition, help prevent costly failures. When inspecting the transaxle, also examine the drive belt path for proper routing and tension, as incorrect belt alignment can cause accelerated wear and reduced traction. The transaxle vent should be clear of obstructions to prevent pressure build-up that could force oil past seals or cause gasket leaks.

Drive belt inspection and replacement is a critical maintenance task that directly affects drive performance, acceleration, and overall control of the machine. Start by removing the belt access cover to gain a clear view of the belt condition and the pulley surfaces. Look for signs of cracking, fraying, glazing, or missing teeth on the belt and inspect the pulleys for grooves, chips, or foreign debris that could impede belt operation. When replacing the belt, select a belt that matches the original OEM specifications for Pinion-to-Lin or complementary drive ratios, and ensure correct belt tension as per the service data. After installation, rotate the pulley manually to confirm smooth belt movement without binding, and listen for any unusual noise that could indicate misalignment or bearing issues in the transaxle assembly.

In addition to belt and differential checks, practice routine lubrication of accessible bearings and moving joints as recommended by Gravely’s service data. Use only the specified lubricants and quantities to avoid overfilling or under-lubrication, which can cause overheating or reduced efficiency. When performing belt maintenance, inspect the belt tensioner and tensioner pulley for wear and proper operation, replacing worn components to preserve belt life. Reassemble all covers and shielding securely, and perform a function test on a level surface to verify that drive traction and braking respond consistently across different load conditions. Document all findings, replacement parts, and torque values in the maintenance log to support future service intervals and warranty compliance.

Cutting Deck and Mower Assembly

The cutting deck is the heart of the mower’s performance, and proper alignment and conditioning are essential for achieving a clean, even cut and prolonged component life. Begin with a thorough inspection of the deck mounting points, spindle housings, and belt paths to identify any signs of wear, deformation, or looseness. Check the deck for any bending or cracking, and verify that all fasteners are tightened to the manufacturer’s specified torque values. When the machine is on a level surface, measure the deck height at multiple points to confirm uniformity; deviations can indicate misalignment that will affect cut quality and cause uneven wear on blades and spindles. Maintain clean deck surfaces, removing grass buildup after each operation to prevent corrosion and imbalance as the deck spins at high RPMs. Regularly inspect the lift mechanism and anti-sway components to ensure consistent deck position during operation.

Deck alignment and leveling are critical to achieving an even cut across the full width of the mower. Begin by placing the machine on a level surface and removing any obstructing debris from the underside. Use a straightedge or a deck alignment tool to verify that the cutting edges of the blades are parallel to the ground and that the deck plane is level from left to right and front to back. If misalignment is detected, adjust the leveling screws or spacers according to the service values listed in the maintenance data, ensuring that changes are made in small increments and rechecked after each adjustment. After adjustments, rotate the blades by hand to confirm free movement with no rubbing or interference. Document the alignment measurements and keep a record for future maintenance cycles to track any gradual changes in deck geometry.

Blade maintenance and replacement procedures are essential for maintaining cut quality, safety, and engine efficiency. Begin with a safety check: disconnect power, remove the ignition key, and ensure the blade assembly cannot rotate. Inspect each blade for nicks, cracks, and excessive wear along the cutting edge and trailing edge, replacing blades that show signs of damage or dullness beyond recommended service limits. When replacing blades, use the correct mounting hardware and apply a torque specification to the blade bolts as provided by the manufacturer. Balance the blades after installation by spinning the spindle assembly by hand and listening for unusual vibrations, and by checking for equal blade weight distribution using a blade balancing tool. Maintain a careful record of blade part numbers, replacement dates, and any observed wear patterns to anticipate future maintenance intervals and prevent unexpected downtime during peak mowing seasons.

Routine maintenance extends the life of the mower and ensures consistent performance. Always inspect the belt drive system for proper tension and alignment, replacing any worn or cracked belts promptly. Lubricate the moving deck components per the maintenance schedule, focusing on pivot points, lift arms, and spindle housings with manufacturer-approved lubricants. Use only genuine replacement parts to preserve the integrity of the deck assembly and guarantee compatibility with the cutting height and anti-rotation features. When performing any disassembly or reassembly, follow the documented torque values and sequence to avoid warping the deck or creating misalignment. A proactive maintenance routine, performed at regular intervals, will keep the GRAVELY ZT HD STEALTH 60 mower operating at peak efficiency and deliver consistently professional-looking results.

The cooling and ventilation system of the GRAVELY ZT HD STEALTH 60 is engineered to maintain optimal operating temperatures under demanding mowing and load conditions. Proper function hinges on a clean radiator, unobstructed intake and exhaust paths, and adequate coolant levels. Start with a visual inspection of the cooling fins and shrouding for bent fins, crushed louvers, or debris buildup that could impede airflow. Measure coolant level when the engine is cold, and verify that the mixture ratio matches the manufacturer’s specification to prevent overheating or freeze damage. Regularly inspect the coolant reservoir and hoses for signs of leaks, cracks, or softening, and replace any compromised components to maintain consistent cooling performance. This section outlines best practices for maintaining airflow and eliminating heat soak that can degrade engine longevity and performance.

Debris accumulation is the primary enemy of effective cooling in this mower. A daily or weekly cleaning routine should include removing grass clippings, leaves, and dust from around the radiator, grill, and cooling shroud. Use a low-pressure air stream or a soft brush to dislodge debris without bending cooling fins. Pay particular attention to the area behind the tractor’s intake and beneath the mower deck, where clippings can travel and become compacted. If you notice persistent debris buildup after cleaning, inspect the undercarriage and radiator housing for any structural gaps that could funnel more material into the cooling area, and seal or repair as needed. Maintaining a clear airflow path ensures the radiator can efficiently reject heat, especially during high-load mowing or in hot climates.

Airflow optimization also depends on proper shroud and fan operation. Confirm that the cooling fan spins freely without rubbing or unusual noise, and check for a secure mounting that won’t allow vibration-induced damage. If the shroud is cracked or bent, replace it to restore the designed airflow pattern. Ensure that the radiator fins are free of corrosion and deformation; use a fin comb or professional service tools to straighten damaged fins when possible. Maintain unobstructed inlets and outlets around the cooling system, including verifying that protective grills are intact and free of obstruction. When the mower is operating, observe the external temperatures of the engine compartment; excessive heat at idle or during light loads can indicate insufficient airflow or low coolant level that requires attention beyond routine cleaning.

To maximize cooling efficiency, schedule a periodic coolant system service aligned with the manufacturer’s recommended intervals. This includes draining old coolant, flushing the system if specified, and refilling with the correct coolant type and concentrate, ensuring no air pockets remain in the passages. Replace thermally sensitive components like temperature sensors and radiator caps according to service life recommendations to prevent pressure loss or inaccurate temperature readings. Consider upgrading to higher-capacity or more efficient cooling components if operating in extreme heat or under continuous high-load conditions is common for your location. Proper coolant maintenance, combined with proactive debris management, will help extend engine life and maintain consistent performance throughout the mowing season.

In environments with heavy dust, sand, or agricultural particulates, implement additional protective strategies such as pre-cleaning air intakes with screens or guards designed to reduce ingress. Periodically inspect hoses and clamps for signs of aging, bulging, or leaks, replacing any suspect components to preserve coolant integrity and prevent overheating. Document all maintenance actions with dates and observed conditions so that trends can be identified early and addressed before function is compromised. By adhering to these practices, operators will sustain reliable engine cooling, reduce the likelihood of heat-related downtime, and maintain the GRAVELY ZT HD STEALTH 60’s performance across a broad range of mowing conditions.

Diagnostics and troubleshooting for the GRAVELY ZT HD STEALTH 60 require a methodical approach to identify root causes and implement effective repairs. Begin with a calm, thorough inspection of the mower’s powertrain, electrical system, and safety interlocks. Visually inspect belts, pulleys, and blades for wear or damage, and check tire pressure and suspension components to ensure proper traction and stability during operation. Use a diagnostic mindset to separate symptoms from underlying faults, documenting each finding for reference. When possible, perform functional tests under load to verify that observed issues persist beyond idle or non-operating conditions. Maintain a clean workspace and use proper safety procedures to prevent injuries during inspection and testing.

Common issues and solutions cover a wide range of systems, from electronics to hydraulics and mechanical wear. For power loss or limited cooler temperature performance, verify fuel quality, air intake cleanliness, and engine cleanliness, then inspect spark plugs or ignition modules as needed. If the mower exhibits uneven mowing or blade vibration, inspect blade balance, spindle bearings, and belt alignment, replacing worn components as required. Electrical gremlins such as intermittent startup or warning lights can often be traced to loose connections, corroded terminals, or blown fuses; clean grounds, reseat connectors, and replace fuse blocks if necessary. For charging or battery-related problems, test the alternator output under load and ensure cabling is intact and free of damage. Address hydraulic or drive system concerns by checking fluid levels, reservoir vents, hoses for leaks, and pump performance, ensuring that filters are clean and properly seated. A systematic approach to these common issues minimizes downtime and extends the life of the machine.

Error codes interpretation and steps require careful reference to the machine’s diagnostic outputs and service indicators. Begin by verifying the code against the manufacturer’s list and noting any accompanying symptoms or recent maintenance actions. Clear codes only after confirming the underlying cause, as simply resetting a code without remediation may recur. For many codes, a step-by-step procedure includes verifying connections, performing power resets, and measuring sensor voltages with a multimeter to confirm normal ranges. If a code points to a safety interlock, inspect the related switch, wiring, and mechanical linkage to ensure proper engagement and safety of the operator. Document resolved codes and the corrective actions taken, then run a full system test to ensure the fault does not reappear under normal operating conditions. When in doubt, consult the service manual's wiring diagrams and torque specifications to prevent misadjustments during repairs.

Additional best practices include maintaining a log of maintenance intervals, keeping spare parts on hand for common wear items such as belts, blades, and filters, and performing preventive diagnostics during seasonal storage or commissioning. Use proper protective equipment and ensure the mower is completely powered down before disconnecting components or opening access panels. Calibrate sensors after any component replacement to restore accurate readings, and perform a road test or field test to confirm that all subsystems operate harmoniously. By following these guidelines, technicians can efficiently diagnose faults, perform safe repairs, and restore the GRAVELY ZT HD STEALTH 60 to full productive service while maintaining safety and compliance standards.

Safe disassembly practices are the foundation of a successful service procedure for the Gravely ZT HD Stealth 60. Begin by disconnecting the battery and removing the key to prevent accidental starting during work. Wear appropriate personal protective equipment, including gloves and eye protection, to shield against sharp edges and debris. Establish a clean, organized workspace with clearly labeled containers for fasteners and small parts to prevent loss or misplacement. Before any disassembly, consult the equipment’s service markings and verification tools to confirm model compatibility and to identify any safety interlocks that must be disabled in a controlled manner. Use proper lifting techniques and, when necessary, a helper or lifting device to avoid personal injury and equipment damage. Document each step with notes or photographs to aid accurate reassembly and future maintenance.

During the disassembly process, sequence is critical to avoid damaging components and to preserve the integrity of the drive system, hydraulic lines, and electrical harnesses. Remove exterior body panels with a minimal set of tools, keeping track of fastener length and location. Disconnect electrical connectors with a gentle rocking motion to prevent pinched wires, and label each connector to its corresponding harness or circuit. When draining fluids such as engine oil, hydraulic fluid, and fuel, perform this in a controlled environment with appropriate containment to prevent environmental contamination. Protect hose assemblies from kinking by laying them in a natural route and avoiding sharp bends. Inspect gaskets, seals, and O-rings for wear and replace them as needed to ensure a proper seal upon reassembly. Maintain a logical order for reassembly to reduce the risk of missing fasteners or misrouted hoses.

Orderly reassembly process begins by confirming all removed parts are accounted for and visually inspected for damage. Replace any worn or damaged components using manufacturer-approved parts, and verify compatibility by cross-referencing serial numbers and service manuals. Reconnect electrical harnesses with care, ensuring each plug mates fully and locks into place. Reinstall fluid lines ensuring correct routing away from hot surfaces and moving parts, using new clamps or fittings where specified. Refill fluids to the recommended levels and torque fasteners to the specified values in a gradual, crisscross pattern to promote even pressure and sealing. After completion, perform a systems check, starting with safety interlocks and then verifying engine and drive functions, noting any abnormal readings. Finally, document the service work, including part numbers, lot numbers if applicable, and the date of service to support future maintenance and warranty compliance.

The GRAVELY ZT HD STEALTH 60 requires precise handling when performing component replacement to ensure safety and optimal performance. Begin by powering down the machine, removing the key, and disconnecting the battery to prevent any accidental engagement of electrical systems during service. Inspect the drive belts, pulleys, and mandrel assemblies for wear, cracks, or misalignment before removing any parts. When replacing components, use manufacturer-approved parts that meet OEM specifications, and verify compatibility with the model year and serial number. Document each part replacement with the date, part numbers, and operating hours to maintain a thorough maintenance history for future reference.

For belt and pulley replacements, release tension carefully using the appropriate tensioning tool or method specified by Gravely, then remove the belt without forcing components. Install the new belt following the correct routing diagram and ensure the belt sits evenly within the pulley grooves. After installation, reapply tension to the belt to the recommended specification, and rotate the drive system by hand to confirm smooth operation without binding. Replace any protective covers or shields that were removed during the procedure, and recheck all fasteners for proper torque once the system is powered back up and tested at low idle.

When servicing the cutting system or chassis components, remove safety interlocks and disconnect any wiring harnesses with care to avoid bending terminals. If a bearing or bushing replacement is required, press or drift the component evenly to avoid damaging the housing, and inspect the shaft for runout or scoring. Apply a light coat of manufacturer-approved lubricant where specified, and reinstall components in the exact orientation they were removed to maintain balance and performance. After reassembly, perform a functional test at low speed to verify smooth operation, followed by a full system test under working load to confirm there are no abnormal noises or vibrations.

Torque specs and fastener guidelines are critical to prevent over-tightening or under-tightening which can lead to component failure. Always use the correct size and grade fasteners and follow the torque values provided by Gravely for each fastener location. When working with aluminum housings, apply fasteners in a crisscross pattern to distribute load evenly and avoid distortion. Use a calibrated torque wrench and confirm readings at the specified temperature range, as cold or hot conditions can affect fastener torque. After completing a repair, recheck all critical joints and connections, including electrical harnesses, fuel lines, and control linkages, to ensure the machine remains safe and reliable during operation.

For component replacement procedures, prepare a clean work area with a clear path for parts and tools. Label and organize removed components to aid in accurate reassembly, and photograph critical assemblies before disassembly to guide reassembly if needed. If a replaced part is found to be defective or not within tolerance, replace it with an OEM-quality component and reverify the system after installation. Always follow the specific service manual illustrations for torque sequences and clearance specifications, and never substitute non-OEM parts that could compromise safety or performance. Conclude by conducting a comprehensive diagnostic check, including electrical continuity and safety interlocks, to ensure the machine is ready for field operation.

Calibration and performance verification for the GRAVELY ZT HD STEALTH 60 require a systematic approach to ensure the mower operates at peak efficiency and with reliable safety margins. Begin with a thorough pre-check of all fasteners, gauges, and linkage connections to verify that no components were disturbed during maintenance. Confirm that the engine is at the correct operating temperature and that the fuel system is free of air, leaks, or contamination. Use the manufacturer-recommended torque specs and alignment procedures when reassembling steering pivots, control arms, and drive linkages to avoid uneven wear and unpredictable handling. Document any deviations observed during this initial inspection so they can be addressed before proceeding with functional tests.

Operational checks after service focus on verifying control responsiveness, safety interlocks, and drive system integrity. Engage and release the parking brake to confirm engagement cues and brake resistance are within the specified range, and inspect that the blade engagement system yields clean, immediate engagement without grinding or slipping. Test the operator presence controls and seat switch with the engine running to ensure proper shutoff behavior when the operator leaves the seat. Inspect the hour meter, speed control, and pedal engagement to confirm linear and predictable response across the full speed range. If any anomaly is detected, isolate the fault to the affected subsystem and perform targeted diagnostics before returning the mower to service.

Performance benchmarks and testing establish quantifiable targets for load handling, cutting efficiency, and fuel economy. Conduct a controlled load test by running the machine at a steady speed on a representative load profile, monitoring engine RPM, transmission output, and hydrostatic pressure if applicable. Evaluate blade engagement stability under full and partial throttle, listening for unusual noises, vibration, or unusual blade tip resonance. Measure ground speed accuracy against the advertised specification, using a calibrated tachometer and timing method to verify the control system’s response time and stability under typical mowing conditions. After the bench tests, compare measured results with the service manual’s baseline values and adjust the fuel mixture, air filter condition, and cooling airflow as needed to maintain the proper operating envelope for temperature and emissions compliance.

Advanced calibration steps include verifying the governor set point, idle and maximum RPM limits, and fuel metering adjustments if the engine exhibits performance drift after servicing. Use the appropriate diagnostic tools to review sensor data, including throttle position, air intake, temperature sensors, and safety interlock states, ensuring all readings align with the OEM specifications. Re-check belt tension and pulley alignment for drive and cutting systems to sustain consistent belt life and predictable cutting performance. Perform a final functional sweep across all operating modes, including reverse mowing safety, to confirm that system behavior remains consistent under different conditions and temperatures. Keep detailed records of all calibration values and test outcomes to support future maintenance and troubleshooting.

Maintenance Records and Documentation

Keeping comprehensive maintenance records for the GRAVELY ZT HD STEALTH 60 is essential for ensuring reliable performance and preserving the machine’s value over time. A well-maintained log helps you track service intervals, identify recurring issues, and plan preventative maintenance before failures occur. Establish a consistent routine for documenting all inspections, adjustments, replacements, and consumable changes. This allows technicians and owners to review the machine’s history at a glance and facilitates smoother handovers if ownership changes.

Maintaining detailed parts and service history enables precise diagnosing of symptoms and faster turnaround during repairs. Include dates, operator notes, hours of operation, and the specific maintenance tasks performed. Record any deviations from standard procedures, such as unusual wear patterns or component compatibility notes, to build a knowledge base for future reference. An organized service history also supports warranty compliance and can aid in identifying trend data that might indicate underlying design or component issues needing factory notification or service bulletins.

Keep a physical logbook and a digital backup to ensure information is never lost. For the digital record, store a copy in a cloud-safe location or a dedicated maintenance software folder, with clear file naming such as “ZT_HD_Stealth60_ServiceLog.xlsx” and version dates. Regularly back up scanned receipts, work orders, and parts invoices, attaching them to the corresponding service entries. The goal is to have a complete, tamper-evident trail of maintenance activities that is easy to review during inspections, resale assessments, or diagnostic sessions.

Parts and service history should be organized by system and component, such as drive belt, cutting deck, hydraulic system, electrical wiring, and safety interlocks. For each item, list part numbers, suppliers, purchase dates, and installation details, including torque specs and alignment checks where applicable. Document recurring parts that require periodic replacement, such as filters, seals, and lubrication points, with recommended replacement intervals and observed wear levels. This structured approach helps maintenance personnel quickly verify that all maintenance tasks have been completed and that no critical items have been skipped.