Clutch issues and thunk noise on release

[dn010]

So here is a brief history:

Two years or so ago my clutch slave had a slow drip. I didn't drive the car much so as long as I could move it in and out of the garage I was satisfied. The leak went on for a year or so, no rubber fork boot installed so that liquid went down the fork and who knows where else, ending up on the floor.

Finally got to a point I was tired of this leak, having to constantly pump the clutch pedal when I wanted to move the car so I got the x-ref slave from Europe and installed it maybe a year ago.

For years now when I take off from a start, sometimes the car shakes somewhat harshly if I let the RPMs get low (not reving must before going). If, on the rare occasion I leave the car out in the rain, that shake is even more violent and very loud as the whole car is shaking. I thought about rain water somehow traveling down into the clutch area since I don't have the protective boot there being a possible cause. Also when I'm staring off from a stop, I hear a clunk coming from the clutch area when I release the pedal, louder if I release it faster, not as bad when slow.

The current clutch isn't that old but has seen some abuse especially with tuning timing under load (EFI). I've had worn out slipping clutches before and this is not it - the engine doesn't rev up while I go no where and then suddenly catch, so I'm not sure if the rain or old dripping fluid is causing this issue or what.

I suppose my question is, do these issues sound more like clutch issues or can it possibly be an internal transmission issue? A few months back I was able to grab a clutch kit for only $100 and if I need more than that to fix this problem I'd like to put an order in to take care of this.

Cheers.

[DMC-81]

This sounds like a clutch to flywheel friction issue (perhaps rust/dirt/clutch fluid impacting proper adhesion). It's hard to tell until you have it apart to determine the condition of the related parts, but I would plan to check/do at minimum:

- Check clutch fork for excessive rust, especially the spring holder that attaches it to the pivot ball
- Replace the missing fork boot
- have your flywheel professionally re-surfaced (~$100)
- grease the pivot ball with 50/50 moly grease and anti-seize
- check/replace the pivot ball cup/seal (Rob Grady has these)
- get a quality pilot bearing (Nachi or similar, $10-24)
- replace the throw out bearing (if it didn't already come in your clutch kit)

Cheers,

[David T]

Since you say the clutch is not slipping maybe it's not a clutch issue. You say it gets worse in the rain, maybe it is an ignition issue. A bad wire or water in a spark plug well.

[opethmike]

I agree with Dana. To me it sounds like that leaking fluid has built up on the surface of the clutch disk or the fly wheel.

[dn010]

Thanks Dana, I'm glad I asked- I forgot about the damn pilot bearing- I will have to order one of those. I bought a new fork boot from Rob a few months ago so I have that, the clutch kit came with the TO bearing so I should be set there as well thankfully. I also have new allen head bolts to replace all the old hex head holding the 'drive shafts' on while I'm in there. Is there a place nearby that you'd recommend for the resurfacing?

I doubt it is ignition or even weather related, I left those problems behind long ago. I'm running EFI/EDIS, I have a shield over the coil pack & MAF sensor and use weather pack connectors for everything. My spark plug boots are definitely protecting the plug wells.

Thanks guys, I'll begin the lovely removal process soon, this will be the fourth time I'm putting a clutch in this car over the span of 16 years.

[Bitsyncmaster]

After just doing my clutch, I think it would be almost impossible to contaminate the clutch with engine oil or clutch fluid. The pressure plate mostly shields the friction surfaces and centrifugal force would keep any oil thrown off the flywheel.

[opethmike]

Thanks Dana, I'm glad I asked- I forgot about the damn pilot bearing- I will have to order one of those. I bought a new fork boot from Rob a few months ago so I have that, the clutch kit came with the TO bearing so I should be set there as well thankfully. I also have new allen head bolts to replace all the old hex head holding the 'drive shafts' on while I'm in there. Is there a place nearby that you'd recommend for the resurfacing?

I doubt it is ignition or even weather related, I left those problems behind long ago. I'm running EFI/EDIS, I have a shield over the coil pack & MAF sensor and use weather pack connectors for everything. My spark plug boots are definitely protecting the plug wells.

Thanks guys, I'll begin the lovely removal process soon, this will be the fourth time I'm putting a clutch in this car over the span of 16 years.


Well, on the upside, you don't have to remove your whole drivetrain to get to your clutch like I do :)

[dn010]

After just doing my clutch, I think it would be almost impossible to contaminate the clutch with engine oil or clutch fluid. The pressure plate mostly shields the friction surfaces and centrifugal force would keep any oil thrown off the flywheel.

I have been following your clutch thread, that is what is making me feel like finally getting under mine and finally getting it done with. I thought it would be impossible too but also know crazy things can happen, especially on the DeLorean. The only time I know for sure I saturated a clutch disc with oil was when I blew a hole in my clutch shaft tube from parts from the blown spider gear spindle. Those were fun times.


Well, on the upside, you don't have to remove your whole drivetrain to get to your clutch like I do :)

Well, at least there is that! Maybe one day.

[DMC-81]

Thanks Dana, I'm glad I asked- I forgot about the damn pilot bearing- I will have to order one of those. I bought a new fork boot from Rob a few months ago so I have that, the clutch kit came with the TO bearing so I should be set there as well thankfully. I also have new allen head bolts to replace all the old hex head holding the 'drive shafts' on while I'm in there. Is there a place nearby that you'd recommend for the resurfacing?

I doubt it is ignition or even weather related, I left those problems behind long ago. I'm running EFI/EDIS, I have a shield over the coil pack & MAF sensor and use weather pack connectors for everything. My spark plug boots are definitely protecting the plug wells.

Thanks guys, I'll begin the lovely removal process soon, this will be the fourth time I'm putting a clutch in this car over the span of 16 years.

You're welcome Dan. Rob Grady sells the Nachi pilot bearing. You should be able to call around machine shops in your area and ask if they resurface stepped flywheels. I use reputation and recommendations for any shops that touch my cars. If you can't find one, I here is the one I used:http://advancedcylinderheads.com/
The Owner Jimmy and manager Donnie are great guys. I would use them again.


The only time I know for sure I saturated a clutch disc with oil was when I blew a hole in my clutch shaft tube from parts from the blown spider gear spindle.

Did you have any after effects of this problem after you repaired it? Like noise, grinding, hesitation, etc? Or, was the transmission basically good until this issue began to appear?

[dn010]

Thanks again Dana. For some reason I thought you were closer to Tampa, I will look around locally and see who can resurface the flywheel.

The spindle blew on a downshift that was made while the car was traveling too fast. It was enough to make the tires chirp accompanied by a bang which was the spindle. I was still able to drive just fine and never would have known what happened if it wasn't for one of the chunks piercing the tube causing oil to go all over the place. I drove it 15 miles or so home this way. Luckily the rest of the other metal chunks settled and did not cause issues. I replaced the spindle, tube and other things in the transmission and it has been fine, sometimes I have an issue downshifting into 2nd but it has always been that way since I've owned the car.

[DMCMW Dave]

I agree with the contaminated clutch disc theory. Dana's advice is right on, just replace everything. This is the ultimate "while you are in there" job. Don't be surprised if everything actually looks pretty good when you get it out, it doesn't take much contamination or flywheel burn to have this effect.

[Josh]

Also here to say it sounds like a contaminated clutch disc. It doesnt take much to contaminate the disc with a leaky slave cylinder. It drips down the fork and right onto the clutch disc.

[dn010]

Thank you all. I need to order the pilot bearing and crawl under to see if any seals are leaking and add those to the order if needed. I'll knock out the clutch replacement after they come in and will update you with my findings.