Checking and replacing the center bearing (BMW 5 Series E28)

Examination

The center bearing consists of a ball bearing assembly surrounded by a rubber cushion. The bearing assembly is pressed onto the rear end of the front section of the driveshaft and secured with a snap ring. The center bearing is protected on both sides by dust caps, but water and dirt can still get into the bearing and destroy it. Vibrations from the driveshaft can also cause the bearing to fail. In order to thoroughly inspect the center bearing, the driveshaft must be removed (see section Removal and installation the propeller shaft). Conversely, every time you remove the driveshaft for any reason, take the opportunity to inspect the bearing. Rotate the bearing and check how freely it rotates. If the bearing rotates with difficulty, or there is a feeling that sand has gotten inside, replace it. Also inspect the rubber cushion. If it is cracked or worn, replace it.

Replacement

1. Apply alignment marks to the front and rear sections of the driveshaft.

2. Loosen the screws and remove the clamping sleeve, then separate the driveshaft sections. Remove the rubber bushing, washer and clamping sleeve from the front driveshaft section.

3. Check the condition of the rubber bushing of the spline coupling. If it is torn or cracked, replace it.

4. Remove the center bearing retaining ring and dust boot.





5. Using a puller, remove the bearing assembly.



6. When installing the puller on the center bearing assembly, make sure that it pulls the hub; if it pulls on the outer ring of the assembly, it can cause the rubber to rupture, which will require replacing the entire bearing assembly.

7. If it is necessary to replace a bearing or support, the assembly will have to be taken to a car service workshop, since a press is required to disassemble and assemble the bearing and support.

8. Make sure the boot is still on the driveshaft, then press the center support assembly onto the shaft until it is flush with the boot.

9. On models with a driveshaft equipped with splined sections, install the clamping sleeve, washer and rubber bushing onto the front section of the shaft. Lubricate the splines with molybdenum disulfide grease, then assemble the driveshaft. Make sure the marks are aligned correctly. Do not tighten the clamping sleeve until the driveshaft is completely installed.

10. Install the cardan shaft (see section Removal and installation the propeller shaft).

11. On models with a driveshaft without splined sections, apply a special locking compound to the threads of the driveshaft crosspiece holder mounting bolt, then tighten the bolt to the required torque.



12. On models with a splined driveshaft, tighten the clamping sleeve to the required torque.