GlennD

Merlin,

Pictures. You can see the pinch bolts done up (you will need to trust me on the rear pinch bolt). The bearing sticks out a bit and the shaft appears to fit in fine.

I still have to mark it and pull the shaft out to see how much is in the bearing. Somehow ... I just think that bearing should be seated all the way in.

Glenn

GlennD

Status after a bunch of work:

Replaced the clutch, the throwout bearing, the pilot bearing, the guide tube and had the flywheel resurfaced. Just finished putting the car together to see what I ended up with.

So ... the vibrations are much less but still there. If I push in the clutch and wait for the torque tube to stop, there are no vibrations. Let the clutch out and they come back.

So, now it points to the torque tube. This is great - I have a set of Constantine's super bearings I am dying to install.

Anyways, the pilot bearing needed to be flush (versus what I found) - as per the WSM described. I took the intermediate shaft and played around and I have just the right amount of "end" now sticking into the pilot bearing. It was incorrect before - only part of the raised end of the intermediate shaft was in the pilot bearing. I am thinking that was partially the cause of the vibration.

So ... now it is just to drop the exhaust (again) and pull the torque tube - should not be too bad.

Based upon some of the other work that was done on the car, the "shop" (name not mentioned) messed up the torque tube installation somehow resulting in the bearing moving or the resonance damper not in its correct location.

Feeling much better about this now. (Clutch in, the engine is so smooth throughout the RPM range - nice)

Sean, sorry but I found nothing that will help with your search of the vibration on the car you are working on.

Cheers
Glenn

Mrmerlin

when your TT is out before you remove the drive shaft, spin the shaft a few times and observe the ends see if maybe you have a bent shaft ,
otherwise when the shaft is out roll the shaft on the floor or other smooth surface to see if its bent.

GlennD

Excellent idea ... I would feel pretty foolish putting in new bearings on a bent shaft

Cheers
Glenn

GregBBRD

First time I've looked at this thread....and I didn't read every post carefully....but I didn't see any mention of the front torque tube bearing migrating or the shaft being loose in the bearing

This is the usual problem with a vibration as severe as you are describing. I've seen them shake so badly, they will shake the wire out of the air flow meter!

There's actually several of clues that this is your problem....If you look at your picture of the driveshaft to clutch shaft coupler, you can see a ring where the paint is removed. With everything being correct, this is not possible without torque tube "whip". The second clue....If I understand what you found in your clutch inspection, the guide tube for the T/O bearing was broken....that would be from the coupler hitting it. Your third clue is that pilot bearing....if there is driveshaft whipping, the pilot bearing is absorbing a whole bunch of abuse.

If you find that this is the case, you will need to replace both the torque tube shaft and the clutch shaft....they have been through hell.....not to mention the coupler....that's what is whipping around.

And do yourself a favor...order some new coupler pinch bolts. That front one looks pretty well rounded out.

GlennD

Greg,

Thanks. Now that I look at the picture of the guide tube where you pointed out, yes it does seem obvious. (Humm ... good visual point for the files)

From the amount of flex I had with the drive shaft in the tube tube, I am thinking that the front bearing migrated towards the rear. Unfortunately, this is my first stray into the part of the car so I had no reference or experience to draw upon.

The guide tube was not broken ... I thought I found something in the race - but when I compared to my new one, it was fine. I did recant my comment in a followup post.

I believe I caught this early ... the pilot bearing was still very tight and everything looked good when compared to new. I am very critical on parts replacement. Parts are cheap ... the shoulder and back pain associated with replacement of parts - often priceless.

And yes, those pictures are prior to my replacements. All the bolts on the coupler (including the rear) are now new. To go through the effort of pulling everything apart only to reuse bolts that see stress would not be smart

If the torque tube drive shaft did whip (sure looks like it may have bounced a bit from the guide tube picture), I am going to imagine that the drive shaft is not something I want to reuse. Probably smart to do a replacement now.

Thanks Greg for stepping in. Your comments are always appreciated.

Glenn

WallyP

At this stage, I would contact Constantine to see if I could trade the new bearings in on a rebuilt tube. Unfortunately, he is in the middle of moving up here to God's Country, so he might not have a tube handy...

Black Sea RD

Unfortunately Wally is correct, we are currently closed and can't provide a rebuilt TT at this time.

I'm sure 928 Intl or 928sRus can though.

Best regards,

GlennD

Thank you Constantine for your reply. Hope your move goes well.

So here is a potential dumb yet curious thought. I expect my front bearing migrated towards the rear. That is why I may have a wet noodle for a drive shaft. If I confirm this to be the case, what would happen if I put one on Constantine's super bearings in and pushed it into the correct location? I should be able to do that with only removing the clutch again and leave the torque tube in-situ.

Downsides? Versus this may never have been done before. One extra bearing in the correct location. The drive shaft just needs to be straight so an extra bearing should help.

Thoughts?

Thanks
Glenn

Black Sea RD

Hi Glen,

The front TT bearing moving rearward is a common malady, especially with 5-speeds.

We did help another Rennlister with the same type of problem by selling him a refurbished OE TT bearing which he placed at the front of his TT as you describe doing instead of rebuilding it fully. Last we heard it seems to be holding up well for him.

Although we would advise to just rebuild the TT with all new Super Bearings, given our current situation, this could be an alternative for you to try.

We might be able to find a good used OE bearing unit in our stash we could refurbish for you which would be cheaper than selling you a Super Bearing.

The main concern would be if your drive shaft is still usable or has it been bent.

HTH,

the flyin' scotsman

hi Glenn.....we know the 'shop' that did the previous TT left off some steps so all else being good its probably worth a look. I don't recall if there was history wrt the source of the new TT?

Given we checked the motor mounts from above did you check them and the gearbox mounts from below. Their condition is very fresh for me so could swing over and look......let me know.

OTR18WHEELER

In response to the adding another front bearing question, this was the method I used to resolve my vibration caused by the rearward migrating front TT bearing.
Constantine supplied a OEM bearing he pressed into a used OEM race.
Although this was initially only intended as a temporary solution, I have since put about 8K miles behind me with no Ill effects. Although an unorthodox fix, it has worked out well.

GlennD

Hey great - thank-you for the feedback. Glad to know I have an option until I get around dropping the complete torque tube. I have a note to Constantine to see what he has for OEM style bearing that I can use/purchase.

Seems you still need to drop that torque tube at the clutch side - to slip out the coupler and slide in the new bearing.

Can you please share how you installed the extra bearing with the torque tube still in the car? (I am assuming you did not remove the torque tube to install this extra bearing).

Cheers
Glenn

Speedtoys

I had a mystery vibration, until I was forced to replace my front pullys and dampener because of a bolt coming out up there and ruining them...

I'm betting I had a going-bad damper.


But that's just me experience.

OTR18WHEELER

I dropped the TT, but I had to replace a broken flex plate also.
I have a thread titled growling sound, I don't know how to link it using my phone.