About 11 years ago I got my 1963 E-type from a fellow in San Jose that had recently refinished and other work which included a new clutch. That clutch worked fine until last winter when the throw out bearing disintegrated from the oil leaking from the rear main. My local mechanic who is familiar with these and other sports cars of that vintage replaced the clutch. Initially upon picking up the vehicle I noticed that the clutch worked fine when cold, but as things get warmer it is harder and harder to get into gear, requiring the mashing of one of the synchros to slow the spinning of the transmission to facilitate engaging 1st or reverse. Initially my mechanic thought it was due to aged hydraulics, so I paid him to replace the slave and master. Still the same, rough to deal with when warm. My mechanic tried to tell me this was normal, and had the same issue in a 70’s V-12 that was there for some work. I know that cannot be the case as the first 10 years were fine. He tells me he cannot increase the pedal as there is a resulting rattle or scraping sound when the pedal is fully depressed. Thoughts?
Sounds like either too much free play in the slave and yoke link or still have some more air to bleed. Clutch is not fully disengaging. Does the initial feel of the pedal seem too easy? Have you heard the noise with additional clutch travel? If the throw out bearing is really riding up on the input shaft and making racket when fully forward that is not good. Something amiss with the clutch disk or pressure plate… Maybe get someone else to Rebleed and adjust before pulling another clutch replacement job.
He put the wrong friction bearing in…there are 3 for sure different (hight only) and maybe 4.
Maybe the master cylinder has the mount spacer (look where the 2 bolts mount the master cylinder to the bracket)…if so, you could remove the spacer and thus have more travel against the pressure plate…my bet is…you do not have the spacer…
You can do a search in the archives under my name…about 3 years ago…Peter and I covered the different friction bearings…I did a mock-up on the garage floor and caught the issue before
If it becomes a question of which TOB was used - you probably have a hole in the bell housing that lets you get a look at it:
The light spot is a dab of paint I use to take comparative photos thru the years to track wear.
So what he’s saying is that he’s installed a new clutch on more than one occasion and the clutch hasn’t worked so this is normal?
He’s incompetent. Find someone who isn’t.
You will wear out your synchromesh very, very quickly with the problem as you describe it.
I am not sure how much you have used your car since the clutch problem has come up, but you may already have dramatically shortened synchromesh life as the clutch is not fully disengaging.
It may be that you might want put new synchromesh rings in when transmission is pulled
i do not understand that there is a noise if the pedal is some how pressed further.
i think mechanic has done something wrong
Dennis 69 OTS
Here is a thread that begins with discussion of spring v diaphragm clutches but (at post 28) gets into the different throw-out bearings involved. Might help you check which you have:
Photo of each farther along in the thread.
I could not find the post you referenced. Not sure whether I have a spring or diaphragm plate. Trans has been replaced with an all synchro unit from a later car, does that make a difference? Odd thing is that it works fine when cold, but not when warm. The same as it did right after new clutch with original slave/master so I hesitate that it is a bleeding issue? I have not heard the noise the mechanic mentioned if the adjustment is too long…
Are there holes in the bottom of the bell housing?
One hole may have a little rotating metal cover, the other (closer to the gearbox) may be open.
It is that latter hole that gives you a peek at the clutch and also the throw-out bearing and will let you determine which you have.
If your car got the three-arm clutch unit, the arms may be in need of adjustment. Not a common issue, but happened to me. Take a look here:
I have both holes. Would an incorrect TOB work fine when cold but not when hot? Perhaps my mechanic cannot properly bleed a hydraulic clutch? I find that hard to believe as he works on many high end cars of this vintage here in Palm Springs. Always a treat to see what is in his shop…
What hydraulic fluid/oil are you using in your transmission? Try changing the transmission oil to see if that cures it. When the transmission is cold the oil is thicker, and when hot it is thinner. You might be going down the wrong rabbit hole. Not a heckuva lot changes with the clutch release bearing due to temperature change. If it works just fine when cold, then I’d start looking at things that change due purely to temperature, like oil viscosity.
Maybe I should be looking at air in the hydraulic system - air would expand when hot, increasing pressure on the clutch? I don’t know if my mechanic bled the clutch with a vacuum or another body on the pedal. My recollection is that while I can successfully bleed the brakes with another person on the pedal, I have had to use a vacuum bleeder on the clutch…
The photo I posted somewhere above shows what one might see thru the rearward hole – the throw-out bearing and the fingers of the diaphragm clutch. Is that what you see in yours?
I have always found the clutch pretty easy to bleed (certainly easier than the brakes) and if there is air it affects shifting whether hot or cold. One clue - if there is air in the system often rapid pumping of the pedal will briefly restore normal function as the air gets compresses for a short while.
Do you agree this is not a TOB issue since it is only an issue when hot? When cold the clutch behaves normally, stopping the gears from spinning to facilitate engaging reverse without any grinding, and beginning to move the car at about 1 1/2 inches off the firewall. When hot, forget putting into reverse without pushing on a synchro to slow things down then quickly cramming reverse. Car will begin to move within the first 1/2 inch release. If not a bleeding issue, what could it be? I might try to jack the car and bleed in the morning anyway…
I think that is a very good idea. You may even be able to do a gravity bleed… some do, though I find an active bleed more satisfying.
I have a vacuum bleeder so am good with that.
Well I am not certain whether bleeding the clutch again helped, or the cooler ambient temperature, or both. Not as bad as it was earlier, but still does not fully disengage the trans when warm. I am able to “pump it up” a bit which helps. However pumping it up also increases the travel enough that I can start to hear the “grinding” noise when fully depressed in neutral, which is like metal rubbing on metal. I reckon the fact that I can “pump it up” indicates there is still some air in there? However the “grinding” position of the clutch is very close to the “disengaged” position - is that a wrong TOB? Here are a couple pics, but they didn’t turn out too well as the car was only about a foot off the floor.
The wrong tob/pressure plate combination would be unlikely to work right hot or cold, so I think you’re doing the right thing chasing the hydraulic system. The fact that it behaves differently when you pump it up would confirm a problem, either a faulty seal or air in the system. I usually bleed mine by gravity, but if you have a helper the key is to open and close the bleed screw while the pedal is being pushed down, don’t wait to close it until the pedal is all the way down like you do with brakes. Otherwise the springs in the pp can draw air back into the system.
I suggest you ask someone on the forum to measure the distance the throwout bearing lever moves when they press their clutch pedal down to the floor. This is a two person job and I would do it but not possible at present on my car.
Then measure how much yours moves. This will pinpoint the problem. If yours moves the same distance as others, then your hydraulics are ok and the problem is in your clutch/diaphragm,throwout bearing assembly.
While we are at it helping out… how much is your clutch pedal free play? This is how far you can press the clutch pedal before you feel resistance that tells you the diaphragm is starting to be pushed. You can do this with your hand. It should be 1/2 inch to an inch maximum. There should be some free play or the graphite bearing will always be touching the diaphragm assembly and will wear out very quickly. If it is two or three inches, you have found the problem
Dennis 69 OTS