Defective clutch?

I just had a mayor clutch repair on my 1988 XJ Pioneer (4.0 Renix engine). I bought tne LUK clutch kit, and I know for sure that the flywheel was resourfaced.

The clutch normally behaves great, it cuts in the lower half of the pedal travel, but that should be normal due to resourfacing, it really doesn't bother me.

What is really annoying, is that when I drive steep hills (those where the engine temp doesn't go under 210 even if you have the electric fan on), or when I drive in heavy traffic, the pedal starts tu cut in a higher position, and the pedal also gets harder. If I keep on driving, the clutch will eventually start slipping.

When I start driving faster (let's say flat highway) the clutch will eventually start cutting in a lower position and get softer again. The same happens if I park and wait for a time (let's say at least one hour). I brought my XJ to warranty, and I'm being told that it's probably due to a defective clutch, so I will probably have to request warranty for it.

Now my question is if anyone has had a similar espeirience? I realy trust the shop as it's from a friend of mine, the reason I'm asking is because manual XJs were never sold in Mexico, so the few you can find around here are imported from the US, so it's a really rare version; that means most shops really know how to repair XJs in Mexico, but really few have experience changing clutches on these rigs, and I know they are kind of tricky regarding clutch repairs.

Regards

Having the flywheel was resurfaced will not change engagement point.
Your clutch is slipping and getting hot, check your free play the clutch should start to ingage 1/2" from the bottom and have 1" free play at the top.

Well, the problem is kind of backwards. When everything has rested overnight, the clutch is definitively cold and it engages strongly, just as it should. It works great as long as I don't force my XJ, let's say long steep hills or heavy traffic, normally on hot climate but as it's lately always quite hot here I just cannot try it in cold climates. When this happens the engagement point starts to go upwards, let's say normally 1/2" from the bottom, it will eventually go to 3/4 and further until it starts slipping. The pedal will also get harder, but the strange is that this disappears as soon as I start driving faster (the engagement point will drop again to normal and the pedal will get soft again). Having that said, it doesn't get hot because of slipping as it normally engages just as I would expect it, it's on "extreme" conditions when it starts making trouble. The old clutch was not an original one (it was a rebuilt one) and it didn't do this, and it was quite worn out.

This is a typical symptom of a worn clutch, but this one is a new, original LUK one, what's wrong here?

How bad is your oil leaks then, is oil getting on it?

I have corrected oil leaks. Do you think that could cause this? The crank had a leak direc to the clutch, but it was fixed, my only oil leak as far as I see and notice is on the valve cover, the stupid oil cap just doesn't stop leaking. I made a gasket to see if it stops leaking, but I did this just yesterday...

schmiedel said:

I have corrected oil leaks. Do you think that could cause this? The crank had a leak direc to the clutch, but it was fixed, my only oil leak as far as I see and notice is on the valve cover, the stupid oil cap just doesn't stop leaking. I made a gasket to see if it stops leaking, but I did this just yesterday...

Click to expand...

A valve cover leak on the back over the bell housing certainly could.
While your at it check and make sure the bell Housing bolts are still tight.
It sounds like OIL is still getting on the clutch

Well, and it could be caused on steep hills, this causes the oil to get to the back and leak down... I really hope you're right, this will make things quite easier. I will have to buy a valve cover from a +/- 92 XJ, the one from Renix engines really sucks, the oil cap never seals properly. However, if it starts slipping, will it cause the pedal to get stiffer too?

Just a guess....sort of...

Flywheel resurfaced? NO NO NO

replace flywheel.

Rev

Well, where can I get a flywheel? Here in Mexico it will be nearly impossible. Any ideas of US distributors that sell it and will send it outside US? Or is it the same flywheel of a YJ or TJ?

Regards

Hell there all made in Mexico

That really pisses me off, I just bought myself a Go-dan 3 row radiator, paid 100USD for damn shipping, and it results that it's made in Mexico... You know who sells these parts in Mexico? Nobody, they're made for US market and you will not find them at any local store, it's really crappy, the manual tranny XJ was never sold in Mexico (only auto version), so you will never get specific parts for this model here.

But well, the shop just told me it's possibly some adjustment issue, it's really strange as the pedal gets kind of hard, and it's really soft when everything's cold, so that's really weird as a bad flywheel could cause slipping but wouldn't really change the pedal stiffness, at least it sounds logical this way...

I think its getting hot and causing the throw out bearing to hang up some.

Yes,

The problem was related to that. There were adjustments made without dropping the transmission (clutch line relocation to start with) and now it doesn't slip anymore (just never), but the pedal still gets stiffer and higher.

Do I need to replace some other stuff inside the clutch assy?

BTW, I have some more writeup.

Found out that all the clutch line was a rubber / plastic line, similar to the brake lines. This line, if it sits close to the muffler, just gets hot, expands and causes some weird pressure behaviour on the clutch. I am not sure if all XJs come with this line, but replacing it by a 100% metallic line (or at least by a new one) avoids these changes that can cause abnormal behaviour on the clutch pedal.

schmiedel said:

BTW, I have some more writeup.

Found out that all the clutch line was a rubber / plastic line, similar to the brake lines. This line, if it sits close to the muffler, just gets hot, expands and causes some weird pressure behaviour on the clutch. I am not sure if all XJs come with this line, but replacing it by a 100% metallic line (or at least by a new one) avoids these changes that can cause abnormal behaviour on the clutch pedal.

Click to expand...

Metal is a better conductor of heat and may make that problem worse. I have the stock plastic tube and have not experienced that problem but here's a suggestion to test that theory ... tape a piece of insulation around the tube and see if that problem goes away.

For the main issue posted here, I'd suspect oil got onto the clutch.

Well, I am not yet getting rid of the oil theory, my clutch now works great, never does anything strange. If it was oil, why would the pedal get stiffer? With oil I would suspect the clutch to be slipping, but no direct effects on the pedal, or am I wrong?

I had all the gaskets replaced, I still have an oil leak on my valve cover (will replace the valve cover as soon as I find one from a 1992 or similar XJ). It kind of leaks everywhere, but when I unscrew it, it looks a little bent on some places, so that must be the reason.

Regards

Langer, I am going to have to disagree with you on your assertion that the engagement point does not change when you resurface a flywheel.
Given the internal slave system, it takes a finite amount of fluid to force the piston a given distance. If the distance is increased it takes more fluid. To get more fluid displacement, the pedal needs to be pressed further. I had this exact issue when I resurfaced my flywheel. There are two methods to correct it. You can go to a higher displacement master cylinder (what I did) or you can fashion a shim to go behind the slave cylinder.

Now back to the issue of the changing clutch action. My best guess is that there is either some moisture in the fluid or some air in the system. Going up a hill generates considerable heat in the engine compartment, especially the exhaust temps. As the temps rise, the air or moisture will expand causing the clutch release. I have seen this in several other vehicles in the last 30 years. The simple thing to try to make sure this is not the case is to completely flush the system and do a good bleed on the system. Personally, I have found that bleeding the clutch is a bitch. I have an electric vacuum bleeder and the reason is because there was no other way to get clutches bleed without a tremendous effort.

Old_Man

I'll consider your comments, my technician told me it was a pain in the ass, and he does it manually. I haven't had any issues in the last two months, it works great now, but it's also rainy so temperatures are not so extreme right now. When we're in hot climate again I'll see if it happens again. Now the question, how expensive is such a bleeder? We have not much information about this kind of equipment here in Mexico, things are often done manually...

Regards