John Deere. MODEL: 8430 & 8630 Volume 1 of 2 JD-S-TM1143

Transcription

1 John Deere MODEL: 8430 & 8630 Volume 1 of 2 THIS IS A MANUAL PRODUCED BY JENSALES INC. WITHOUT THE AUTHORIZATION OF JOHN DEERE OR IT'S SUCCESSORS. JOHN DEERE AND IT'S SUCCESSORS ARE NOT RESPONSIBLE FOR THE QUALITY OR ACCURACY OF THIS MANUAL. TRADE MARKS AND TRADE NAMES CONTAINED AND USED HEREIN ARE THOSE OF OTHERS, AND ARE USED HERE IN A DESCRIPTIVE SENSE TO REFER TO THE PRODUCTS OF OTHERS. JD-S-TM1143

2 8430 and 8630 Tractors TECHNICAL MANUAL 8430 and 8630 Tractors TM1143 (01 NOV86) English John Deere Tractors Works TM1143 (01 NOVa6) LITHO IN U.S.A. ENGLISH

3 SECTION 10-GENERAL Group 5 - General Tractor Specifications Group 10 - Predelivery, Delivery and After-Sale Services Group 15 - Tune-Up Group 20 - Lubrication Group 25 - Separation Group 30 - Specifications and Special Tools SECTION ENGINE Group 5 - General Information, Diagnosis and Tests Group 10 - Cylinder Head, Valves and Camshaft Group 15 - Cylinder Block, Liners, Pistons and Rods Group 20 - Crankshaft, Main Bearings and Flywheel Group 25 - Lubrication System Group 30 - Cooling System Group 35 - Specifications and Special Tools SECTION ENGINE Group 5 - General Information, Diagnosis and Tests Group 10 - Cylinder Head, Valves and Camshaft Group 15 - Cylinder Block, Liners, Pistons and Rods Group 20 - Crankshaft, Main Bearings and Flywheel Group 25 - Lubrication System Group 30 - Cooling System Group 35 - Specifications and Special Tools SECTION 30-FUEL SYSTEM Group 5 - Diagnosing Malfunctions Group 10 - Air Intake System Group 15 - Diesel Fuel System Group 20 - Speed Control Linkage Group 25 - Specifications and Special Tools SECTION 40-ELECTRICAL SYSTEM Group 5 - Information and Diagrams Group 10 - Electrical Diagnosis Group 15 - Delcotron Charging Circuit Group 20 - John Deere Charging Circuit Group 25 - Delco-Remy Starting Circuit Group 30 - John Deere Starting Circuit CONTENTS 8430 AND 8630 TRACTORS TECHNICAL MANUAL Group 35 - Lighting Circuits Group 40 - Instrument and Accessory Circuits Group 45 - Remote Electrical Circuits Group 50 - Specifications and Special Tools SECTION 50-POWER TRAIN Group 5 - Perma-Clutch@> Group 10 - Quad-Range Planetary Group 15 - Independent PTO Group 20 - Torque Divider Group 25 - Quad-Range Transmission Group 30 - Differentials and Drive Shafts Group 35 - Final Drives Group 40 - Specifications and Special Tools SECTION 60-STEERING AND BRAKES Group 5 - General Information SECTION 70-HYDRAULIC SYSTEM Group Group 5 - General Information 6 - Hydraulic System Testing and Diagnosis Group 10 - Miscellaneous Hydraulic Components Group 15 - Hydraulic Pumps Group 20 - Power Steering Group 25 - Power Brakes Group 30 - Rockshaft and Implement Hitches Group 35 - Selective Control Valves, Breakaway Couplers and Remote Cylinders Group 40 - Specifications and Special Tools SECTION 80-S0UND-GARD BODY Group 5 - Separation Group 10 - Air Conditioning System Group 15 - Heating System Group 20 - Seat Group 25 - Miscellaneous Components Group 30 - Specifications and Special Tools SECTION go-miscellaneous Group 5 - Wheels Group 10 - Specifications All information, illustrations and specifications contained in this technical manual are based on the latest information available at the time of publication. The right is reserved to make changes at any time without notice. A-OO

4 General 10 General Tractor Specifications 5-1 Section 10 GENERAL GROUP 5 - GENERAL TRACTOR SPECiFiCATIONS GROUP 10 - PREDELIVERY, DELIVERY, AND AFTER-SALE SERVICES Predelivery Services... " 10-1 Delivery Services After-Sale Services... " 10-4 GROUP 15 - TUNE-UP Preliminary Engine Testing Engine Tune-Up... " 15-1 Engine Final Testing... " 15-3 Tractor Tune-Up GROUP 20 - LUBRICATION Lubrication Chart Engine Lubricating Oils... " 20-2 Transmission-Hydraulic Oil... " 20-2 Greases... " 20-2 Storing Lubricants GROUP 25 - SEPARATION General Information Drive Assembly With Front Drive Support Without Front Drive Support Engine General Information Method "A" Separation Method "B" Separation Clutch Housing Hinge General Information Between Hinges Front Hinge Rear Hinge Torque Divider Transmission GROUP 30 - SPECIFICATIONS AND SPECIAL TOOLS Specifications Special Tools Group 5 GENERAL TRACTOR SPECIFICATIONS Horsepower:* Maximum observed at PTO : (130 kw) (168 kw) Engine: Type... 6-cylinder, in-line, valve-in-head, diesel, turbocharged, and intercooled Engine Speeds: Slow idle rpm Working range to 2100 rpm Maximum transport speed rpm Bore and stroke x 4.75 in. (11.6 x 12.1 em) x 5 in. (13.0 x 12.7 em) Displacement cu. in. (7636 cm 3 ) , cu. in. ( cm 3 ) Compression ratio to '.15.4 t01 Firing order Valve clearance see see Injection pump timing TDC Lubrication System... Force-feed pressurized with full-flow oil filter and by-pass Fuel System: Type... Direct injection Injection pump type Multiple plunger, in-line Air cleaner... Dry type with safety element Cooling System: Type... Pressurized with centrifugal pump Temperature controlled by heavy-duty thermostats thermostats thermostats

5 General Separation Group 25 SEPARATION R 25270N A-Front Drive B-Engine C-Clutch Housing D-Hinge E-Torque Divider F-Transmission Fig. 1-Basic Separation Components GENERAL INFORMATION G-Final Drive H-Sound Gard Body Separation of the tractor may be subdivided into the following components (Fig. 1): Front drive (A), engine (B), front end, clutch housing (C}, front hinge, hinge pin, rear hinge, torque divider (E), transmission (F), final drive (G) and Sound-Gard body (H). Basic separation of these components will be explained within this group, except for the Sound-Gard body covered in Section 80, and final drive covered in Section 50. A CAUTION: Always use the hinge lock.. bars, provided with the tractor, whenever front or rear of tractor is raised. See operator's manual for installation of lock bars. It is important to determine beforehand, which component has to be removed and the best method to use in removing the component, in order to perform the required service in the shortest possible time. For example, it is possible to gain access to the engine clutch two different ways: (1) Removing engine and tractor front end from clutch housing, (2) Removing tractor front end, then removing engine from clutch housing. The method selected will be determined by the total service requirements for any particular job, and on personal choice. Once a basic component has been removed from the tractor, refer to the appropriate section of this manual for detailed service information. Litho in U. S.A.

6 8430 ENGINE Basic Engine A 20 General Information and Diagnosis 5-1 Section ENGINE GROUP 5 - GENERAL INFORMATION AND DIAGNOSIS General Information """"""""""",,5-2 Diagnosing Engine Malfunctions"","""" 5-2 GROUP 10 - CYLINDER HEAD, VALVES, AND CAMSHAFT General Information"",,"""""""" 10-1 Diagnosing Malfunctions"","""""'" 10-1 Preliminary Valve Checks"",",,,,,,,, " 10-2 Cylinder Head and Valves Removal and Repair,,,,,,,,,,,,,,,,, " 10-2 Assembly "",',',""","',',',',", Installation,,,,,,,,,,,,,,,,,,,,,,,,,,, " 10-4 Valve Clearance Adjustment",,,,,,,, " 10-5 Camshaft Removal ",',",',',"',""""',"', Repair,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, " 10-5 Installation,,,,,,,,,,,,,,,,,,,,,,,,,,, " 10-6 GROUP 15 - CYLINDER BLOCK, LINERS, PISTONS AND RODS General Information..., Diagnosing Malfunctions,,,,,,,,,,,,,,,, " 15-1 Removal """""""""""""",'" 15-2 Repair Pistons,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, " 15-2 Liners,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, " 15-4 Piston Pins"",""""""""""'" 15-4 Rods"""""""""""""""", 15-5 Block,,, ",,,,",, " ", '" " ", ", " " 15-6 Assembly and Installation"",,""',.,'" 15-6 GROUP 20 - CRANKSHAFT, MAIN BEARINGS, AND FLYWHEEL General Information,,,,,,,,,,,,,,,,,,,, " 20-1 Diagnosing Malfunctions,,,,,,,,,,,,,,,, " 20-1 Removal """""","","""""",' 20-2 Checking End Play""""""""""", 20-2 Inspection and Repair Flywheel,"',""""',"""""""'" 20-3 Rear Crankshaft Oil Seal, Housing, and Wear Sleeve,,,,,,,,,,, " 20-4 Main Bearings and Journals ",,,,,,,,,, " 20-4 Damper Pulley"",""""""""""" 20-5 Front Oil Seal and Wear Sleeve,,,,,,,, " 20-6 Installation,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, " 20-6 GROUP 25 - LUBRICATION SYSTEM General Information,,,,,,,,,,,,,,,,,,,, " 25-1 Diagnosing Malfunctions,,,,,,,,,,,,,,,, " 25-2 Checking Oil Pressure"""""""""" 25-2 Oil Filter and Housing Repair"",,""'" 25-2 Oil Cooler,,,,,,,,,,,,,,,,,,,,,,,,,,,,, " 25-3 Oil Cooler Bypass Valve Repair"",,"'" 25-3 Oil Pump Repair"",,""""""""'" 25-3 Installation,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,25-4 GROUP 30 - COOLING SYSTEM General Information"",,"""""""" 30-1 Diagnosing Malfunctions,,,,,,,,,,,,,,,, " 30-2 Radiator and Fan"",,""""""""" 30-2 Water Pump,,,,,,,,,,,,,,,,.,,,,,,,,,, " 30-2 Water Manifold and Thermostats,,,,,,,, " 30-4 GROUP 35 - SPECIFICATIONS AND SPECIAL TOOLS Cylinder Head, Valves, and Camshaft"", 35-1 Cylinder Block, Liners, Pistons and Rods " 35-1 Crankshaft, Main Bearings and Flywheel", 35-2 Lubrication System,,,,,,,,,,,,,,,,,,,,, " 35-2 Cooling System,,,,,,,,,,,,,,,,,,,,,,,, " 35-3 Engine Break-In ".,',""""',',""',' 35-3 Special Tools,,,,,,,,,,,,,,,,,,,,,,,,,, " 35-4 Litho in U,S.A.

7 8630 ENGINE Basic Engine A 25 General Information and Diagnosis 5-1 Section ENGINE GROUP 5 - GENERAL INFORMATION AND DIAGNOSIS General Information Diagnosing Engine Malfunctions GROUP 10 - CYLINDER HEAD, VALVES, AND CAMSHAFT General Information Diagnosing Malfunctions Preliminary Valve Train Inspection Cylinder Head and Valves Removal and Repair Assembly and Installation Valve Clearance Adjustment Camshaft Removal Repair Installation GROUP 15 - CYLINDER BLOCK, LINERS, PISTONS AND RODS General Information Diagnosing Malfunctions Removal Repair Pistons Liners Piston Pins Rods Assembly and Installation GROUP 20 - CRANKSHAFT, MAIN BEARINGS, AND FLYWHEEL General Information Diagnosing Malfunctions Checking End Play Removal Inspection and Repair Crankshaft and Flywheel Main Bearings and Journals Rear Crankshaft Oil Seal, Housing, and Wear Sleeve Damper assembly Front Oil Seal and Wear Sleeve Assembly...,... " Installation GROUP 25 - LUBRICATION SYSTEM General Information Diagnosing Malfunctions Oil Pressure Regulating Housing Repair Oil Pump Repair Assembly... " GROUP 30 - COOLING SYSTEM General Information Diagnosing Malfunctions Radiator and Fan Water Pump Water Manifold and Thermostats GROUP 35 - SPECIFICATIONS AND SPECIAL TOOLS Cylinder Head, Valves, and Camshaft Cylinder Block, Liners, Pistons and Rods Crankshaft, Main Bearings and Flywheel Lubrication System Cooling System Engine Break-In Special Tools

8 Piston Cooling Orifices 8630 ENGINE Basic Engine A 25 Cylinder Block, Liners, Pistons, and Rods 15-7 Install O-rings in grooves in bore and packing on cylinder liner. Apply AR54749 Lubricating Soap to 0- rings and packing. Work liners in place by hand and seat with wood block and hammer (Fig. 13). NOTE: Cylinder liner will protrude above the cylinder block more than normal due to uncompressed packing. Fig. 12-Piston Cooling Orifice Check each piston cooling orifice (Fig. 12) for plugged or damaged condition. An orifice failure could cause damage to pistons, piston pins, rod pin bushings, and liners. Replace orifices as necessary. Tighten to 85 to 110 in-ibs (9.60 to Nm). ASSEMBLY AND INSTALLATION Liners Piston and Rod Assembly Be sure identification marks on piston and rod are in the same position as they were at time of disassembly. Use a JOE-94 Ring Expander to install rings in their respective grooves. NOTE: New rings are furnished with the correct end gap; therefore, filting to the liner is not necessary. Install expander in oil ring groove. Install the oil ring on the piston with the expander to the top of the piston. Position oil ring gap opposite expander gap. Coat pistons, liners, and JOE-97 ring compressor (Fig. 12) with engine oil. Fig. 14-lnsta/ling Piston Fig. 13-lnstalling Cylinder Liner Be sure liner bore in cylinder block is clean. First, install liner without O-rings and secure with cap screws and washers. Check liner height in several places. If installation is in new cylinder block, the height of the liner should be inches ( mm). If installation is in used cylinder block, the height of the liner should be inches ( mm). NOTE: Install liner with the "L-L" or "H-H" mark toward the front of the engine. Stagger ring gaps on piston and carefully slide ring compressor over piston. Carefully place ring compressor, with piston and rod, over liner. With piston and rings centered, push piston into liner. NOTE: Be sure the words "front" on head of piston and rod face front of engine. Apply engine oil to bearing inserts and crankshaft rod of journals. Small tangs on each half of the inserts must fit in recesses in rod and cap.

9 Fuel System 30 Diagnosing Malfunctions 5-1 GROUP 5 - DIAGNOSING MALFUNCTIONS GROUP 10 - AIR INTAKE SYSTEM Pre-Cleaner..., 10-1 Aspirator Air Cleaner Restriction Indicator Switch AiResearch Turbochargers Schwitzer Turbochargers Intercoolers Ether Starting Aid GROUP 15 - DIESEL FUEL SYSTEM General Information.... Fuel Tanks.... Fuel Tank Venting.... Fuel Gauge Sender.... Fuel Supply Pump.... Fuel Check Valve.... Fuel Filters Section 30 FUEL SYSTEM GROUP 15 - DIESEL FUEL SYSTEM (Cont'd) Bleeding Fuel System Fuel Injection Pump Aneroid Hydraulic Aneroid Activator Overflow Valve...,... '" Fuel Injection Nozzles GROUP 20 -' CONTROL LINKAGE Speed Control Linkage Foot Throttle Linkage Starting Fuel Control Linkage Diesel Fuel Shut-Off Control GROUP 25 - SPECIFICATIONS AND SPECIAL TOOLS Specifications Special Tools Group 5 DIAGNOSING MALFUNCTIONS The following is a guide for diagnosing fuel system malfunctions. For specific diagnosis of fuel system components. refer to the groups which cover complete servicing. Fuel Not Reaching Injection Nozzles Filters clogged. Fuel line clogged or restricted. Fuel too heavy at low temperatures. Air in system. Low supply pump pressure. Engine Starts Hard or Won't Start Air leak on suction side of system. Fuel too heavy at low temperatures. Injection nozzles faulty or sticking. Incorrect timing Governor is faulty or not operating. Water in fuel. Filters clogged. Injection pump return fuel line or' fittings restricted. Low cetane fuel. Starting fuel control linkage or aneroid activator not working properly. Engine Starts and Stops Air in system. Filters clogged. Fuel lines clogged or restricted. Water in fuel. Injection pump return fuel line or fittings restricted. Erratic Engine Operation Filters clogged. Air leak on suction side of system. Fuel too heavy at low temperatures. Injection nozzles faulty or sticking. Fuel lines clogged or restricted. Incorrect timing. Governor faulty or not operating. Water in fuel. Injection pump return fuel line or fittings restricted. Low cetane fuel. Injection nozzle return lines clogged.

10 Electrical System 40 Information and Diagrams 5-1 Section 40 ELECTRICAL SYSTEM GROUP 5 - INFORMATION AND DIAGRAMS Precautions Batteries Circuit Breakers Accessory Relay Key Switch Wiring Changes During Production Wiring Diagrams Bulkhead Connector Harness Replacement GROUp ELECTRICAL SYSTEM DIAGNOSIS Electrical Diagnostic Kit Electrical System Diagnosis GROUP 15 - DELCOTRON CHARGING CIRCUIT General Information How the System Works Precautions Removal Disassembly Repair Assembly Installation GROUP 20 - JOHN DEERE CHARGING CIRCUIT General Information How the System Works Precautions Removal Disassembly Repair Installation GROUP 25 - DELCO-REMY STARTING CIRCUIT General Information How the System Works Starter Removal Tests Before Disassembly Disassembly and Repair Installation GROUP 30 - JOHN DEERE STARTING CIRCUIT General Information How the System Works Starter Removal Tests Before Disassembly Disassembly and Repair Assembly Installation GROUP 35 - LIGHTING CIRCUITS General Information Flood Lamps Head Lamps and Tail Lamps Turn Signals and Warning Lamps Light Switch Instrument, Indicator, and Console Lamps Dome Lamp Bulb Replacement GROUP 40 - INSTRUMENT AND ACCESSORY CIRCUITS Instrument Cluster Accessories GROUP 45 - REMOTE ELECTRICAL CIRCUITS Electrical Remote Control Outlet Socket GROUP 50 - SPECIFICATIONS General Information Delcotron Charging Circuit John Deere Charging Circuit Starting Circuit Lighting Circuits Instrument Circuits Accessory Circuits Special Tools

11 Power Train 50 Perma-Clutch 5-1 GROUP 5 - PERMA-CLUTCH General Information Perm a-clutch Operating and Lubricating Circuit Diagnosing Malfunctions Testing..., 5-11 Operating Piston Housing and Clutch Valve Housing Removal..., Repair Assembly ' Installation Clutch Assembly Removal Repair Assembly Installation and Adjustment Rod Adjustment..., 5-25 Clutch Oil Pump Drive Gear GROUP 10 - QUAD-RANGE PLANETARY General Information Diagnosing Malfunctions..., 10-5 Testing..., 10-5 Repair Removal Disassembly and Inspection Assembly Installation... " Adjustment GROUP 15 - INDEPENDENT PTO General Information..., 15-2 Diagnosing Malfunctions..., 15-4 Testing Removal Repair Assembly and Installation GROUP 20 - TORQUE DIVIDER General Information Diagnosing Malfunctions Repair Inspection and Assembly Section 50 POWER TRAIN GROUP 25 - QUAD-RANGE TRANSMISSION General Information Diagnosing Malfunctions Removal Repair Assembly Range And Speed Selector Lever Assembly Rod and Bell Crank Design Removal and Repair Assembly and Adjustment One-Piece Cable Design Removal Repair Assembly and Adjustment Transmission Oil Pump GROUP 30 - DIFFERENTIALS AND DRIVE SHAFTS Differentials Rear Differential Removal Repair Assembly and Installation Differential Lock Front Differential Removal Repair Assembly and Installation Draining, Filling and Checking Front Differential Oil Drive Shafts General Information Repair Installation Timing Drive Shafts GROUP 35 - FINAL DRIVES General Information Removal Disassembly and Repair Assembly and Adjustment Rolling Drag Torque Installation GROUP 40 - SPECIFICATIONS AND SPECIAL TOOLS Specifications Special Tools Litho in U. S.A.

12 50 Power Train 5-12 Perma-Clutch Lubrication Flow Test Check clutch oil pump output as instructed in Section 70, Group 15. This measures the oil which is delivered to the oil cooler and then returned for lubrication. Refer to Fig. 2 for lubrication flow schematic. Oil Pressure Switch Test Removal Tractors and 8630 OPERATING PISTON HOUSING AND CLUTCH VALVE HOUSING Disconnect and remove the upper telescoping U joint from the clutch output yoke while the tractor is in a straight position. After the U-joint is removed, then put the tractor in a sharp right turn. Separate engine from clutch housing. Refer to Section 10, Group 25, for procedures. A. CAUTION: Use necessary safety precau.. tions when performing separation. Use support under sections when necessary. A-D-01019AA Hand Pump psi (0-25 bar) Pressure Gauge C-Ohmmeter D-Oil Pressure Switch Fig. 13.Testing Pressure Switch Remove the oil p~essure switch (Fig. 8). Connect the switch to a hydraulic hand pump. Connect a 12-volt test lamp and battery across the switch leads. The switch should open as the pressure is raised to 145 to 155 psi (999 to 1068 kpa) and close when the pressure is reduced to 115 to 125 psi (792 to 861 kpa). A-Oil Lines B-PTO Rod C-Clutch Rod D-Operatlng Arms Fig. 14-Pressure Regulating Valve Housing (Late Model Shown) Remove oil lines (A, Fig. 14) and operating rods (B) from pressure regulating valve housing. On some tractors the operating rods are secured to the operating arms by spring pins. Remove these spring pins to disconnect rods from arms. On other tractors the rods are secured to the operating arms by retaining rings (Fig. 15). The rods cannot be disconnected until the operating arms are removed from the operating arm shafts. Remove spring pin securing arms to shaft and remove arms. Later tractors (Fig. 14) are headed pins and retainer pins to connect the operating rods to their arms.

13 Hydraulic System 70 General Information 5-1 Section 70 HYDRAULIC SYSTEM GROUP 5 - GENERAL INFORMATION General Information GROUP 6 - GENERAL HYDRAULIC SYSTEM DIAGNOSIS AND TESTS General Information Safety Precautions Step-By-Step Diagnosis Special Tools How To Use Step Charts Heating Hydraulic Oil Preliminary Checks Tractor Charts GROUP 10 - MISCELLANEOUS HYDRAULIC COMPONENTS Reservoir and Filter Hydraulic Oil Relief and Check Valves Pressure Control Valve Oil Cooler GROUP 15 - HYDRAULIC PUMPS Clutch Oil and Oil Transfer Pump Operation Diagnosis and Test Repair Main Pump Operation Diagnosis and Test Removal and Repair Inspection Adjustment GROUP 20 - POWER STEERING General Information Operation Diagnosing Malfunctions Repair Metering Pump Steering Valve Steering Cylinders GROUP 25 - POWER BRAKES General Information and Operation Diagnosing Malfunctions Brake Cylinders, Plates and Disks Brake Valve Adjustment..., 25-6 Bleeding Brakes Brake Accumulator Pre-charging Accumulator Accumulator Test GROUP 30 - ROCKS HAFT AND IMPLEMENT HITCHES General Information and Operation..., 30-1 Diagnosing Malfunctions Rockshaft Rockshaft Valve Housing Console Levers Load Sensing Cylinder Point Hitch... " Final Rockshaft Installation GROUP 35 - SELECTIVE CONTROL VALVES, BREAKAWAY COUPLER AND REMOTE CYLINDER General Information and Operation Diagnosing and Testing Removal and Disassembly..., 35-6 Inspection, Repair and Assembly Adjustment Breakaway Coupler SCV Installation Remote Cylinder GROUP 40 - SPECIFICATIONS AND SPECIAL TOOLS General Information Hydraulic System Diagnosis and Tests Reservoir, Valves and Oil Cooler..., 40-1 Hydraulic Pumps Power Steering Power Brakes..., 40-4 Rockshaft and Implement Hitches..., 40-4 Selective Control Valves..., 40-5 Special Tools..., 40-7

14 Miscellaneous 90 Wheels 5-1 Section 90 MISCELLAN EOUS GROUP 5 - WHEELS General Information Removal Repair..., Installation GROUP 10 - SPECiFiCATIONS Group 5 WHEELS GENERAL INFORMATION Both the 8430 and 8630 tractor main drive wheels are of the cast disk type mounted on Rack and Pinion axles. When double wheels are used (either front or rear), the outer wheel may be a cast or steel disk type. Removal 1. (Not Illustrated). Clean the axle with a steel brush. 2. (Not Illustrated). Position the tractor so that the rack on the axle is up. 3. (Not Illustrated). Jack up the tractor. Fig. 1-Removing Snap Ring To remove or change position of a rear wheel, follow the instructions given in the Operator's Manual. Use JOG-18 Snap Ring Tool to remove snap ring from axle. (See Fig. 1.) 'R NL.'. Fig. 2-Removing Wheel 4. Use JOG-18 Snap Ring Tool to remove axle snap ring (Fig. 1). 5. Loosen the three special bolts approximately 3/8 in. (10 mm).