Replaced clutch disc - now I'm burning it up !

[gg30]

I own a 1971 240z and this past winter I swapped out the trans that was in it (datsun b 210) with the original z trans. The PO told me the original had been overhauled and he never got around to putting it back in. To make a really long and agonizing story short, the z trans was no good and I ended up putting the b 210 back in. But while I had the trans out I decided to replace the clutch disc and the throw out bearing. Easy job. But now when I drive the car, I get a wicked burning smell like I'm smoking the clutch. My guess: old flywheel and new disc aren't happy together. My question: should i just ride out the rough honeymoon and eventually they will have a happy marriage, or do I need to do something more drastic??

[IdahoKidd]

I'm having clutch issues too. Pulled it out 5 times last weekend. Some of what you smell might just be oil residue left over from the swap and it will go away in a short while. I discovered (among other things) that my brand new throw out bearing seized almost instantly and it was burning it self up. Does it smell lot hot brakes? Like hot grease/oil? Or like a hot bearing? The last one you would only know if you smelled it before, it will never go away. If everything is engaging and disengaging correctly, and there isn't a slippage, it is likely it is just the assembly grease and will clean it self up in a dozen stop lights.

[gg30]

It smells like brakes that are seized. I've driven it probably 20 miles or so, stop and go, with no less odor. I also noticed that its worse when i going up a steep grade in third or fourth gear. But I don't feel any slippage really. The worst was when I was on the highway...and when I first discovered the problem. Went about 2 miles at 65 mph and wow it reeked.

[IdahoKidd]

I'd guess, based on my experience last weekend, that the throw out bearing isn't fully disengaged from the disc and as such continues to spin and is or has burned itself up. Does the rod from the slave cylinder have adjustment? Some are fixed and some are adjustable. Either way, their should be just a hint of slack in the arm and the rod. If there isn't, it means the bearing is too tight. There are two differnt collars on these cars, but since you kept the same collar each time (assuming you did?) that part should be correct. There are at least two different pressure plates available too I discovered. My pressure plate came wrong and won't allow it fully disengage. It isn't possible to tell with it in the car, but setting side by side, one has a concave surface and the other convex. It makes about an inch difference where the throw out bearing contacts the diaphram. It is possible you have the convex pressure plate and it is riding the bearing. Check the tension on the slave rod first. If it is really snug, (and not adjustable) drop the slave off the side of the transmission and see where the throw out arm rests. IF it is the issue with the pressure place, it could also mean it isn't fully disengaging and allowing partial slipping, which makes that hot brake smell.

I feel your pain, I still haven't gotten my issue resolved. Too much misinformation

[gg30]

Well the slave does have an adjustment and that's been looked at. I originally adjusted it according to the Haynes manual..it seemed perfect as far as position on the pedal..then when this issue arose I went to each extreme: really high pedal and really low pedal...no difference. In response to the pressure plate, I didn't change it at all during the trans swap so it should be the right one. I am wondering about the arm sticking though. That would make sense and would most likely cause my burning odor.

[alternativez]

Any debris or oil or even any type of moisture or dust in or seeping out of the bottom of the bell housing which could indicate a cause? Such as a leaking or damaged rear crank seal or rear oil pan gasket? If you did notice it more on an incline, it could be pressure plate slippage due either to throw-out pressure or to a soiled pressure plate. Good luck!

[IdahoKidd]

Hey gg, any luck on finding out what happened? I pulled mine again today and discovered that it was a manufacturer defect. The ends of a some rivets had not been ground down and wouldn't let the pressure plate seat against the disc. It was nearly a quarter inch out. Replaced it tonight and all seems good. Hope you find a solution/cause. Do let us know.

[gg30]

Well unfortunately I have yet to crawl under there and explore some ideas we've discussed. One thing I was thinking about was the fact that I replaced the old dried up rubber boot where the throw out arm comes out and connects to the slave. I'm wondering If maybe it is somehow keeping the arm from traveling all the way it needs to and therefore keeping the disc somewhat disengaged from the flywheel. I may take it out and see if I can see a difference. Hopefully this weekend.