bkingdon

When I pulled my TT I found that the front bearing had moved way forward and was no longer tight in the tube. I installed 3 pointed end allen grub screws with blue loctite to hold it in the correct place after the bearings were replaced. Time will tell if it is a permanent fix.
Also, my '87 auto had the groove in the end of the shaft so I bought the parts from 928I to add the shims and clip that was used on the earlier models to prevent the flex plate movement. One TBF is quite enough for me!

Brian K.

Black Sea RD

One thing to keep in mind when pinning the bearing carriers in place. The bearing is press fitted into a stamped steel piece. There is nothing keeping the bearing in the bearing carrier except friction. If a method is used to stop the bearing carrier from moving then the forces causing this migration (vibrations, driveshaft twisting) can possibly act on the bearing itself. This will cause the bearing to walk out of the bearing carrier.

Constantine

Dwayne

THANKS for the replies, all. So it seems the bearings are not that far back and not a critical issue to address for now - especially since I'm not noticing any noises or vibration. I'll keep monitoring the situation and put the TT down near the bottom of the list of things to replace/fix. THANKS again!

Vilhuer

Which if any automatic tubes have 3 bearings from factory or are yuo taking about rebuild tubes only? Few fairly late 28mm new before opened versions I know have all had only 2.

There are two completely different carrier versions. Common one has this problem, bot 25mm and 28mm version. Much less common version which is made from two (bare metal visible) similar halfs are riveted together and this makes sure bearing can't go anywhere. I have no idea in which all TT's Porsche used these. Only have seen them in two S4 automatic tubes. Other S4 tubes have had normal rubber coated single side version so double sided setup might have been temporary thing.

Black Sea RD

Hi Erkka,

A double sided/riveted version was primarily used in 944 torque tubes. Interesting that Porsche made a few of them for the 928.

The 944 torque tubes are longer but are smaller in diameter so the 944 bearing carriers will not fit in the 928 torque tube in case anyone was wondering.

Cheers,
Constantine

Vilhuer

I have seen similar setup also in 924 tubes. These 928 parts clearly were designed to correct diameter tubing and I don't think they were 944 variants modified to fit into larger tube.

Black Sea RD

Yes, the 924/944 cars had many crossover parts, especially in the beginning.

Bill Ball

As I recall, Erkka used some large diameter PVC pipe cut to length to fit in between the carriers. This accomplishes the same thing as set screws, also not restraining the bearing itself from moving. I wonder if his bearings have walked out of the carrier. If the bearing is able to drag the carrier along the tube, it must be pretty snug in the carrier. You'd think the carrier could be peened to retain the bearing anyway.

Vilhuer

Mine are not going anywhere. They are still on work table and empty TT is in corner waiting to be put together. Relatives '78 TT has nylon rings bolted to TT wall at both ends next to first and last bearing, PVC pipes which have rubber clued into ends in between bearings and bearings that are glued into carrier to prevent them from moving away from carriers open side. No problems what so ever so far and we don't anticipate any.