Clutch pedal sticks to the floor after flush.

[Rick Lee]

Can't believe this happened to me. I've done this job so many times and was stupid enough this time to button it all up, pour out remaining ATE fluid and THEN check the pedal. Stuck to the floor.

I used a Motive on the fluid reservoir and a vacuum on the bleeders. At some point, I decided to push the clutch pedal down, just to move whatever was left in the MC. It didn't come back up, but I figured it would once I ran new fluid through it. Silly me. I had all the old blue fluid come out until the gold fluid ran clear in the tubing.

How to fix this? Do it the old fashioned way with Mrs. Lee holding the pedal down while I burp the bleeder? Use the Motive with only air in it to put pressure on the line? Put some more fluid in there? Do I need to pull the pedal up at some point?

[Fairfax 944]

Can't believe this happened to me. I've done this job so many times and was stupid enough this time to button it all up, pour out remaining ATE fluid and THEN check the pedal. Stuck to the floor.

I used a Motive on the fluid reservoir and a vacuum on the bleeders. At some point, I decided to push the clutch pedal down, just to move whatever was left in the MC. It didn't come back up, but I figured it would once I ran new fluid through it. Silly me. I had all the old blue fluid come out until the gold fluid ran clear in the tubing.

How to fix this? Do it the old fashioned way with Mrs. Lee holding the pedal down while I burp the bleeder? Use the Motive with only air in it to put pressure on the line? Put some more fluid in there? Do I need to pull the pedal up at some point?

If you have no air in the system, and the clutch slave has not failed, you might be able to just pull the pedal up and all will be good. Give it a try.

[HoodPin]

Don't know how the system compares to a 944's, but had similar problem last year that turned out to be a leaking clutch fluid line. In the 944, the clutch's pressure plate pushing back provides fluid pressure back up the line to help push the clutch pedal back up. When the pedal was pushed down, some fluid would squirt out of the leak relieving the pressure and the pedal would stay down. Was not fun fishing for the pedal with the toe of my foot....during a race. :(

[BillC]

You've probably solved this by now, but here's what I would recommend:

Close the bleeder on the clutch slave cylinder and then pull the clutch pedal back up by hand.

There's an over-center spring that helps counteract the force from the pressure plate. If you push the clutch pedal down with the bleeder open, there won't be any force from the pressure plate to counter and the over-center spring will pull the pedal down to the floor and hold it there.

If you make sure the reservoir is full when you pull up the clutch pedal, you probably won't even need to re-bleed it. Just top off the reservoir afterward, since the level will drop.

[Rick Lee]

Haven't gotten to this yet, went to San Diego for the weekend and then flushed Mrs. Lee's E92 brakes today. Will do this tomorrow night. Thanks.

[Eric S]

Sounds like you ran the brake fluid reservoir too low when you bled the slave/pressed the clutch. I had that happen once and it took a panic call to ViceGrip to help me figure it out. I was being very careful to not get to the low level indicator, but a 964 (and likely others) there is a level indicator "PP" that is where the clutch stops pulling fluid and starts sucking air, and for obvious reasons it is way higher than the brake low level indicator; once you go past that point when bleeding the slave and press the pedal it will snap to the floor and won't come back up. I had to pull the pedal back up and re-bleed the slave and it was fine. Bleed it, then bleed it some more. And to be safe, probably a good idea to re-bleed the brake lines too.

[Rick Lee]

I don't think that's what happened, as I was using a Motive and there was a lot of fluid still in it when I was done. I did have that happen once when the Motive tipped over and the pick up hose inside started sucking air. But that didn't happen this time.

[Eric S]

I don't think that's what happened, as I was using a Motive and there was a lot of fluid still in it when I was done. I did have that happen once when the Motive tipped over and the pick up hose inside started sucking air. But that didn't happen this time.

Sorry it didn't help. Sounds like you'll need to consult one of the more knowledgeable resources on here. Of course, they might be more expensive! ;-)

[ausgeflippt951]

Have you had a chance to fiddle with it yet?

Pull the clutch pedal back up; does it immediately go straight to the floor again?

Are you sure there is actually fluid in the reservoir? These ATE reservoirs have a baffle between the clutch side and the brake side; the clutch side can be too low despite there being fluid in the brake side.

Are you sure the lines are tight? Does your car use the cloth-covered rubber line going from the reservoir to the master cylinder? This is a very common failure point: either they are not tightened tightly enough or they wear out and invariably let small amounts of air in.

Are you positive the master and slave are in good, working order?


If everything listed above is fine, then re-bleed. You still have air in there.

[RunningonMT]

Collin is absolutely correct on this! AND there's only about 1/2" difference in a full reservoir and the level where there's no fluid going to the clutch. Please don't ask how I know! I may have some photos on the computer at home. If so, will send later.

[Vicegrip]

It is not a matter of how much fluid is in the Motive to matters how much air is in the brake reservoir. Even when you are replacing the fluid as it is being drawn out if the fluid is below the clutch tube the clutch will take in air. As said the clutch takes fluid from well above the bottom.

[Rick Lee]

As I've done this plenty of times and never had the pedal stick to the floor, I'm thinking I just didn't have the bleeder closed all the way when I went to pull the pedal back up, and so it sucked in some air. If I introduced air at the fluid reservoir, it seems to me I'll have to do a lot of pumping to get it back out of the bleeder. I plan to attack this tonight, as I need the car tomorrow.

How should I do this? Use Motive or old fashioned way with assistant working the pedal while I work the bleeder valve?

[RunningonMT]

So here's the picture of my brake / clutch reservoir I mentioned in an earlier reply. The physical difference in level at maximum and the level at minimum is 1.3" (arrows pointed to the left). The level at which the clutch quits working is 3/4" below the maximum level (arrow pointed to the right). Clever German engineers! Stopping is more important then shifting.

Personally, I would use the Motive, but fill it with a goodly amount of brake fluid. First, pressure the system with the filled Motive, then pull up the clutch pedal, then bleed the clutch system. Would also frequently check the actual level in the reservoir to assure it stays within the safe clutch zone described above.

[Vicegrip]

again you don't need a lot in the Motive you need a lot in the reservoir.

If by chance you did get air in the clutch system it can be hard to bleed out. Air tends to get trapped in the slave cylinder. Many quarts of fluid passed through using the standard format flush will not get the trapped air. One method that tends to work on most setups and does not require jacking the car front or back in the air is the froth and bleed method.

Flush the system using the normal method and test the clutch. If the pedal is still soft get a helper. While you are under the car ready to let fluid out have the helper pump the clutch vigorously about 20 strokes as fast as they can. As soon as they stop open the bleed screw and let the now frothed up and a bit ticked off and dizzy fluid out until it flows clear. Repeat until the pedal firms up and you get clear bubble free fluid after a pump and dump.

[Rick Lee]

UPDATE

This is weird. Just went to move the car into the big garage to do this job. I unscrewed the lid on the res. first and then pulled the pedal up by hand. Now it feels like a new clutch and stays up. WTF? Before I move cars around again and close it all up for the night, what caused this? I have a job interview on Thurs. and I can't ride my motorcycle there. The 993 is my only car. I need this to be working and reliable.

Yes, I am positive the MC and SC are fine. Never had a problem with either and SC was replaced last time the engine was out. In fact, IIRC, Ivan Arzola and Jack at Euro Pros personally flushed it upon install, but I have done so a few times since then. Never had a problem before this one.

[Noah]

The pickup tube in the fluid reservoir for the clutch circuit is placed higher than for the brake circuit. Very common with 993's to introduce air into the clutch circuit while bleeding brakes -- did it myself a few weeks ago. Just fill the reservoir up to the top, put the motive on it, and crack the slave bleeder, but start and stop bleeding at shorter intervals to fill up the reservoir.

[ausgeflippt951]

If all seems to be working now, I would recommend driving it extensively today as a shakedown.

Clutch hydraulics -- particularly on Porsches -- can be finicky. Sometimes the pedal will go straight to the floor for no reason and never do it again. If you're extra worried, you can bleed it one more time tonight after taking her out for a long test drive.


In addition to instilling confidence (or confirming you need to re-bleed), taking the car out for a shakedown will also help move around the fluid -- as well as any air bubbles that may be trapped in the circuit.



Good luck with your interview. You'll probably be fine. May want to swap cars with Mrs. Lee and have her be the one with a broken down 993 if things go south.

[Rick Lee]

I drove for just a few miles last night and it felt like new. Went to run errands today and pedal went to the floor again. I pulled it up and was able to pump it and drive. Still feels bad, but not as bad or as good as it was, still driveable. Might try another bleed tonight. But as long as it's driveable, I might just try to get through tomorrow and deal with it later. Job is in severe jeaopardy, so I need to take this interview tomorrow very seriously.

[ausgeflippt951]

Hope it went OK today!

[Vicegrip]

I drove for just a few miles last night and it felt like new. Went to run errands today and pedal went to the floor again. I pulled it up and was able to pump it and drive. Still feels bad, but not as bad or as good as it was, still driveable. Might try another bleed tonight. But as long as it's driveable, I might just try to get through tomorrow and deal with it later. Job is in severe jeaopardy, so I need to take this interview tomorrow very seriously. i had a clutch that did the same thing. the slave side seal was worn and sometimes rather than baloon up and seal it would simply let the fluid past the piston. Pedal flops to floor, foot flicks it back up and stabs into a push to force the seal to "seal"
I might be inclined to check the throwout and rebuild both slave and master if other stuff checks out. This assumes the pedal pivot is not stiff.

[Rick Lee]

And the mystery continues. I was rushing to get out of the house today, wearing a suit and it was damn hot out. Got in the car and pedal went to the floor. There was still some resistance and I was able to drive, but had to really push the pedal to the floor before shifting. I got used to it, was shifting slowly and then about a mile away from my interview, pedal returned to normal. I mean totally normal. It was like that for the rest of the day. I can't believe my MC or SC are bad, as this only happened when bleeding last week and both were perfect before that. T/O bearing was replaced with RS clutch and LWF in 2005 and 40k miles ago.

[Noah]

There's air in the system. Bleed it.