Drive Axles, Bearings and Joints: Service and Repair
REMOVAL AND INSTALLATION OF REAR AXLE SHAFTS
Note:
- These instructions cover the removal and installation of rear axle shafts for all models. On vehicles with starting torque compensation there are small deviations which are described.
- If both rear axle shafts are to be exchanged, it will be of advantage to remove the complete rear axle center piece.
Removal
1 Drain oil from rear axle.
2 Unscrew caliper at respective end and hang up with a hook. Not required for rear axles with starting torque compensation.
On rear axle with starting torque compensation, if required, unscrew brake hose on holder and close brake line as well as brake hose against penetration of dirt.
3 Loosen hex bolt M12 of 1st version or hex bolt M8 of 2nd version with spacing sleeve and clamping disc for attaching rear axle shaft to rear axle shaft flange and remove.
4 Force rear axle shaft out of rear axle shaft flange by means of assembly tool.
Attention! When removing assembly tool, be sure to hold rear axle shaft in place. Do not permit rear axle shaft to drop, since this will damage the synchromesh joint and result in leaks. If on models 114 and 115 the rear axle shaft cannot be removed in spite of being completely telescoped, loosen upper shock absorber suspension and lower semitrailing arm against deflection stop.
On models 107, 116, 123 and 126 loosen rear axle center piece from rear axle carrier and lower until studs are out of rear axle carrier (concerns mainly vehicles with starting torque compensation). Swivel rear axle center piece to pertinent side until rear axle shaft can be removed.
5 Support rear axle housing with pitlift or vehicle jack and respective top.
6 On 1st version of rubber bearing, unscrew hex. socket necked-down bolt for rubber bearing on rear axle end cover. (Model 114 and 115) On 2nd version, unscrew hex. bolts from rubber bearing.
7 Clean rear axle housing. Unscrew hex. bolts for attaching cover to rear axle housing and remove cover.
8 Pull off locking ring (26) between inner synchromesh joint and side gear by means of pliers (1) or a hook and remove from housing.
9 Pull rear axle shaft out of side gear and remove together with spacing ring.
Installation
Attention! Rear axle shafts are provided with oil return threads (twist) on running surface of radial sealing ring, which are different for left and right. For identification, the face of the inside joint is provided with an electrically written "R" for the righthand side and an "L" for the lefthand side. The oil return feed thread or the identification is in place up to September 1979 on models 107.023/024/043/044, 116.028/029/03 and up to February 1981 on models 107.022/042 and 123.
10 Refinish oil return feed thread, if required, with emery cloth (grit 180) at an angle of approx. 20° and for a length of 20-30 mm.
Note: When installing a radial sealing ring with alternating feed thread, refinishing of oil return feed thread is not necessary. If a rear axle shaft is installed without oil return feed thread, make sure that a radial sealing ring with alternate feed thread is installed.
11 If a new rear axle shaft is installed, place the previously removed spacing ring (11) on inner synchromesh joint.
12 Introduce complete rear axle shaft into side gear and insert new locking ring into groove of inner synchromesh joint.
Attention! If the rear axle shaft cannot be introduced into differential housing up to contact surface, contract both joints first. Then apply light blows with a plastic hammer against outer spider to knock rear axle shaft against contact surface of differential housing. Do not apply hammer blows against stop sleeve.
Do not permit rear axle shaft to drop or to bend sharply, since this will damage housing for synchromesh joint and result in leaks.
13 Check end play between inner spider and differential housing. There should be no noticeable end play; the locking ring (26~ should just barely turn in groove. If required, use thicker or thinner spacing ring (27~.
Attention! Renew locking ring after one-time use.
14 Telescope rear axle shaft completely and insert into rear axle shaft flange (78) by means of assembly tool (05a-05c).
15 On version 1, tighten hex. screw M 12 to 95 Nm. On version 2, mount hex. screw M 8 with clamping disc and spacing sleeve and tighten to 30 Nm.
Attention! Renew clamping disc after one-ti me use. Provide clamping disc with oil in range of screw head. Pay attention to correct length of spacing sleeve and hex. screw.
Note: In the event of complaints about clicking noises, exchange hex. screw M 12 with a thick washer for a hex. screw M 8 with pertinent spacing sleeve and clamping disc. To reduce threads, screw a threaded bushing (79c) into rear axle shaft by means of self-made tool (details at the left). Tightening torque of threaded bushing 30 Nm.
Attention! When installing a new or a reconditioned rear axle shaft with one-piece protective sleeve on outer joint, check semi-trailing arm in operating range of protective sleeve for weld residue. Remove weld beads, since otherwise the protective sleeve may be chafed through. Also check installed rear axle shaft for wiping noises. If wiping noises are heard when rotating rear axle shaft, refinish wheel carrier in operating range of protective sleeve (arrows).
16 Mount rear axle end cover with sealing compound and tighten hex. screws to 45 Nm.
Model 107,114,115,116 and 123
17 Lift rear axle housing and screw rubber bearing to frame floor. Tighten hex. screws (version 1) to 25 Nm or self-locking hex. screws (version 2) to 30 Nm.
Attention! Use self-locking hex. screws only once.
Model 126
18 Lift rear axle center piece up to frame floor and attach rubber bearing to frame floor. Tightening torque of self-locking hex. screws of version 1 or hex. screws of version 2 30 Nm.
19 In the event of repairs, replace version 1 by version 2.
Attention! Always renew holder of version 2 after one-time use on principle.
20 On rear axles with starting torque compensation, if removed:
- Mount brake hose.
- Bleed brake system.
21 Remove vehicle jack or pitlift and top.
22 On rear axles without starting torque compensation mount caliper with new locking plate or self-locking hex bolts. Tightening torque of hex bolts 90 Nm.
23 Fill rear axle housing with oil up to level of filler hole.