Torque tube rebuild

dlknight · Jun 19, 2022

I'm part way through more restoration work on the turbo and as I now have the torque tube removed so I can tackle the RMS, I'm considering if I should get the torque tube rebuilt?

I've spun the torque shaft by hand and there does not appear to be any play or grinding but there is some noise (kind of like a skateboard wheel when spun). Could this be indicative of dry bearings? Is this normal or are rebuilt torque tubes totally silent?

Next question is if I did rebuild I've heard the C5 bearings that Porsche originally used are not available and that C4 should be used. I've also seen the super bearings from the US but they are pretty expensive! Possibly £1000 after taxes and customs duty for a set of 4....

Kongsodoken · Jun 22, 2022

Been a long time since I rebuilt mine

I used the super bearings they are expensive but very good quality you only 3 off them not 4

I went this route purely because I wanted to ensure the shaft wasn’t rotating in the bearing as I had heard some reports about the bearing insert wearing the shaft [

]

I do remember it being a very satisfying job to do for a non mechanic like me [

]

Eldavo · Jun 22, 2022

Augment Automotive do the kit to refurb it yourself for £40 here: https://www.partsforporsche.co.uk/home/368-porsche-924s944-torque-tube-bearing-rebuild-kit.html#/52-torque_tube_bearing_type-924_and_928

Or they’ll do it for you for and repaint it for £500 here: https://www.partsforporsche.co.uk/944-transmission-axles-and-steering/346-porsche-944-torque-tube-refurbishment.html#/46-painted-yes

dlknight · Jun 23, 2022

Thanks both - off the shelf bearings appear to be the 6006 2Z (or ZZ) C3 ones from SKF or FAG (reusing existing bearing carriers) - less than £10 each

Augment have a more expensive kit for late model 944s for some reason (approx £70).

If it isn't too difficult I may give it a go myself if it saves a few hundred pounds which can be spent on other parts!

@kongsodoken - did you use the threaded bar method to remove and install the bearings?

Kongsodoken · Jun 23, 2022

Yes threaded bar to remove

used high temp silicone as a lubricant and adhesive to push bearings in

then I built a wooden jig and used the scissor jack to push the shaft though the bearings

the jig was 3 6”x6” pieces of MDF with central hole that kept the shaft perfectly aligned.

I was using super-bearings.

I’m guessing you may need to get the bearing inserts made They are bound to be brittle and crack there is a drawings of sizes on Clarke’s garage

dlknight · Mar 31, 2023

I ordered -

[ul][*]16mm Threaded Bar[*]10 x M16 full nuts[*]5 x M16 Form G washers (17mm x 50mm x 3mm)[*]125mm x 125mm sheet of mild steel (3mm thick)[*]16mm blacksmiths drill bit (stepped)[/ul]Traced the bolt holes at the engine end of the torque tube carrier onto the metal sheet and drilled out one at each corner. Then drilled a central 16mm hole in the sheet to pass the threaded bar through. Followed the instructions on Clarks Garage, I used an old hand sanitiser bottle to apply a line of engine oil to the threaded shaft for lubrication. After this I squirted neat fairy liquid at each end and a good amount through the shifter bracket mounting holes, then also sprayed a soap / water solution into the tube using a small spray bottle. Then used my electric impact wrench and it pulled the bearings out in a few minutes! [s2]

Used some blocks of wood to step the metal sheet away from the torque tube flange when the bearings got to the end.

As you can see most of the grease has come out of the bearings, 2 were quite dry and noisy, 1 not so bad and 1 still felt OK. Looking at the inner sleeves for the drive shaft I think two of them have cracks in but are still solid. I have the earlier type bearing carriers that are stamped together, the outer rubber doesn't look too bad (the pictures look bad as they were covered in fairy liquid and grease).

Got some new delrin bushings and rivets from Augment Automotive and made a start on filing down the rivets to fit in the bearing carriers. The rubber outers for the bearing carriers are reusable. I managed to get 4 new SKF 6006 2Z C4 bearings from bolton bearings on ebay for a good price. As you can see the original bearings out of the torque tube were also C4 made by INA, I've seen reference to C5 bearings on rennlist but not sure where that information perpetuated from as mine are clearly C4. Also picked up a pilot bearing while I was at it (6202.2RSR from FAG).

Cleaned up the inside of the torque tube with some white spirit on a home made pipe cleaner which consisted of an old broom handle, empty plastic drinks bottle of the appropriate diameter and an old chamois.

Assembled the bearing carriers with the new bearings and the rivets which I spent far to much time filing down to fit inside the recess in the carriers! I got a local machine shop to press the delrin sleeves into the bearings whilst they were doing some other 944 related jobs for me.

Then I fixed the mistake that the powder coating company made and removed all (most) traces of the black powder coat from the rear "bell housing" with some industrial strength paint stripper (that will come in handy later when I strip the clear coat from my brake calipers). Cleaned it up and applied some etch primer (probably too much). Finally finishing with an expensive few coats of Eastwood Aluma Blast aluminium look paint. Pity my local vapour blasting guy couldn't fit it in his cabinet...

And remember folks safety first - a lot of these paints and chemicals are very toxic!

Next up is inserting the bearing carriers back into the tube and finally the shaft

scam75 · Mar 31, 2023

Great work! I'd love to get this done, probably the last drivetrain job remaining on my car. To be fair, mine seems quiet enough for the time being.

Weekend at your house David when I finally pull the trigger..................[

]

Stuart