Clutch Issues

[e philpott]

Maybe listen to the Master and slave if you can with a Stethiscope and see if one of them makes a bunch a noise in the spot it acts up

[preaction]

I have a T56 with a Ram hydraulic bearing and twin disk RXT in my 68, it was very hard to get bled but once I got there it has been working great. I do remember having to have to change the trans snout to get it right.

[TomP]

I hate hydraulic clutches. So much so that I converted my Ranger to a cable.  They just don't give a positive feel.

[My427stang]

Jay, what does your setup use for a spring setup to return the TB to original position? Are they external to the throwout bearing, or does it just relax on it's own?  Is the master and throwout bearing a matched pair, or did you pick them?

I wonder if your design has some extra resistance and needs a little more spring pushing back through the master cylinder?

[scott foxwell]

If no one has mentioned it, make sure the TO bearing isn't binding on the extension.

[mbrunson427]

Just to make sure....there isn't any kind of fluid return regulator on the hydraulic line right? The car I drive to work every day is an Acura TL, I got it in the 6 speed manual, it has a hydraulic clutch. I was having issues with erratic clutch behavior. After looking online for a while I realized that they put a regulator in line to help pedal feel and not let bad drivers release the clutch too quickly. It's a common piece that people have problems with. I bought some Honda tuner guys kit that eliminates the fluid regulator.

Not sure if your setup has one...but this is my one experience. And the symptoms don't sound too much different than yours.

[Chrisss31]

In the interest of keeping things simple I'd just try to bleed it again.  It really sounds like there is some air in the system.

[TomP]

I suppose another thing to check is that the t/o bearing is the correct diameter for the clutch fingers and not running off the edge.

[ericwevans]

Any progress Jay?

[jayb]

OK, to answer some questions, the throwout bearing returns on its own, unless there is an internal spring that I don't know about.  The throwout bearing is solidly fixed to the transmission input shaft sleeve, and then expands towards the clutch fingers when the pedal is depressed.  The throwout bearing and master cylinder were bought from American Powertrain in the same kit, so they are designed to work together as far as I know.  The line from the master cylinder to the throwout bearing is direct, no check valves or anything in between, unless they are in the throwout bearing or master cylinder themselves. 

So, here's a new twist.  Sunday the wife and I took off for a car show about 50 miles away.  This involved some freeway driving for most of the trip, where I was going between 70 and 80 the whole way.  I had not yet put this kind of driving on the car, being mostly limited to around town driving and local roads up to 50 MPH.  Sunday, after getting off the freeway, suddenly the clutch worked perfectly!  No sticking at all.  It worked great all the way to the car show.  We didn't stay too long, only about 3 hours, and when we left the clutch still seemed to be fine.  Back at home I parked the car, and after thinking about this I suspected that the heat buildup on the freeway was the reason that the clutch started working properly.  Monday morning I got back in the car to run some errands, and sure enough, the sticking was back.  However, this time, after about a 15 minute drive around town, it started working perfectly again. 

It seems clear that there is some tolerance that is too tight somewhere, and heat buildup causes the parts to expand and start working normally.  The throwout bearing is the primary suspect, I think.  However, it may be that after some time it will wear in and the problem will disappear, because it seems to be improved after the trip on Sunday.  I will have to drive it a little more to see if it really is better now. If it doesn't get better after another 1000 miles or so, I think I will probably replace the throwout bearing.  What do you guys think, am I on the right track?

[Heo]

I think you are on the right track something is sticking. Probably
wear in after some use

[turbohunter]

Jay, I run into that very same thing with my brown truck. It has a McLeod single disk. When I'm in traffic and shifting a lot it starts to stick. Not stop like yours but I can feel it grab. I took it apart and champhered the front and rear edges of the throw out bearing made sure there was grease in the center depression and put it back together. It was better but not gone. I think you are on the right track also with heat expansion.

[My427stang]

I think it sounds as good as anything.  I'd put some more miles on it, and if you decide to pull it, then look for dry spots or potential misalignment/off center components

[turbohunter]

I think I feel your skepticism Ross.
Why would something made to work together like that succumb to heat expansion when that should be part of the formula? The only thing I can come up with is tight tolerances of new bearings used with older used sliders.
After I put mine back together and the problem was still there I figured I should have at least straight edged the slider.
Also thought about to much clearance and the bearing rocking but seems unlikely. Can't take anything for granted.

[machoneman]

I do remember a somewhat similar issue on a Chevy clutch job. IIRC, the fork-end was for a big diameter t-bearing while the actual t-bearing was a small one, at least the flanged part that intersects with the fork's fingers. Anyway, as one worked the clutch pedal (mech linkage here) the t-bearing seemed to drag 1/2 way down the stroke, then release.

But, not quite the same thing nor heat related as in Jay's case. If it clears up after more driving, saving a lotta' work (!) I'll bet Jay finds witness marks later, leaving a clear trail of what exactly it was.