David Brown front axle


TIE RODS AND TOE-IN 
Front wheel toe-in should be 0-1.5 mm measured from wheel rim to wheel rim at front and rear of wheels. Toe-in is adjusted by lengthening or shortening the threaded tie rod ends equally. Tie rod ends that are excessively worn must be renewed as complete units.

Remove & Reinstall AXLE 
David Brown front axle final drives and differential may be serviced without removing entire axle and differential housing assembly. However, if housing or trunnion pin are to be serviced, it will be necessary to remove axle housing assembly.


Fig. 1 - David Brown front drive axle used on some models showing component parts and their relative positions.

To remove assembly, first disconnect all steering lines and cap openings. Loosen locknuts (6—Fig. 1) on trunnion shaft cotter pins (31) until they are even with threaded ends. Using care to avoid damaging threads, drive cotter pins (31) through trunnion shaft. Remove locknuts and washers from cotter pins and remove pins (raise right end of axle for more clearance). Support axle and remove core plug (7) from trunnion shaft bore with punch and hammer. Use slide hammer to pull trunnion shaft (33). Raise front of tractor enough to clear axle and remove axle. Remove thrust washers (36) and "O" rings (35 and 37). To reinstall, reverse removal procedure. Bleed steering system.

RENEW TRUNNION SHAFT BUSHINGS 
Remove axle assembly. Remove the four trunnion shaft bushings (34—Fig. 1) using a suitable puller. Install bushings making certain grease hole in each bore is between the two bushings. Refer to Fig. 2 for correct bushing placement.


Fig. 2 - Diagram showing correct dimensions tor the placement of trunnion shah bushings for models equipped with David Brown front drive axles.

If trunnion shaft bracket (32—Fig. 1) is to be renewed, remove bracket from axle housing and remove dowel pins. Loosely bolt new bracket to housing and drive dowel pins in. Tighten bolts to 203-244 Nm (150-180 ft.-lbs.) torque.
Lubricate "O" rings and place in thrust washer grooves. When reinstalling thrust washers (36), "O" ring is toward front at front position and toward rear at rear position.

FINAL  DRIVE  AND  STUB AXLE 
Left and right final drive removal procedure is similar. To remove, raise and support side to be serviced and remove tire and wheel. Rotate hub so drain plug is at bottom and drain fluid. Remove end plate (12—Fig. 3) and use pry bars to pull sun gear (15) and shaft (1—Fig. 4) out approximately 5 mm.


Fig. 3 - David Brown front drive axle final drive showing relative position of their component parts.

Axle shaft seals can be damaged it axle shaft Is pulled out too far.


Fig. 4 - David Brown front drive stub axle showing component parts and their relative positions.

Hold axle shaft out and push sun gear in until split rings (14—Fig. 3) can be removed. Remove sun gear (15) and thrust washer (16). Do no push axle shaft Into axle housing as oil seal damage could occur.
Bend tab washer (2—Fig. 3) away from locknut (1) and remove nut with special spanner wrench. Remove tab washer (2), planetary ring gear (3) and bearing cup assembly (4).
Note number and thickness of shims (5) and remove. Remove spacer (6) and hub (7). Seal (10) in hub will be tight on axle and should stay on stub axle as hub is removed. Remove bearing (9) and seal (10).
Oil seal wear sleeve (11) should be renewed if damaged or worn. Use a chisel to cut through wear sleeve being careful not to damage surface of stub axle. Install new sleeve on axle making sure side with inside chamfered edge goes onto axle first. Remove steering lever (4—Fig. 4) and bolts retaining upper and lower bearing pins (6 and 10). Remove bearing pins using jack screws in threaded hole of bearing pins. Retain shims (7) for use in reassembly. Hold axle shaft in place while removing stub axle assembly to prevent damage to oil seals. Remove axle shaft from housing.

Remove upper and lower sealing discs (28 and 17—Fig. 1), "O" rings (27 and 16) and bearings (26 and 15) from axle housing (13). Use a suitable puller to remove upper and lower bearing cups from axle housing. Remove upper and lower shields (25 and 14).
Remove seal (2—Fig. 4) from inside stub axle (8). Using a suitable bushing driver, drive bushing (3) out oil seal end of stub axle. Install new bushing from seal end until it seats in stub axle. Install new oil seal with lip of seal entering bore first.
To reassemble, reverse disassembly procedure using care not to let axle shafts damage oil seals and noting preload must be set on bearing pin bearings and stub axle bearings.
To set bearing pin preload, reassemble unit minus shims (7—Fig. 4). Tighten lower bearing pin mounting bolts to 68 N-m (50 ft.-lbs.) torque and upper bearing pin mounting bolts to 20 N-m (15 ft.-lbs.) torque. Push stub axle up tight against bottom of axle housing and use a feeler gage to measure gap between upper bearing pin flange and stub axle. Remove upper bearing pin, then assemble shims so total thickness is 0.381 mm (0.015 inch) less than feeler gage measurement. This will correctly preload bearings to 0.10-0.15 mm (0.004-0.006 inch) when full load is on axle. Tighten upper bearing pin bolts to 68 N-m (50 ft.-lbs.) torque. Refer to paragraph 11 to set stub axle bearing preload.

WHEEL HUB BEARING PRELOAD
To set stub axle bearing preload, install shims (5—Fig. 3) having a total thickness of 2 mm (0.080 inch) next to spacer (6). Install planetary ring gear (3) and nut (1) minus tab washer (2). Using special spanner wrench, tighten nut (1) to 203 N-m (150 ft.-lbs.) torque. Mount dial indicator so point of probe contacts outside face of hub. Measure and record amount of end play. Correct amount of bearing preload is 0.08-0.13 mm (0.003-0.005 inch). Subtract shims equal to measured end play plus 0.10 mm (0.004 inch) from previously installed shim pack to obtain correct bearing preload.
Reassemble unit installing tab washer (2—Fig. 3) and making sure flat side of nut (1) faces inward. Tighten nut to 203 N-m (150 ft.-lbs.) torque, then secure with tab washer. Fill each final drive with 0,9 L (1 quart) of gear lubricant or equivalent.

PLANETARY GEAR ASSEMBLIES
Drain fluid, then remove end plate (12—Fig. 3), Remove lock plates (22) and bolts retaining planetary gear carrier (20) to end plate (12). Mark gear carrier, pins, gears and bearings prior to disassembly so they can be reassembled in their original positions. Remove carrier, gears and bearings.
Reassemble by reversing disassembly procedure making certain gears, bearings and pins are reinstalled  in their original positions. Install lock plates so they cover dowel pin holes and tighten bolt's to 40 N-m (30 ft.-lbs.) torque. Reinstall end plate, tighten bolts to 100 N-m (75 ft.-lbs.) torque and fill hub to proper level with gear lubricant or equivalent.

AXLE HOUSINGS
Axle shaft seal (23—Fig. 1) and bushings (24) can be renewed with axle housings in place. If removal of housing is necessary, raise and support front of tractor and remove tire and wheel from side to be serviced. Drain oil from differential housing. Capacity is approximately 8 L (8.5 quarts). Attach hoist to axle housing so weight is equally balanced. Disconnect steering linkage and remove bolts retaining axle housing to differential housing, then remove axle housing. Remove final drive from axle housing if necessary.
To reinstall axle housing, reverse the removal procedure. Tighten housing mounting bolts to 110-130 N-m (80-95 ft.-lbs.) torque. Fill differential housing to correct level with gear lubricant or equivalent.