spud72

I see.

I suspect that Chinese bearing company has some sort of an internet spider to scour part #s just to create web pages offering them. Even if the Chinese would make that bearing, I can't imagine too many people here would want to be guinea pigs for it.

The proper Schaeffler/*** bearing is OEM. I got that info right from the company that makes the bearings for them. It's going to be a Porsche only bearing until Porsche relinquishes control of it or someone reverse engineers it as I can't imagine Porsche or *** are going to give specifications for it which isn't simple as there is a lot more to a bearing than boundary dimensions.

I don't see readily accessible substitutes working for it either without modification and best guesses.

These links were shortened so I can't read them. I'm curious to read about these being used as axle bearings.

Porschetech3

The bearings that have been mentioned that are being used as wheel bearings fit various Honda older Fords some Volvo ect. They have the same dimensions and are dual row angular thrust type bearings just like the Porsche trans bearings , but the difference is the wheels bearings are split inner race . The inner race is "squeezed" by the axle nut to produce the desired preload. The Porsche trans bearings are split outer race that is "squeezed" by the retaining plate to produce the desired preload. Also the Porsche bearings have a "notched" outer race for select fit shims.

The chinese bearings are the wheel bearing design (split inner race) that are very plentifull and have been around for a long time. I have no idea why the Porsche bearings have the same identification number as the wheel bearings except that they are dimensionaly the same, but the differences make them non-interchangeable.

Schnell Gelb

Great info. I had seem the inner/outer split story before but did not grasp the significance. Thank you

Porschetech3

I just had a revelation that could result in a interchangeable bearing solution for the upper input bearing. The upper input bearing part number 99630280700 does not have the "notch" in the outer race like the lower pinion bearing 99630280800 does, so the only other caveat is the split outer race. A pair of single row angular universally matched or precision matched (DF-X) for preload, mounted in the" X" configuration ie. face-to-face (instead of back-to-back like a wheel bearing in the "O" configuration ) would be a suitable solution. Just decide if you want them sealed or open. Spud72 should call his contact at *** and see what a pair of universally matched 7207 or 6207 35x72x17 bearings could be priced at.

am

We already studied that solution but unfortunately it came a few dollars away from the price of OEM bearing so I decided that I would'nt risk the success of the rebuild only for a few bucks.

Porschetech3

Right... If there is not a significant savings them the OEM is a better decision.

spud72

It's not that simple. Angular contacts have specific contact angles and without knowing how that the OEM bearing is built as I would certainly not recommend a simple pair of 7207 in their place.... and certainly not conrad 6xxx deep groove bearings.

If you can't get the right bearings, don't make do. It would be different if their certainly not available anymore and have to make something work, but it's not worth it at this point in my opinion.

Porschetech3

Your Right !! I forgot that the 6207 was NOT an angular contact bearing, Its just a plane deep groove ball bearing.

I would never suggest making do, A pair of quality 7207 with matched preload and Identical contact angle ( usually 30 degrees or 40 degrees on manual trans thrust bearing) would be a viable alternative. I would use it in my personal car IF there were substantial savings. I probably would not use it in a customer car .

Schnell Gelb

You guys are amazing - you never give up. I love how you keep trying to find better solutions to this bearing challenge. Thank you.

spud72

That's part of the problem though, without an OEM drawing or an analysis of the bearing, who knows what the proper contact angle of the OEM bearing is. Would it work with the improper angle? Sure, but for how long?

Furthermore, it is giving up on the sealed aspect of the bearing which I assume is something you're willing to do but if not a sealed angular contact like that is not a common critter. Is that a problem for this? I don't know.

Either way, it's sort of an intellectual exercise more than anything at this point considering the proper ones are still available.

Schnell Gelb

Removing the seal on the bearing
A very talented Forum member (now works for Singer)who worked on this issue some years ago removed the seals and some later Posts indicate the same strategy.
The conclusion was that it was worth the risk. The underlying assumption was that the unsealed bearings would last longer than the usual 80k+ miles for the factory-greased and sealed version. Who knows?

Coltti

Hey guys. Great thread! Thanks Nick.

I have a -99 996 C2 which has a whining manual transmission 199000kms driven.
All the symptoms match to a broken pinion bearing.

I did some digging and found out that Audi uses pinion bearing with same measurements and even split outer race as Porsche. I do not know if it has a notch for the shim though... Does anyone have a picture of that notch in Porsche bearing?

Number 4 in the picture: http://audi.7zap.com/en/rdw/audi+a6+.../3/311-311070/

Audi part code: 0a3 311 133

Price for that bearing here in Finland is around 140€uros.

This might be worth checking out!

am

Check my thread : https://rennlist.com/forums/996-foru...nt-my-diy.html

You will find photos of the pinion bearing

europorsche914

Looks pretty similar to me!

https://www.ecstuning.com/b-genuine-...ing/0a3311133/

am

And less expensive