Transmission, Manual

Pilot Bearing Removal, Damaged Bearing

Pilot Bearing Removal, Damaged Bearing

>I have finally decided to operate on my noisy clutch and found the pilot
>shaft bearing totally eaten up. All that remains is the bearing race in
>the crankshaft. Does anyone have any good ideas regarding removing the
>bearing race from the crank without tearing up the crank?

Some possibilities:

1) Buy, rent or borrow a bearing puller. This will have internally expanding jaws that will go inside the bearing race and grab it for extraction. (Easy, if you can get a short extractor.)

2) Cut the race in two with a diamond cutter in a Dremel-type tool. (Messy!)

3) Find a short metal rod that is a good fit in the bearing race. You want as close to a slip fit as possible. Pack the cavity in the end of the crank with the thickest grease that you have available, trying to eliminate all air pockets. Put the metal rod in the race and hit it with the biggest hammer that you can get in there, The grease will hydraulically drive the bearing race out. Clean the cavity, and install the new bearing. (Works, cheap.)

4) Replace the crank with a stroker. (Most fun, but a bit more money and effort!)

Wally Plumley
928 Specialists

Wally's #3 won't work in your case since the center is punched out. This leaves nothing for the grease to lever against, though we'd all like to watch you wack the shaft and cover yourself with grease ;-)

Wally's #4 is definately the best bet.

I had this happen also. To get it out I made a makeshift puller consisting of a nut with a couple of tangs welded on it. I slipped the nut sideways through the bearing, then straightened it out so the tangs can grab the MINIMAL amount of shoulder on the bearing. I then screwed a bolt into the nut until it bottomed on the crank, and then continued tightening to force the bearing out.

Just as an FYI, the cause of my bearing failure was a failed Torque Tube. The driveshaft crept forward an inch and a half and punched the pilot bearing's guts out. Here's hoping yours just failed from old age.

Marty Minnich

Actually, it will still work. You will have to hit it harder, because the surface area of the rod is larger, and the surface area of the race is smaller, but it will still work.

If you use really thick grease, such as "wheel bearing grease" (which should NEVER be used in a wheel bearing!), and a well-fitted rod, there is very little grease splatter.


Pilot Bearing Explosion:

Traveling down the road, keeping it under 4K due tovibration there, but not babying it either. Have had
marble sound coming from tranny area when put in gear for last two days. Sounded like throw out bearing
going south (from prior experience). Suddenly, that 4K vibration is all over the RPM range!

Had it flatbedded to the mechanic, using my two tow hooks (extra one from 928 International - Thanks!).
Upon disassembly, my mechanic, Leo, tells me my pilot bearing "exploded". I was going to have him look into my 4K vibration, eventually. He said some people don't change the pilot bearing when they do a clutch job because it is a pain to get to. Thinks it MAY have been the cause of the problem.

I'll post whether the 4K vibration is finally gone when everything gets put back together on Tuesday.

Carlos Herr Nandez
86.5 928 S 5-Speed, 150K
Gran Prix White / Black Leather

Happened to me last year at a stoplight. Lots of vibration as clutch was engaging and until clutch was fully engaged. Clutch disk was "loose" and no longer properly centered, actually drove it a short distance
home this way. Additionally due to the excessive axial runout, the front driveshaft clamp was starting to hit the corners of the guide tube mounting bolts.

What happened was the pilot bearing came apart and the ball bearings were expelled from their races. The inner race was very hard to get of of the pilot shaft and the outer race could only be removed from the crankshaft snout by grinding a section out of the bearing using a Dremel Moto tool.

Tom Robertson
'87 928 5spd.

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