djohnston

Hi folks, this is about, once again, my '97 Integra GS-R.

The symptoms are these:

First drive of the day the clutch behaves perfectly normally.

After leaving the car parked for a short while (half hour or so), when I get in again and push the clutch pedal all the way down (stick shift in first gear) and then start the engine, I can feel the clutch "dragging" as if it's not fully disengaged from the engine and the car tries to creep forward. At this point, if I let the clutch pedal half-way up, all is fine, but if the pedal is all the way down, I can feel the clutch is partially engaging the engine, and further, I can't shift into any gear from neutral unless I let the clutch pedal half-way up. So I have to keep myself from pushing down all the way on the clutch in order to shift gears, but once I've driven a short while, the problem goes away!

The car has been in the shop TWICE now for this problem, they've given me two brand-new clutch master cylinders, bled the clutch fluid twice, and replaced the clutch, and still the problem occurs.

Hoping someone can diagnose what appears to be a hydraulic issue better than the dealership, who obviously doesn't know how to fix it, and because the problem is intermittent it naturally doesn't do it for them.

cdelena

Sounds like it might be the slave cylinder rather than the clutch master cylinder.

The Reverend

Or even a pressure plate/shift fork/release bearing mechanical failure.

cmnsnse

Yeah and its even easy enough for them to peek in there to check.

djohnston

cmnsnse, was that sarcasm? Sorry if I'm not getting it. I'm only asking because it was explained to me by the Acura tech that such repairs involve a complete tear-down of the transmission and about 5 hours of labor.

cmnsnse

Nah, really if its related to the clutch release fork, there is a boot you can pull aside and/or remove the slave cylinder to check operation or free movement.

If your clutch is going from engaged to slightly dragging, then that suggests a seal in the system(Hydraulic)

In my experience the slave cylinders go first and then the master cylinders, I dont see that you said anything about the slave cyl.

Now to discern between hydraulic failure and mechanical, does it fail all the time when the pedal is on the floor? Mechanical should be repeatable. Does the problem go away if you pump the clutch pedal? pump it a few times and then press to the floor? You say the clutch has been replaced, that means mechanically it should be sound.

djohnston

cmnsnse-

Here is some further diagnostic (hopefully) information.

The problem never happens on the first drive of the day when the car is cold, and in fact only occurs after the car has been driven, fully warmed up, then allowed to sit (engine off) for 15 minutes or so. But, if the car is allowed to sit for a few hours and fully cool off, the problem disappears again until the car has warmed up.

Is it possible, if the clutch hadn't been bled properly, that an air bubble works it's way into the slave cylinder only when the car is warm because the clutch fluid is less viscous then?

I've also been told by another person that slave cylinders are notoriously difficult to bleed, any thoughts (from anybody) on this? The car goes back under the knife tomorrow for the third attempt to remedy this problem.

To reiterate, pumping clutch pedal does not help, clutch pedal feels "stiff" when problem is happening, and problem only happens after car has been driven and warmed up.

Help!

cmnsnse

geesh, now Im thinking throwout bearing carrier, that part never gets changed, prolly the bearing too.

Hmm lemme think for a few on that.

cmnsnse

OK its got to be this, and please tell me its a push type diaphram on the pressure plate, the throw out bearing or carrier must be a bit past where it should be, and so your going past disengagement and actually pressing the fingers of the clutch into the disc.

The simple fix would be to change your pedal height, lower to reduce travel. Adjust both the stop screw and the pushrod that acuates the master cylinder.

It must be just perfectly screwed up for the heat to bother it, but not before or after.

djohnston

Just had the Integra in for it's third attempt at fixing the intermittent clutch problem, and cdelena wins the prize for guessing the cause first, but my hat is off to The reverend and cmnsnse as well for their diagnostic expertise.

Today they swapped out the clutch slave cylinder with a new one, and hallelujah, the problem seems to be fixed. What irks me is that they didn't even bother to check the action on the original slave cylinder, as cmnsnse suggested, they just took off the old and put on the new, but this seems to have been the solution.

And this repair was not based on any intuition on their part, because I asked the tech if he had any ideas about what was causing the problem, and he said he'd never seen this before. Hardly inspires confidence in this shop.

Thanks again gentlemen for all your help, it made me sound like I knew what I was talking about when discussing it with the dealership, for which I am eternally grateful.