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Replacing Rear Axle Bearing on 356 Disc Brake Cars

September 24, 2010 | Troubleshooting & Repair

 By: Mike Robbins

 

The bearing, universal no. 6306, can be found at most bearing supply houses. It is also used on swing axle Beetles and can therefore be found at VW shops. The large and small O-rings are also used by VW. The axle seal has unusual dimensions and is tough to find outside of Porsche parts handlers. Steps:

1. Remove hub cap.

2. Remove cotter pin in axle nut.

3. Chock wheel.

4. Using 36mm or 1 7/16" 6 point- 3/4 drive socket loosen axle nut.

5. Loosen lug nuts.

6. Jack up side of car and support w/ jack stands.

7. Remove wheel.

8. Jack up outboard end of axle so it is higher than inboard end. Place a secure prop under axle tube, bottom of shock or wherever convenient. This will minimize oil loss out end of axle tube.

9. Using 11mm or 7/16" flare nut wrench loosen the brake line fitting at the banjo fitting on the caliper. Do not loosen the hollow bolt at the banjo fitting. Disconnect the brake line from the banjo fitting.

10. Remove the brake pads.

11. Using 17mm wrench remove the two bolts holding the caliper to the ears on the bearing housing. Set the caliper aside, oriented so that fluid doesn't run out or dirt doesn't get in.

12. Remove the two screws holding the brake disc to the hub. Set the disc aside.

13. Remove axle nut.

14. Remove hub. If it pulls off super-easily that may indicate that the splines on the axle and/or in the hub may be worn. Can cause oil leaks and other problems. To further check this, put the hub back on and check for rocking or other indication of loose splines. May mean axle [big job] and/or hub [little job] should be replaced.

15. Remove four bolts holding dust shield to inner side of backing plate.

16. Study the arrangement of the parking brake mechanism so you'll know how to put it back together in case it comes apart as you perform the next couple of steps. You may want to mark which side of backing plate goes toward front [or rear] of car. It will bolt right up the wrong way and you won't want to do that. Remove cotter pin and castellated nut on end of parking brake cable. Pull parking brake cable housing out of backing plate.

17. Remove four bolts holding backing plate to bearing housing. Carefully remove the backing plate and the attached parking brake components.

18. Remove the inner O-ring from the axle, the washer behind the O- ring and the outer O-ring from the groove at the periphery of the bearing.

19. Now it may get sticky. Using puller VW 241a remove the bearing from the housing. If you do not have the special puller you may or may not be in for a battle. Sometimes the bearing fits loosely on the axle and in the housing and comes out easily by using the appropriate tools to hook in the bearing and pulling it out. Other times the bearing is tight on the axle and/or in the housing and defies efforts to extract it. It is imperative to avoid pulling the axle out more than about 3/16". [It can actually come out approx. 1/2" ...but DON'T try it.] If the axle is pulled out more than 3/16" it is possible for the fulcrum plates to fall behind the inboard end of the axle. This locks up the differential and the only way to fix it is to remove the differential-axle assembly from the car, disassemble the differential and reassemble in correct position. And removing the differential from the car creates the possibility of unseating the differential side bearings. And then you should probably replace the very expensive ring gear bolts. It gets complicated. Over the years many people have worked on the rear corner of Beetles and 356s without encountering this problem. But it can happen depending on the alignment of the axle as things are taken apart and if the axle is rotated while doing this work. Fig. 71 on page R37 of the 356A Shop Manual and Fig. 78 on page R47 of the 356B Shop Manual illustrate the parts.

20. As the old saying goes, "reassemble in reverse order".

21. If applying force to install new bearing, contact face of both races simultaneously. Leave bearing protruding from housing approx. 1/4".

22. Liberally oil new O-rings before positioning them. Position large O-ring over periphery of bearing. Don't forget the washer before positioning the small O-ring.

23. If you're going to replace the seal in the backing plate, now's the time. It's a little tricky to remove the old and install the new without bending the backing plate. Don't meat axe it!

24. Using the four bolts to gradually draw up the backing plate will press the bearing home.

25. Use a blunt tool to push the inner O-ring home.

26. Reassemble the parking brake stuff. Use vise grips to squeeze the expanders together so you can thread the cable through and get the washer and nut on the end of the cable.

27. When fitting the caliper leave the two 10mm bolts that hold it a little loose until you get the brake line fitting started in the banjo fitting. Be careful not to crossthread the brake line fitting...it's easy for that to happen. Don't forget to tighten the bolts holding the caliper.

28. Bleed the brakes.

29. Be sure to tighten the axle nut to 400 ft. lbs. If the slots for the cotter pin don't line up, tighten the nut further.

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