weird clutch problem

Synchros shot? Weird noises while shifting? Not sure what needs to be replaced?
watkins
Master Standardshifter
Posts: 15880
Joined: Sun Jul 01, 2007 12:42 am
Cars: '08 Saab 9-5 Aero wagon
Location: Salem, MA

Re: weird clutch problem

Post by watkins »

Bleed it. May be bubbles in the line. Even if this doesnt solve a damn thing, its no time wasted
permabanned
Master Standardshifter
Posts: 2472
Joined: Sun Sep 21, 2008 1:48 am

Re: weird clutch problem

Post by permabanned »

94Corolla5Speed wrote:Your slave is $45 :lol: Mine's $20, no joke :lol:
race car parts, race car prices.

in all reality, i can drive without a clutch for a day or 2, then ill go to a junkyard and get a genuine OEM mazda slave cylinder for a few bucks. they are much better than the cheap chinese shit they sell at parts stores.

but then again, im sure ill have the F23 in by then, so i wont need the mazda OEM slave cylinder, i wont have a slave cylinder at all. hydraulic throwout bearing FTW
95 probe GT
02 yamaha R6
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gamer10101
Junior Standardshifter
Posts: 5
Joined: Thu Mar 05, 2009 10:32 am

Re: weird clutch problem

Post by gamer10101 »

I've noticed that it doesn't happen unless I have been driving for at least 15-20 minutes. But even then, it might not happen at all. It is the complete randomness of when it happens that is driving me nuts.
Tinton
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Cars: 91 MR2t, 88&86 Fieros
Location: GA

Re: weird clutch problem

Post by Tinton »

It sounds like your clutch hydraulics are still keeping the clutch slightly disengaged when you release the pedal, so it slips. It only happens after the car is warm though, which is weird. I think all hydraulic clutches automatically adjust, can someone correct me on this? If they don't all automatically adjust then you probably have some mechanism that keeps the clutch engagement point consistent. This could be malfunctioning and bringing the engagement point too high up in the clutch travel when the car gets hot. Does the engagement point change in the pedal though?

Going into more serious things, you could have something stuck in the clutch mechanism. With my '88 Fiero, I had to get a new clutch put in a couple months after I bought it because a spring popped out of the pressure plate and would lodge itself between the pressure plate and clutch or something. You could have a similar problem where something gets between the clutch and flywheel, allowing a bit of clutch slippage when its engaged.

Its very hard to tell without knowing the car, and more importantly, without seeing the car and troubleshooting it directly. You should go get it checked out, because it could be a number of things causing the problem. Just make sure to get a 2nd opinion if it comes out to being a really expensive fix. I had a mechanic once who wanted to change my clutch in my '86 Fiero because the car wouldn't shift, it turned out to be a loose shift cable. What would've cost like $800 ended up costing....nothing.

Edit: it could also be a defective master or slave cylinder. When you push the clutch pedal, the pistons inside the cylinders move forward through the bore due to hydraulic pressure. When you release the pedal, the pistons inside the master and slave cylinders are supposed to move back. They could be getting stuck somehow when the car's hot, that could cause the problem you're having. Pumping the clutch pedal would also likely fix the issue temporarily, like what you're experiencing.
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Rope-Pusher
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Cars: '08 Jeep Liberty
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Re: weird clutch problem

Post by Rope-Pusher »

When the slipping occurs, try sliding the toe of your shoe (with your foot in it) under the clutch pedal pad and gently pulling it up/back. Does this eliminate the slipping? If so, clutch pedal assembly or Master Cylinder may be binding.

Apply the handbrake, chock all four wheels in both directions, put the trans in Neutral. Have someone get in and slowly pump the clutch pedal up & down while you slide under the front of the car with a flashlight (opening the hood lets some light shine down there, too). Watch how the slave cylinder rod extends and retracts. It should move smoothly. Is it corroded? Does it exhibit stick-slip motion? Ifso fatso, apply some lubriplate to the rod, where it contacts the release lever (should be a plastic cap over the end of the rod) and where it moves into the bore of the slave cylinder.

As designed, the release system DOES "adjust" itself every time the master cylinder returns to the unpressured position (piston fully retracts, uncovering the port to the fluid reservoir, so extra fluid can vent or fluid from reservoir can refill the lines.) If the hydraulics aren't releasing when the foot comes up off the pedal, it is most likely that it would be something wrong with the slave cylinder, but it is much easier to check to see if the clutch pedal is restricting the master cylinder piston from reaching the vented position.

If this car has been driven hard (side-stepping or dumping the pedal while the throttle is being tickled aggressively), it may be possible that the clutch hub is damaged. Maybe the damper springs are slipping out of place from time to time (after high rpm?) and getting in the way of the clamping between the pressure plate, clutch disk and the flywheel.

Hominy miles on the clutch? Might it be glazed from heat build-up due to excess slipping?
'08 Jeep Liberty 6-Speed MT - "Last of the Mohicans"
gamer10101
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Joined: Thu Mar 05, 2009 10:32 am

Re: weird clutch problem

Post by gamer10101 »

well after some testing, I may be blessed as well as cursed, I tried to pull the clutch pedal up when it was slipping and it seemed to have worked but I only tried it once, reason being it hasn't happened since. I'm guessing maybe there was too much pressure in the tubes and for some reason the clutch wasn't comming back up enough to uncover the hole to the reservoir. I notice that the pedal does have a little play, about 1/4 to 1/2 inch where there is no resistance when you release the clutch, meaning after a shift, you can push the pedal in a 14 inch or so and it will bounce back fine but no resistance. But if I pull the pedal up, it does come up ever so slightly, not even 1/4 inch, but for the next press there is a very slight resistance for that first 1/4 inch. Even if I push it in that 1/4 inch then let it come back, the resistance is gone. the resistance change is so small that my brother says he can't even feel it but I'm sure it's there. Either way, it's gone so I'm happy. Now to troubleshoot my next problem since I changed/rotated my tires, I have a nice low hum from 50km/h to 110km/h, seems like it comes from the rear. But at least I have one problem solved. Thanks for the help guys.
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