John Deere MODEL: 120 Hydrostatic Tractor 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-SM2090
Service Manual 120 HYDROSTATIC TRACTOR CONTENTS SECTION 10 ~ GENERAL Group 5 - Tractor Identification Group 10 - Specifications Group i 5 - Tune-Up and Adjustment Group 20 - Fuel and Lubricants SECTION 20 - ENGINE Group. 5 - G~neral Information Group 10 - Cylinder Head, Valves and Breather Group 15 - Piston, Crankshaft, Main Bearings and Flywheel Group 20 - Camshaft, Tappets, and Governor Group 25 -. Engine Balancing System SECTION 30 - FUEL SYSTEM Group 10 - Carburetor Group 15 - Air Cleaner Group 20 - Fuel Strainer and Gas Tank SECTION 50 - POWER TRAIN Group 10 - Engine Disconnect, Drive Shaft, Couplings and Brakes Group 15 - Hydrostatic Transmission Group 20 - Control Cam and Linkage Group 25 - Differential and Axle SECTION 60 - HYDRAULIC LIFT SYSTEM Group 10 - Hydraulic Circuits Group 15 - Hydraulic Control Valve Group 20 - Hydraulic Cylinders SECTION 70 - MISCELLANEOUS Group 10 - Steering Assembly Group 15 - Front Wheels and Axle Group 20 - Fender-Deck and Seat Assembly SECTION 40 - ELECTRICAL SYSTEM Group 10 - Cranking System Group 15 - Ignition System Group 20 - Charging System Group 25 - PTO Clutch, Lights and Accessories
Section 10 GENERAL Group 5 TRACTOR IDENTIFICATION TABLE OF CONTENTS Page Page GROUP 5 - TRACTOR IDENTIFICATION Serial Numbers... 5-2 Identification Codes... 5-2 Tractor Codes........................ 5-2 Tire Codes... 5-2 Hydraulic System Codes... 5-2 GROUP 10 - SPECIFICATIONS Engine Specifications... 10-1 Capacities............................ 10-1 Tractor Specifications................... 10-2 Bolt Torque Chart... 10-3 Set Screw Seating Torque Chart... 10-3 GROUP 15 - TUNE-UP AND ADJUSTMENT Preliminary Engine Testing... 15-1 Minor Tune-Up Guide... 15-1 Major Tune-Up Guide... 15-2 Common Adjustments... 15-2 GROUP 20 - FUEL AND LUBRICANTS Fuel... 20-1 Lubricants... 20-1 Capacities............................ 20-1 Type of Lubricant... 20-2 Service Intervals... 20-2 Changing Crankcase Oil... 20-3 Changing Hydrostatic Drive Oil and Filter... 20-3 Grease Fitting Locations... 20-4
10 General 10-2 Specifications Tractor, Hydrostatic - 120 SM-2090- (Feb-70) TRACTOR SPECIFICATIONS Item 120 Tractor with GT-3 Tires 120 Tractor with GT-4 Tires 120 Tractor with GT-5 Tires WHEEL TREAD Front... 30-1/4 in. Rear... 29 or 35 in. TI RE SIZES (Also see Group 5)* Front............................ 16x6.50-8 2 ply Rear... 23x8.50-12 2 ply TIRE INFLATION* Front... 6 to 16 psi Rear... 8 to 10 psi DIMENSIONS Wheel Base... 46 in. Over-all Length... 67-1/2 in. Over-all Height... 43 in. Over-all Width: (min.)... 37 in. (max.).... 42-1/2 in. CURB WEIGHT... 7361bs. 30-1/4 in. 29 or 35 in. 4.80/4.00-84 ply 23x8.50-12 2 ply 12 to 40 psi 8t010psi 46 in. 67-1/2 in. 43 in. 37 in. 42-1/2 in. 7361bs. 30-1/4 in. 30-1/2 or 32-1/2 in. 16x6.50-8 2 ply 23x1 0.50-12 2 ply 6 to 16 psi 8 to 10 psi 46 in. 67-1/2 in. 43 in. 37 in. 42-1/2 in. 7361bs. FU EL SYSTEM - See Section 30 for detailed specifications. ELECTRICAL SYSTEM - See Section 40 for detailed specifications. TRANSMISSION - See Section 50 for detailed specifications. 01 FFERENTIAL - See Section 50 for detailed specifications. ENGINE DISCONNECT AND BRAKE - See Section 50 for detailed specifications. STEERING AND WHEEL BEARINGS - See Section 70 for detailed specifications. * The GT-6 and GT-7 tire combinations are available as options. They are as follows: GT-6 ------ G T-7 ------ GT-3 Front High-Flotation Tires and GT-4 Traction Rear Tires. G T-4 Front Tires and G T-5 High-Flotation Rear Tires.
Tractor, Hydrostatic - 120 SM-2090-(Feb-70) General 10 Tune-Up and Adjustment 15-1 Group 15 Tune-up and Adjustment IMPORTANT: Before attempting to tune-up the 120 Tractor engine, first determine if it is in a condition where by performance can be restored by tune-up. Do this by making the preliminary engine tests below. PRELIMINARY ENGINE TESTING Operation Specification Reference Cylinder compression 110-120 psi (1000 rpm) Section 20, Group 5 Crankcase vacuum 5-10 inches of water column Section 20, Group 5 Battery hydrometer test 1.260-1.280 sp. gr. 100% Section 40, Group 10 charged at 80 F. MINOR TUNE-UP GUIDE Operation Specification Reference Change oil Summer above 32 F.- Section 10, Group 20 SAE 30 (AM30730) Winter below 32 F.- SAE 5W-20 (AM30710) Clean and regap spark plug Clean electrodes Section 40, Group 15 Clean insulation Replace gasket Set gap at 0.025 in. Remove air cleaner and clean by Check air cleaner Section 30, Group 15 tapping lightly against flat condition surface Replace if necessary Adjust carburetor High speed mixture needle Section 30, Group 10 Idle mixture needle Adjust governor speed Speed (fast)- Section 20, Group 20 3800 rpm no load; Speed (idle)- 1200-1700 rpm Check and clean fuel tank and Regular gasoline only Section 30, Group 20 strainer. Litho in U. S.A.
10 15-2 General Tune-Up and Adjustment Tractor, Hydrostatic - 120 SM-2090-(Feb-70) MAJOR TUNE-UP GUIDE IMPORTANT: Major tune-up should include all items listed for "Minor Tune-Up" on page 15-1 in addition to the following: Operation Specification Reference Recondition carburetor Install carburetor kit Section 30, Group 10 I nspect and clean breather Replace parts as necessary. Section 20, Group 10 assembly Install new gaskets. Check crankcase vacuum after assembly Remove shrouding, clean engine... Section 20, Group 10 and cylinder head fins Test condenser See Manufacturer's Section 40, Group 15 Specifications Test coil See Manufacturer's Section 40, Group 15 Specifications Replace breaker points Point gap 0.020 in. Section 40, Group 15 Retime ignition "SP" or "S" mark on fly- Section 40, Group 15 wheel at 1200-1800 rpm COMMON ADJUSTMENTS NOTE: The following common adjustments are recommended after engine tune-up is completed. Adjustment Specification Reference Engine disconnect... Section 50, Group 10 Steering linkage... Section 70, Group 10 Brakes... Section 50, Group 10 Speed control... Section 50, Group 20 Litho in U. S.A.
Tractor, Hydrostatic-120 SM-2090-(Feb-70) General 10 Fuel and Lubricants 20-1 Group 20 FUEL AND LUBRICANTS FUEL Use only regular grade gasoline of a recognized brand. It should be fresh and from a supply blended for the area in which it is to be used. Summer blends held over for winter use will not vaporize properly at lower temperatures and may be the real reason for slow starts. Never use white gasoline. Do not mix oil with gasoline. Never use premium grade gasoline (ethyl) in small tractor engines. The compression ratio is not high enough to require the premium grade and it can cause a severe buildup of lead deposits in the engine. The deposits will rob power and may shorten the life of the engine. LUBRICANTS Carefully written and illustrated instructions have been included in the operator's manual furnished with your customer's machine. Remind your customer to follow the recommendations in those instructions. Oil used in the engine crankcase should have an American Petroleum Institute (API)/SAE classification of Service MS. Never fill engine crankcase above full (F) mark on dipstick. The charts below and on the next page indicate the type of lubricant, capacities and service intervals recommended for the 120 Tractor. CAPACITIES Component Fuel tank Crankcase Transmission Quantity 1-3/4 U.S. Gallons 3 U.S. Pints* 5 U.S. Quarts* * Initial capacity or after complete disassembly. See pages 20-3.
10 General 20-2 Fuel and Lubricants Tractor, Hydrostatic - 120 SM-2090- (Feb-70) TYPE OF LUBRICANT Crankcase - (API)/SAE Service MS Detergent type Summer - Above 32 F... SAE 30 - John Deere AM30730 Winter - Below 32 F... SAE 5W-20 - John Deere AM30710 Transmission... John Deere Type 303 Special-Purpose Oil or Automatic Transmission Fluid-Type "A" Tractor Grease Fittings and Front Wheel Bearings... SAE Multi-Purpose Type Grease SERVICE INTERVALS Crankcase (Oil change) Break-in... First 2 hours Regular........................................ Every 25 hours Dusty conditions................................. Every 8 hours Transmission... 500 hours or 2 years Transmission Oil Filter... 500 hours or 2 years Tractor Grease Fittings (See page 20-4 for locations)... Spring and fall season Front Wheel Bearings (repack)... 250 hours
Tractor, Hydrostatic - 120 SM-2090- (Feb-70) General 10 Fuel and Lubricants 20-3 CHANGING CRANKCASE Oil CHANGING HYDROSTATIC IVE Oil D FilTER Fig. 1-Removing Drain Plug Remove drain plug and allow oil to drain into container, Figure 1. NOTE: The best time to drain crankcase is when the oil is hot. Dirt and foreign material in the crankcase is in suspension and is easier to drain out. Fig. 3-Changing Transmission Oil Filter IMPORTANT: Be extremely careful to prevent dirt or foreign material from entering the hydraulic system when changing filter. Clean dust and dirt from the edges of the filter before removing. Unscrew and discard oil filter, Figure 3. If removal is difficult, a filter removal tool can be used. See your John Deere Dealer. Install a new John Deere oil filter. Moisten rubber gasket with transmission oil prior to installation. IMPORTANT: Tighten only finger tight. FILLER TUBE Remove cooling tube to drain oil from transmission. M B8!J1 Fig. 2-Dipstick and Filler Tube After the oil is drained, install drain plug and add 2-112 pints of the proper viscosity oil through filler tube, Figure 2. Check dipstick and add another halfpint if dipstick reading indicates necessity. Fig. 4-Transmission Filler Tube and Dipstick Add 3 quarts of oil. Check dipstick. Then add up to 2 additional quarts until level is to midpoint of "SAFE" range on dipstick, Figure 4. Use only John Deere Type 303 Special-Purpose Oil or Automatic Transmission Fluid Type "A." Make final check with engine running and transmission control lever in neutral.