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Troubleshooting a clutch issue (sticking to the floor)

Posted: Wed May 20, 2015 3:41 am
by Fkyx
Alright. So I've searched for issues much like mine, but haven't yet found an answer that quite fits what's going on with my 1991 SS.

The car has been sitting (not running) for about 5 years now. A few months ago, I noticed that the clutch pedal snaps down to the floor after about 25% of its throw, and doesn't return on its own.

The first few pieces of advice I found related to this issue have to do with bleeding the clutch. I bled it from the slave cylinder, using the method my Chilton's manual describes with no noticeable luck. I followed a slight variation of this method that I found in someone else's post, also with no noticeable luck. I tried a bunch of my own variations of this, also. No luck.

After feeling a little defeated, I noticed that if move the clutch pedal back and forth, from the floor to about 3 inches away from the floor, by hand, I do get some of the feeling back, and it will stay off the floor. But if I pull the pedal all the way back out, then push it back in, it snaps right back to the floor.

I can push the pedal off of the floor by pressing the clutch fork back from the engine bay, if that makes any difference, but once the pedal is all the way out, it exhibits the same snap to the floor issue.

After doing the pumping thing, the clutch seems to operate properly (car will roll while in gear when depressed, will hold its position when not depressed), but possibly not fully. However, the throw on the pedal is really short.

The clutch worked just fine before the car began its slumber, and the slave cylinder does not appear to be leaking at all on its own.

Any ideas?

Thanks.

Re: Troubleshooting a clutch issue (sticking to the floor)

Posted: Wed May 20, 2015 6:12 am
by PhyrraM
If it is pushing back when you manually manipulate the clutch fork, it sounds like there is a problem with the clutch itself.

A hydraulic clutch is self adjusting, so as long as your confident there is no air in the system, and there is no indication that the master or slave cylinders are bad/leaking (usually a bypassing cylinder will leak where the 'rod' exits) then it must be the clutch itself.

I suppose a long-shot is the length of the push-rods (either the pedal-to-master or the slave-to-fork) could be wrong/not stock.

Re: Troubleshooting a clutch issue (sticking to the floor)

Posted: Wed May 20, 2015 6:12 pm
by Legacy777
My brother has a Mazda 323 GTX that has been sitting for a long time that we tried to get going again when I was up in Seattle over Thanksgiving. It exhibited very similar symptoms with the clutch and I'm pretty sure the seals on either the slave or master cylinder are shot. Since it's been sitting in the garage so long I don't think he ever got around to replacing the slave & master cylinders.

The other thing to note is that there is a clutch damper that can be found on the side of the transmission. When you bled the clutch, did you bleed air from the damper as well? Even if you didn't, the chances are still pretty good either the slave or master clutch cylinder seals are bad.

Re: Troubleshooting a clutch issue (sticking to the floor)

Posted: Wed May 20, 2015 7:27 pm
by mike-tracy
Don't go with a parts store one on these. I got 3 bad ones in a row. They all leaked out of the master cyl seal. Between lost wages from not being able to get to work to stress and frustration, I would have been able to purchase several oem ones. Fourth parts store one (which was an oem one that was rebuilt iirc) worked.

Re: Troubleshooting a clutch issue (sticking to the floor)

Posted: Wed May 20, 2015 8:09 pm
by jamal
Pulling the MC and doing a bench bleed might take care of it. You basically just stick it in a vice or something so it doesn't move, and run a piece of tubing into the reservoir from the port, then cycle the piston a bunch of times. Then keep the port plugged as well as you can until it's reattached to the line, then bleed the slave again.

Or if you just go get another MC that's the bleed procedure you'll need to follow. I've had good luck with centric MCs, you want part number 136.47000 I think.

Re: Troubleshooting a clutch issue (sticking to the floor)

Posted: Sat May 23, 2015 6:09 pm
by Fkyx
PhyrraM wrote:I suppose a long-shot is the length of the push-rods (either the pedal-to-master or the slave-to-fork) could be wrong/not stock.
So the previous owner swapped it from 4EAT to 5MT, but I cannot recall which car the transmission came from. I do know that the clutch operated fine before and after (though for only a short drive) the EJ20G swap. Everything seems to be operating (mechanically) from the inside of the car, but I don't know how I would know for sure if the push-rod length on the slave is proper, aside from the fact that everything was fine before this long downtime.
Legacy777 wrote:The other thing to note is that there is a clutch damper that can be found on the side of the transmission. When you bled the clutch, did you bleed air from the damper as well? Even if you didn't, the chances are still pretty good either the slave or master clutch cylinder seals are bad.
I didn't bleed the clutch damper, actually. I didn't bother to see if it's even still there, to be honest. Haha. Is it possible that the seals could cause this issue? Or is this just a heads-up saying my seals are probably bad from sitting for so long?
mike-tracy wrote:Don't go with a parts store one on these. I got 3 bad ones in a row. They all leaked out of the master cyl seal. Between lost wages from not being able to get to work to stress and frustration, I would have been able to purchase several oem ones. Fourth parts store one (which was an oem one that was rebuilt iirc) worked.
Noted. On this note, I imagine I could use a master/slave out of another car in Subarus lineup. What are my options, if I were to take a crack at finding one in the wrecking yard?
jamal wrote:Or if you just go get another MC that's the bleed procedure you'll need to follow. I've had good luck with centric MCs, you want part number 136.47000 I think.
Thanks. I'll try some other things and keep this in mind, failing those other things.


Thanks a ton for your input, guys. I'll be attacking it again this Monday, so if anyone else wants to chime in with ideas, please feel free!

Re: Troubleshooting a clutch issue (sticking to the floor)

Posted: Sat May 23, 2015 11:50 pm
by Tommio RS
So

This may or may not help but i will share anyways.

I have had a sorta clutch related issue like this before.

The clutch would feel totally fine until you drive it around for 1hr or so.

Then your clutch sinks and you loose the clutch......


I have done this job 2 times in my job and the only thing i could find to fix the issue was.


Remove the entire clutch hydro master,flex line,slave FROM the car.


Replace:

clutch master
slave cylinder
flex line

Bleed entire system OFF the car with some tricks and such.

Worked like a charm


Most expensive part is the clutch master.

I would personally just risk getting a good used one.
The flex line and slave OEM should not cost more than $100

The cars i have done this on are:

2003 forester NA
2002 outback NA

It was SOO bad on the 2002 outback i did, before coming to me he replaced the clutch due to slippage!


Note:

I think it has to do with the clutch master or the flex line.


Hope it helps some what!