Clutch pedal will not depress

[mattg1.8]

Just did a motor swap and got everything back into the car today. Bolted the slave up and went to test it and the pedal was rock solid. I figured the rod was not aligned correctly so I popped it off and tried to press the pedal to make sure that was the issue and it still would not depress. Didn’t have any issues with the clutch before the swap, is this a symptom of a bad slave? Thanks.

[JustManson]

So the pedal is stuck in the top position?

And cannot be depressed at all...

I’m thinking the master might be stuck....

Can you push the rod in and out on the Slave?


Sent from my iPhone using Audizine

[mattg1.8]

Yes it is stuck in the top position and yes I can depress the slave with the rod pretty smoothly. Where’s the master located?

[JustManson]

The master is inside the cabin.

Pull the kick panel off under the dash where your clutch, brake, and gas pedal is.

The master connects to the clutch pedal itself. Looks like a black plastic pump. I’ve read of the master (I just changed mine) getting stuck internally before popping. It’s the only part that would keep the pedal from moving inside the cabin.






Sent from my iPhone using Audizine

[mattg1.8]

Got around to looking at it today. Popped the slave off again and tried one more time. Pedal was still solid. Then I opened the bleeder on the slave and pressed the pedal and it went to the floor like normal but stayed down there on its own. Closed the bleeder, pulled the pedal back up to the top and tried to push again and it was again too solid to move. I then pulled the hydraulic feed line to the slave off and pressed the pedal and it shot fluid out through the feed line and the pedal depressed normal. It sounds to me like the master is working correctly and theres something blocking the slave from operating correctly. Anyone have any thoughts on this? My diagnosis is faulty slave.

[slowSfaux]

Clutch installed incorrectly, or the wrong tob/pp combo.

[mattg1.8]

Clutch installed incorrectly, or the wrong tob/pp combo.

It’s happening with the slave cylinder removed though so the clutch should be out of the equation. It’s the same clutch setup I had before so it can’t be the wrong setup but in what way could it be installed incorrectly? If the tranny shaft lined up with the disc you would assume it’s good to go right?

[slowSfaux]

Oh I must have misread, I didn't see you say that the pedal was still rocksolid with the slave removed from the transmission but with the slave line still connected. If that's the case, then yes, the symptoms point 100% to a faulty slave.

[Trb1]

It should be rock solid with the slave removed because there’s no pressure plate to depress the slave cylinder back into it’s closed position. If you push the slave rod back in and hold it, I guarantee the clutch pedal will depress again. If you try and force it, you’ll blow the seals on either your slave or master.

[mattg1.8]

It should be rock solid with the slave removed because there’s no pressure plate to depress the slave cylinder back into it’s closed position. If you push the slave rod back in and hold it, I guarantee the clutch pedal will depress again. If you try and force it, you’ll blow the seals on either your slave or master.

So that would suggest there’s something wrong with the clutch. The clutch seems too straight forward for their to be an issue with though. I bolted the flywheel up and put the disc in and the pressure plate on. The tranny slid on and I verified the splines we’re engaged when I wasn’t able to turn the driveshaft hub by hand any more. The tranny bolted up and I assume all is fine. Am I missing something in there??

[slowSfaux]

It should be rock solid with the slave removed because there’s no pressure plate to depress the slave cylinder back into it’s closed position. If you push the slave rod back in and hold it, I guarantee the clutch pedal will depress again. If you try and force it, you’ll blow the seals on either your slave or master.

Not true, you should spit the rod right out of the slave. It's happened to many people who don't line up the rod with the release fork.

What it sounds like is fluid isn't acting on the rod within the slave. It doesn't take much pressure to shoot that rod out, definitely not enough that anyone would call it "rock hard".

[Trb1]

Not true, you should spit the rod right out of the slave. It's happened to many people who don't line up the rod with the release fork.

What it sounds like is fluid isn't acting on the rod within the slave. It doesn't take much pressure to shoot that rod out, definitely not enough that anyone would call it "rock hard".

Oh it’s definitely true. If the Slave is fully extended, rod in place or not, the pedal will be rock hard. If you install the wrong TOB (which I’ve seen done) and the clutch fork doesn’t retract, the seals will blow out if you press hard enough. I’ve watched it happen. Think about how a hydraulic system works.

[Trb1]

So that would suggest there’s something wrong with the clutch. The clutch seems too straight forward for their to be an issue with though. I bolted the flywheel up and put the disc in and the pressure plate on. The tranny slid on and I verified the splines we’re engaged when I wasn’t able to turn the driveshaft hub by hand any more. The tranny bolted up and I assume all is fine. Am I missing something in there??

Did you install an aftermarket clutch and not replace the throw out bearing? Different pressure plates use a differently stepped throw out bearing.

[mattg1.8]

Did you install an aftermarket clutch and not replace the throw out bearing? Different pressure plates use a differently stepped throw out bearing.

I used the same exact clutch setup off the old engine. The clutch has been installed for thousands of miles with no issues I just unbolted it off one engine and bolted it right onto the other one.

[ReggieNoble]

If the pedal is still hard with the slave off the transmission, I would look at the clutch master cylinder like stated in an earlier post

Sent from my LM-Q710(FGN) using Audizine mobile app

[wbrunner23]

You removed the plug from the port on the slave before installing the line, right?

[mattg1.8]

You removed the plug from the port on the slave before installing the line, right?

I haven’t installed a new slave yet, going to pick it up tomorrow.

[mattg1.8]

I’m not able to work on it today but tomorrow I’m going to attempt to stick a tool in the hole where the slave goes and try to manually disengage the clutch. If I am able to do that without too much force then I’ll assume everything in the bell housing is working as it’s supposed to. If not then I’ll probably have to yank the tranny again.

[mattg1.8]

I’m totally stumped. Did a couple things today.
-put the car in gear and turned the engine over by hand to ensure the output shaft on the tranny was spinning and it was
-put pressure on the old slave with it removed and the pedal worked normal
-I replaced the slave anyway
-I felt inside the slave hole and was able to pull the fork forward a little bit then push it back towards the front of the engine. I believe it’s supposed to have this small amount of play if it’s correct?
With the new slave installed it’s doing the same thing. I wasn’t able to fully bleed it by myself but it’s already getting solid about halfway down.
Am I installing the slave incorrectly or is there something messed up internally in the bell housing?

[slowSfaux]

And this is a 2.7? I only ask because this is the b5 s4 page, but you have 1.8 in your name, haha. The release fork is held in place by the little plastic holder with the bolted on metal clip at the bottom, and the tob in the middle. If both of those are in place, and the tob fits snugly around the input shaft sleeve, there shouldn't be much side to side movement of the fork.

Edit: I misread again, my apologies, I thought I read side to side movement. A small amount of in and out movement of the release fork is normal.

By chance did you forget to install the bellhousing spacer?

[mattg1.8]

And this is a 2.7? I only ask because this is the b5 s4 page, but you have 1.8 in your name, haha. The release fork is held in place by the little plastic holder with the bolted on metal clip at the bottom, and the tob in the middle. If both of those are in place, and the tob fits snugly around the input shaft sleeve, there shouldn't be much side to side movement of the fork.

By chance did you forget to install the bellhousing spacer?

Lol yes it’s a 2.7 when I made my audizine account I had a 1.8. The bell housing spacer is installed. I have an aftermarket (vast I believe) clutch. Idk if there’s a special way it needs to be installed?? But again, if the tranny went on I don’t see how it could be installed incorrectly.

[slowSfaux]

Does vast use a sachs or luk pressure plate? If luk, did you reset the self adjusting clutch before you bolted it back to the flywheel?

[ZAB5S4]

Had the exact same happen to me once after reinstalling the engine. The problem is with the release fork being misaligned or something else which is locking it in place. I had to remove the engine, correct the fork, and reinstall. Clutch worked fine after that.

[mattg1.8]

Does vast use a sachs or luk pressure plate? If luk, did you reset the self adjusting clutch before you bolted it back to the flywheel?

I have no idea what plate it uses. And I also have no idea how to reset it so hopefully not.

[mattg1.8]

Had the exact same happen to me once after reinstalling the engine. The problem is with the release fork being misaligned or something else which is locking it in place. I had to remove the engine, correct the fork, and reinstall. Clutch worked fine after that.

Dam. Was it obvious what was misaligned in there? Is there a way to test that it’s going to work once the tranny is bolted back up but before putting it in the car aside from making the slave the first piece to be hooked up and tested on install?

[Nollywood]

If you can depress the clutch pedal with the slave unbolted from the transmission, the bleed nipple removed or pressure line disconnected, then the master cylinder is not binding.

What could cause binding once it’s all back together, are the following:

1) Throw out-bearing sleeve damage, not allowing the bearing to slide along its length.
2) Incorrectly fitted throw-out bearing (slipped sideways) causing the bearing to bind on the edge of the sleeve.
3) Incorrect throw-out bearing (too tall) for the clutch and flywheel combined stack height.
4) Transmission spacer missing from between transmission and engine.
5) Damaged release fork (bent).
6) Damaged input shaft splines.
7) Damaged friction disc splines.


I saw a suggestion that questioned whether you adjusted / reset the self adjusting pressure plate before putting it all back together. This will not cause a locked pedal. The car will drive the same, service life however will be shorter; it will wear faster, especially if the engine is not stock output-wise.

Since the thread starter says the transmission spacer was installed, we can rule out #4 scenario. Personally, I’m leaning towards throw-out bearing issues (#1&2). Unfortunately, these will require pulling the transmission to rectify. You can try selecting first with the engine not running, making sure the front of the car is clear of obstacles. Then start the car in first, drive forwards, then cut the ignition. Try the pedal once more.

This sometimes works, and knocks the release bearing back into place, if it was misaligned on the release sleeve. You could be lucky.

Did you grease the input shaft serrations, and the throw-out bearing sleeve? Did you ensure the friction disc slides freely along the shaft, before it all went back together?

[mattg1.8]

If you can depress the clutch pedal with the slave unbolted from the transmission, the bleed nipple removed or pressure line disconnected, then the master cylinder is not binding.

What could cause binding once it’s all back together, are the following:

1) Throw out-bearing sleeve damage, not allowing the bearing to slide along its length.
2) Incorrectly fitted throw-out bearing (slipped sideways) causing the bearing to bind on the edge of the sleeve.
3) Incorrect throw-out bearing (too tall) for the clutch and flywheel combined stack height.
4) Transmission spacer missing from between transmission and engine.
5) Damaged release fork (bent).
6) Damaged input shaft splines.
7) Damaged friction disc splines.


I saw a suggestion that would questioned whether you adjusted / reset the self adjusting pressure plate before putting it all back together. This will not cause a locked pedal. The car will drive the same, service life however will be shorter; it will wear faster, especially if the engine is not stock output-wise.

Since the thread starter says the transmission spacer was installed, we can rule out #4 scenario. Personally, I’m leaning towards throw-out bearing issues (#1&2). Unfortunately, these will require pulling the transmission to rectify. You can try selecting first with the engine not running, making sure the front of the car is clear of obstacles. Then start the car in first, drive forwards, then cut the ignition. Try the pedal once more.

This sometimes works, and knocks the release bearing back into place, if it was misaligned on the release sleeve. You could be lucky.

Did you grease the input shaft serrations, and the throw-out bearing sleeve? Did you ensure the friction disc slide freely along the shaft, before it all went back together?

Well hopefully it’s a throw out bearing, I grabbed a spare when I picked up the slave yesterday. I did grease the shaft around the bearing but I did not check that the disc slid freely on the shaft. I actually didn’t even use a clutch alignment tool. I guess the engines coming back out to figure it out.

[Nollywood]

I never use a clutch alignment tool, but that’s neither here nor there.

It’s probably easier to pull the transmission to carry out any sort of clutch work.

I would still try my suggestion before pulling either engine or transmission though.

[mattg1.8]

I never use a clutch alignment tool, but that’s neither here nor there.

It’s probably easier to pull the transmission to carry out any sort of clutch work.

I would still try my suggestion before pulling either engine or transmission though.

Well as it sits right now i don’t have the driveshaft, axles, radiator, coolant, oil and a couple other things hooked up. I dropped it in and hooked up a couple hoses and electronics so at this point it would be more work to get it able to drive than it would be to just yank it out again.

[mattg1.8]

Got the engine pulled back out and tranny separated today. Upon initial inspection I don’t see anything wrong. There’s a little bit of play in the throwout bearing on the fork but that’s the only thing I can think of. How tight should the bearing be on the fork?

[zillarob]

Looks good to me.
Its a b7 pp, is that the fw that goes with it? Looks to be by the position of the fingers.

My guess is you missed with the rod. You have a metal slave? A plastic prob would have popped by now.

[Alex1188]

One thing right off the bat I notice is your SAC mechinism needs to be reset. That would cause an issue like your stating.

[zillarob]

Wants, but prob not needs. Id def do it while it was out though.
Those fingers look to be in about the right spot. They would have to be sitting on that metal ring to do what op is describing.

Missing with the rod is easy to do- rock hard pedal.
If testing it with the slave just hanging- rock hard pedal.
If testing the slave correctly, with somebody holding it compressed while you push the pedal, I think most would state that so we knew they were doing it right.

Im curious what slave he has. Guessing metal or would have blown it up by now. Although, blowing up a slave is pretty much a rite of passage in da b5s4 lyfz

[mattg1.8]

Wants, but prob not needs. Id def do it while it was out though.
Those fingers look to be in about the right spot. They would have to be sitting on that metal ring to do what op is describing.

Missing with the rod is easy to do- rock hard pedal.
If testing it with the slave just hanging- rock hard pedal.
If testing the slave correctly, with somebody holding it compressed while you push the pedal, I think most would state that so we knew they were doing it right.

Im curious what slave he has. Guessing metal or would have blown it up by now. Although, blowing up a slave is pretty much a rite of passage in da b5s4 lyfz

It’s actually a plastic Sachs slave. I never tried to force the pedal so I didn’t blow it. I’ve removed and reinstalled the slave at least 5 times and I feel pretty confident I got it in the right spot. If I compress the rod and have someone press the pedal everything works normal

[mattg1.8]

One thing right off the bat I notice is your SAC mechinism needs to be reset. That would cause an issue like your stating.

What’s the SAC mechanism and how do I reset it?

[mattg1.8]

Looks good to me.
Its a b7 pp, is that the fw that goes with it? Looks to be by the position of the fingers.

My guess is you missed with the rod. You have a metal slave? A plastic prob would have popped by now.

That’s what’s been installed for a while, before I had the car. There were no issues before I pulled the motor. Is there a specific way the pp or disc needs to be installed that I’m missing??

[vavJETTAw36]

You better clean off all that assembly grease from the input shaft/clutch/fw tines. That'll ruin a clutch disk and flywheel in short time.

[blitz2190]

if your installing the slave with the transmission in, you have to compress the slave rod or you'll miss the fork almost everytime and as other have said you'll have a rock hard pedal with the rod fully extended, got to shoe store grab those extra wide laces and use it to keep the rod compressed until the slave is in straight and pull the lace out before its fully seated, pro tip, cut the ends of the laces so its easy to pull out.

[vavJETTAw36]

if your installing the slave with the transmission in, you have to compress the slave rod or you'll miss the fork almost everytime and as other have said you'll have a rock hard pedal with the rod fully extended, got to shoe store grab those extra wide laces and use it to keep the rod compressed until the slave is in straight and pull the lace out before its fully seated, pro tip, cut the ends of the laces so its easy to pull out.

or ask the wife for some ribbon from her ribbon collection. Works everytime.

[Alex1188]

What’s the SAC mechanism and how do I reset it?

"SAC" = self adjusting clutch. You have to compress the pressure plate and rotate the ratcheting piece counter clockwise. There are plenty of DIY out there on how to do this. It may not be 100% of your problem but it could definitely contribute to it and severly effect the life of your clutch if you don't reset it.