Replacing Wheel Bearings
on a 1986 930
Neil Walker
neilw86@fuse.net

1. Sir Tools Bearing Remove/Replacement Master Kit B90 with additions/modifications (May be available as a kit variant by now).
2. Large Bearing Splitter and Puller
3. High quality Slide Hammer Bearing Puller
4. Propane Torch
5. Torque wrench up to 230 ft lb
6. 32 mm socket
7. A quality 8mm hex wrench with fitting for torque wrench
8. Conventional small tools

1. The studs on the 930 hub are longer than the standard 911 hub and interfere with the bridge piece of tool part # 3. It is necessary to drill a 5/8^th inch hole on the centerline 2 5/16^th inch from the center of the hole for the #1 bolt.
2. The bearings for the 930 are NOT single piece cartridge bearings of the type the tool was designed for. They are a pair of conventional taper roller bearings similar to those used on the front wheel. Therefore an additional disc is required to press in the outer races of both bearings and press out the outer race of the inner bearing. They can be made from additionally purchased or spare adapter sleeves #9, 10, 11 or made by a local machine shop. The diameters should be;

• Diameter for Removing/Installing disc for the outer race of the inner bearing should be 2.944 to 2.946 inches.

Disc should be of sufficient thickness to apply and distribute the forces necessary for a fairly big interference fit of race to housing.

For each wheel hub being overhauled

• Inner and outer bearings
• Inner and outer grease seals

1. Loosen lug nuts, jack up rear of car and support on quality jack stands, remove wheel(s).
2. Remove spacers.
3. Remove brake calipers and hang from car using wire hooks or similar. DO NOT HANG BY BRAKE HOSES.
4. Remove brake drum/disc.
5. Remove split pin, retaining nut and washer from axle. This nut is TIGHT. I used a length of pipe to act as anti rotation and a big breaker bar.
6. Remove socket head screws from gearbox end of axle.
7. Remove axle, I found that I could remove the drivers side OK but had to undo lower shock bolt to get passenger side axle out.
8. Using the SIR tool as in the instructions Figure A remove the drive shaft.



9. Run the brake adjuster star wheel right in, remove the springs and remove parking brake shoes.
10. Remove the brake activation linkage. That on my car was not per the book but once the brake shoes are out it is a simple linkage to remove and replace.
11. Clean everything up as best you can using your favorite grease removal materials, both outside and inside of housing.
12. Remove outer race of outer bearing (wheel side). Porsche says take off the swing arm and use a special tool in a bench press, not an option for most of us. With lots of care, a long drift a big hammer and some discomfort this can be done from under the car. My procedure is to use the propane torch to get the housing fairly hot, round about 250 degrees F and then use a large slide hammer puller to pull the outer bearing outer race. There is a considerable interference fit on this race and only a small lip to pull on. My car did not have cut outs in the housing shoulder for a three jaw puller so it takes a high quality puller to get the race out. I could not do it without heating the housing. If I had the arm off the car I would make cut outs for a more rugged 3 jaw puller. I used my tire pyrometer to make sure the housing did not get too hot.
13. Remove the outer race of the inner bearing using the Sir Tool and the special extra disc.
14. Clean everything thoroughly using your favorite methods.
15. Now for the hard part. Hold the axle in a sturdy vice and assemble a large substantial sharp edged bearing splitter around the bearing axle interface. Again there is a significant interference fit. I had to use a splitter and a puller to remove the bearing.

1. Lightly grease the new outer races and install them one at a time using the Tool. The races may not bottom out in the housing due to Tool interference. If this happens re install the tool with the old outer races ‘back to front’ and use as press tools to fully seat the new outer races. As the old races will fit inside the housing bore by a small amount you may have to take a soft drift and tap them out.
2. Grease the bearings liberally working grease between the rollers and cage and fill the housing.
3. Put the outer bearing inner race/roller assembly in place and hold in place by pressing in the grease seal. This may be possible by hand or may have to be lightly tapped into place, but keep it square and properly seated.

 



 

4. Re assemble the brake shoes and actuation cable. I put a smear of anti seize on the star wheel threads, you can also put touch on the shoe pivot points.
5. Install the axle using the Tool.



 

6. Install the inner bearing inner race/roller assembly using the Tool
7. Install the grease seal as before.
8. Install the drive shaft washer and nut. Torque to 230 ft.lbs. I used the pipe against to wheel studs and floor to react the torque. I always slightly overtorque, back off and then re torque to the correct value. Don’t forget to approach the required value smoothly and steadily. You may have to slightly overtorque to get the nut castelations and hole to line up for the split pin. Use a new split pin.
9. Attach the inner end of the drive shaft making sure you fully torque the six socket head screws. You may want to use low grade locktite on them too. I drilled the heads of two screws per side and safety wired them just to make sure that they would not all loosen.
10. Re install the drum/disc. I usually trial fit it few times adjusting the star wheel and position of the shoes so there is not too much clearance when finally assembled.
11. Re install the caliper.
12. Install wheel and initial tighten lug nuts.
13. Lower car and torque lug nuts to 80 ft.lbs.