Clutch Pedal Not Fully Returning After WOT Pulls

[PovGRide742]

Hello,

To start off with, these are the three stages and associated problems I had:
1. Original Clutch, Original Slave, Original Clutch Line, Original Master - No problems, installed until about 155,000 miles
2. VAST Stage IV Clutch, Original Slave, Original Clutch Line, Original Master - Clutch pedal wouldn't fully return (had to be manually lifted up) every now and then during hard launching, only started after roughly 15,000 miles
3. Clutch Masters FX400, Meyle Metal Slave Cylinder, USP Stainless Steel Clutch Line, Original Master - Clutch pedal doesn't fully return after every WOT pull (has to be manually lifted up) in each gear (verified in 1st, 2nd, and 3rd), installed for roughly 400 miles

Mike of Ringer Racing is thinking either the slave, master, or blockage in the clutch line causing a restriction of flow on the way back. I'm going to check the clutch line and ensure I didn't kink it (though I would think this wouldn't allow the clutch pedal to come fully up during normal driving also) during the reinstallation of my engine and then I'm going to rebleed the clutch this weekend, and then order a new master cylinder... but in the meantime I was wondering if anyone experienced this same problem and could comment on what it took to fix it before I go wasting my time or throwing money at parts I don't need.

Thanks,
Brett

[S4James]

the masters have been known to go bad, they are cheap plastic with rubber o-rings. not the most durable thing to look at. If this car has ever run non-spec brake fluid, such as super-blue i would be doubly suspicious. Mine got ruined by that junk.

They are a bit of a pain to replace, but not terrible. Hardest part by far is bleeding the lines after.

The masters are not expensive either.

[rtl5009]

if its driving ok, fuck it.

[S4tech2]

You've replaced everything but the master, that's the last week link right? Just for thought was the input shaft lubricated when the clutch was done? May have a spot on it that is catching the throw out bearing.

[rtl5009]

You've replaced everything but the master, that's the last week link right? Just for thought was the input shaft lubricated when the clutch was done? May have a spot on it that is catching the throw out bearing.

The pressure plate fingers push the fuck out of the TOB, the input shaft hanging the TOB would cause clutch slip and the pedal would get hard as a ROCK.

[S4tech2]

^ good point. Slap a master on thing and see what it does.

[OHS4]

Yeah I also have this problem, but my pedal is hard to push down and it also does not return as fast as it should. It has stranded me a couple times where I can't push the pedal down at all. One time it got stuff up, I parked it for a hour and it freed up, the next time it did it, I slowly pushed it pretty hard and it finally depressed. I do notice it gets worse after a WOT run. Could this be the same thing?

I also have a new master, slave and USP braided clutch line... (and a new clutch as of 20k ago)

[HighPsi(NorCal)]

Master, had the exact symptoms you described. I started having problems putting it in gear or out of gear after a few months of the pedal acting like the way you describe (this was the 2nd new oem master I had fail in a 6 month period). Upon putting in the 2nd new master, I have had zero problems for the last year, knock on wood...

[PovGRide742]

the masters have been known to go bad, they are cheap plastic with rubber o-rings. not the most durable thing to look at. If this car has ever run non-spec brake fluid, such as super-blue i would be doubly suspicious. Mine got ruined by that junk.

They are a bit of a pain to replace, but not terrible. Hardest part by far is bleeding the lines after.

The masters are not expensive either.

Well I ordered a master... we'll see what that does to fix it.

if its driving ok, fuck it.

Lol... driving okay doesn't mean everything is right, and I want it right.

You've replaced everything but the master, that's the last week link right? Just for thought was the input shaft lubricated when the clutch was done? May have a spot on it that is catching the throw out bearing.

The pressure plate fingers push the fuck out of the TOB, the input shaft hanging the TOB would cause clutch slip and the pedal would get hard as a ROCK.

^ good point. Slap a master on thing and see what it does.

I always apply a light film of white silicone grease to the input shaft, and certainly not experiencing any of those problem. Certainly appreciate the input though!

Yeah I also have this problem, but my pedal is hard to push down and it also does not return as fast as it should. It has stranded me a couple times where I can't push the pedal down at all. One time it got stuff up, I parked it for a hour and it freed up, the next time it did it, I slowly pushed it pretty hard and it finally depressed. I do notice it gets worse after a WOT run. Could this be the same thing?

I also have a new master, slave and USP braided clutch line... (and a new clutch as of 20k ago)

That's weird... completely different than my problem. My clutch pedal is easy to depress and seems to return as fast as any of my previous setups.

Master, had the exact symptoms you described. I started having problems putting it in gear or out of gear after a few months of the pedal acting like the way you describe (this was the 2nd new oem master I had fail in a 6 month period). Upon putting in the 2nd new master, I have had zero problems for the last year, knock on wood...

Sweet... glad to hear I'm headed the right direction. I just fear the bleeding, would have been nice to do while the engine and transmission was partially out of the car. Haven't really ever looked at the slave positioning with the engine and transmission completely in the car, and can't quite picture it... easiest to access the bleeder screw from up top or below?

[HighPsi(NorCal)]

^I was on a lift, from the bottom was easiest for me, though I have read responses about people having replaced and bled the slave from the top.

[S4James]

i bled from the top (no lift) and its a shit job. Really shit. Especially with no help.. Worked out a system witha couple of hockey sticks to work the brake pedal. Thought my arms were going to fall off by the time i was done.

less than a month later my motor quits for no good reason and the whole shebang had to come out anyways.


FU car.

[Delmed83]

I did the whole slave job from top (besides R&R of the one bolt). Bleeding it was simple after using the JHM instructions. Clutch pedal feels way better now. However, I think I may need a new master, too.

[PovGRide742]

^I was on a lift, from the bottom was easiest for me, though I have read responses about people having replaced and bled the slave from the top.

I CAN do it on a lift... but I may just gravity bleed it so if I can just put it on ramps and stands, with the ass end up higher obviously, and reach the bleeder from underneath I might try and reach the slave from underneath.

i bled from the top (no lift) and its a shit job. Really shit. Especially with no help.. Worked out a system witha couple of hockey sticks to work the brake pedal. Thought my arms were going to fall off by the time i was done.

less than a month later my motor quits for no good reason and the whole shebang had to come out anyways.


FU car.

Sounds like your typical S4 relationship. I'll have a second person to operate the clutch pedal... and I'm gonna try to access the bleeder from underneath.

I did the whole slave job from top (besides R&R of the one bolt). Bleeding it was simple after using the JHM instructions. Clutch pedal feels way better now. However, I think I may need a new master, too.

Luckily I don't have to replace the slave (replaced while I had the engine and transmission out)... just bleed it after replacing the master.

[willisan]

OP, was it the master? Same thing happened to me tonight after a WOT pull. Couldn't engage in 2nd or 3rd and clutch pushback was almost non existent.


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[PovGRide742]

OP, was it the master? Same thing happened to me tonight after a WOT pull. Couldn't engage in 2nd or 3rd and clutch pushback was almost non existent.


Sent from my iPhone using Tapatalk

It did not fix it. Every now and then the clutch pedal doesn't still return after a WOT pull to redline. So with a new clutch (CM FX400), new flywheel (CM steel), new slave cylinder (Meyle metal (swapped rod from stock cylinder)), new clutch line (USP stainless), and new master cylinder (FTE)... it still doesn't always return.

So it could be (and obviously not limited to):
* Blockage in clutch line (or kinked)
* Not enough lube on throw-out bearing (maybe?)
* Bad brake master cylinder (maybe?)
* Problem with clutch

[Mille Bornes]

Any progress towards a solution? I have the same clutch and it's doing the same thing. Is it hard for you to get into gear once the clutch stops returning?
I haven't had many opportunities to log 0-60 or 1/4 times but I've tried a few times and after I launch and the clutch stops coming back up on its own it's kinda hard to get into the next gear so my times suck lol.
But it's not only when I launch, even when I go WOT from a roll it stops returning.

When the pedal stops returning like that it's also real tricky to start from a standstill but then as soon as I pull the pedal up everything is completely normal. I have no idea, especially seeing everything you tried to no avail, and it's ruining my fun lol

[ADKWrench]

Something is stopping the pressure plated from engaging. Its probably the throw out bearing hanging up..

I'd try to make it hang up, then possibly get a peek at it through the bellhousing..and crack the bleeder on the slave..if it then engages and pushes the throwout back then it somewhere "up the line"

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[rtl5009]

It did not fix it. Every now and then the clutch pedal doesn't still return after a WOT pull to redline. So with a new clutch (CM FX400), new flywheel (CM steel), new slave cylinder (Meyle metal (swapped rod from stock cylinder)), new clutch line (USP stainless), and new master cylinder (FTE)... it still doesn't always return.

So it could be (and obviously not limited to):
* Blockage in clutch line (or kinked)
* Not enough lube on throw-out bearing (maybe?)
* Bad brake master cylinder (maybe?)
* Problem with clutch

thats frustrating

[julex]

This is obviously boost related so I have a feeling that somehow (broken check valve?) your brake booster might be getting pressurized and somehow that might be pressuring the hydraulics for brakes/clutch as they are shared. Do a test. Hook up your boost tester, shoot as many PSIs as you're normally getting (or as close as you can) into the intake and see if your clutch is misbehaving. If it does, you will have to test/replace the brakes boost tube going into the firewall or at least fix the check valve in there.

[rdcyclist]

This is obviously boost related so I have a feeling that somehow (broken check valve?) your brake booster might be getting pressurized and somehow that might be pressuring the hydraulics for brakes/clutch as they are shared. Do a test. Hook up your boost tester, shoot as many PSIs as you're normally getting (or as close as you can) into the intake and see if your clutch is misbehaving. If it does, you will have to test/replace the brakes boost tube going into the firewall or at least fix the check valve in there.

That would be a great idea but how would it pressurize the hydraulic system? I'm trying to picture the process and coming up empty (could just be me having an empty head...). Fairly easy to test without going to all that crap; go out, do a WOT pull and hit the brakes with the throttle down. If the booster's pressurized, you'll get no brakes.

[julex]

That would work to test the basic idea.

A boost leak test, the standard variety, will for all intended purposes replicate car having intake tract under boost. This way you can keep it pressurized and actually have all the time in the world to test the boost line. The check valve is before the connector (or in it) that plugs into the firewall. If you disconnect it and air starts blasting out, then that would probably be the culprit here... and the clutch should be as limp as male sex organ after a busy night.

[rdcyclist]

I like my way cuz it means I get to do another WOT pull...

[Mille Bornes]

lol I'm gonna go try the WOT pull method. I was gonna do some logging and I'm a little afraid to put 22psi to the y pipe. I've pressure tested up to 15, which I think would be sufficient to find leaks, but I'm scared of my inlets blowing off lol. I have the FrankenTurbo inlets and my set wasn't even close to fitting right so I used silicone couplers to connect to the turbos.
If it was as simple as replacing that valve I'd be elated. I might just replace it regardless of what happens during the pull lol.

I can't think of anything else (like TOB hanging up) that would only happen after a WOT pull.

[Mille Bornes]

Well, I definitely have breaks at WOT. I also noticed that the clutch pedal is normal after WOT unless I run it out to redline

[$teady$upreme]

maybe the fork or throw out bearing?

[zillarob]

See if the clutch slips when the pedal doesnt come back.
Might be a clue to whether or not it is in the bell housing or somewhere else.

[Mille Bornes]

maybe the fork or throw out bearing?

I've considered this but I can't imagine why they would only cause problems after a high rpm, wot pull.

See if the clutch slips when the pedal doesnt come back.
Might be a clue to whether or not it is in the bell housing or somewhere else.

It doesn't slip. I didn't even notice it wasn't coming back until I went back to regular driving after doing some runs and found it hard to start from a stop.
It's also somewhat difficult to get my car into gear, pretty much any time although it's most noticeable when I'm WOT and trying to shift fast. It might be an issue with the shifter being adjusted properly but I can go through all the gears real fast if I'm sitting still with the clutch in.
But when driving, and especially doing runs, it just seems reluctant. Like, if I'm in first going for second, I have to keep holding the shifter pull into second for a little while until it'll go in. It's like, when you start going into the next gear and I assume what youre feeling is the synchros (i'm not a tranny guy) bringing everything up to speed maybe. It's like they need some extra time lol

I don't know if both of these problems are related or not. The being hard to get into gear is definitely worse when the clutch doesn't return all the way. I've actually had cases where I couldn't get into gear at all until I pulled the pedal up.

I might email clutchmasters and see if they have any idea.

[Mille Bornes]

I haven't heard from Clutch Masters yet but I think I'm going to replace that check valve. While searching for boost leaks for the millionth time I noticed brake fluid on my reservoir which had leaked past the cap. Just a very small puddle but I've never opened my brake fluid reservoir before, haven't compressed calipers for any reason and I know that wasn't there awhile ago.

[Mille Bornes]

Quick update on this issue. I just talked to a guy who owns a local European performance shop and he said that he's pretty positive the pressure plate has cracked and that's the cause of my issue. He said he's seen that a lot with ClutchMasters and it usually occurs early in the PP's life, as it did with mine. I haven't pulled the clutch to verify but it makes sense to me. Hopefully when I do pull the clutch I'll be able to get a refund as I'd like to go South Bend next time.

[james 408]

just a thought: if you can replicate the issue while it is parked (or use a camera while driving?)... you could watch the slave to see if it's building pressure appropriatly (like when you bleed it) or whether it's not getting enough pressure for some reason (master cylinder side of things issue). whereas if it's clutch related, the slave would be pressurized it just can't push the pedal back because of a mechanical hangup (transmission side).

[PovGRide742]

Haven't posted in this for in a while, but a few things to note to address what some people were commenting on...
1. The clutch does NOT slip when the pedal doesn't fully return.
2. The other night at the track I was having problems getting into 4th, and this seems to be common when I start from a dig and go through all the gears into 4th without lifting the pedal back up... and I do have to lift the pedal back up at the end of the run. (I haven't had problems with this aside of this issue, so I can't say whether this is a shifter alignment issue or not)
3. I have NOT had problems with the clutch not coming all the way up during bleeding.
4. I can NOT duplicate this problem when stationary. It only happens after revving out the gear. It happened this morning flat-shifting from second into third.

Brett

[GramCracker]

Anyone happen to have a writeup on replacing the master cylinder?

[RedB5S4]

Anyone happen to have a writeup on replacing the master cylinder?

stfa, noob

[Mille Bornes]

So, I am in the middle of replacing my clutch right now. I've replaced the master, line, and slave. The only thing left is the clutch and I was advised that a cracked pressure plate is likely.

Well, I don't see anything wrong with the pressure plate just yet. However, my pressure plate bolts came loose. I have no idea how. I torqued everything to spec as per the Bentley instructions. Was there supposed to be Loc Tite on the pressure plate bolts? My flywheel bolts came with Loc Tite but the pressure plate bolts didn't so I assumed it wasn't required for them.

Has anyone else had this happen? Also, should I be using a torque spec other than that provided in the Bentley?

I'm really on the fence about what to do. I don't see anything wrong with the FX400 pressure plate so idk if I should reinstall it or install the new Ringer Racing Stage 4 that I have sitting here. I'd hate to toss out a clutch with only 4k miles on it but I also really don't want to do this a third time.


I'm pausing for lunch right now so any quick insight is appreciated! The motor has to be sitting back in the car by the end of today so I'll probably toss a coin or something in 20 minutes or so lol

[Monty23]

Def use some loctite on those pressure plate bolts. I hear the FX400 has a short life (10-15K miles) so I would definitely go with the new clutch if you don't feel like doing your clutch in less than 10k miles from now.

[y3ti]

I dont see anything about loc tite mentioned for the pressure plate, but it couldnt hurt.

Tighten the bolts gradually in a diagonal sequence up to 22nm.

[Monty23]

You should also make sure your torque wrench is within spec. Might be time to get it calibrated.

[Meow]

Haven't posted in this for in a while, but a few things to note to address what some people were commenting on...
1. The clutch does NOT slip when the pedal doesn't fully return.
2. The other night at the track I was having problems getting into 4th, and this seems to be common when I start from a dig and go through all the gears into 4th without lifting the pedal back up... and I do have to lift the pedal back up at the end of the run. (I haven't had problems with this aside of this issue, so I can't say whether this is a shifter alignment issue or not)
3. I have NOT had problems with the clutch not coming all the way up during bleeding.
4. I can NOT duplicate this problem when stationary. It only happens after revving out the gear. It happened this morning flat-shifting from second into third.

Brett

This is exactly what happens to me. Ive been through several slave cylinders and think its just a pedal issue. Others have had this as well and we all just end up saying the same thing:

if its driving ok, fuck it.

And we just keep driving it.

[Monty23]

This is exactly what happens to me. Ive been through several slave cylinders and think its just a pedal issue. Others have had this as well and we all just end up saying the same thing:
And we just keep driving it.

RedB5S4 is having this issue right now as well. He thinks he kinked his clutch slave hardline when pulling his motor... he is planning to install a metal slave and braided line.

[Meow]

RedB5S4 is having this issue right now as well. He thinks he kinked his clutch slave hardline when pulling his motor... he is planning to install a metal slave and braided line.

I spent a lot of time investigating why it happens and I can duplicated it occasionally with one specific act: Launch control. I can not 100% duplicated it consistently but I can do it pretty reliably at over 50% of the time I use launch control my pedal gets odd and then doesn't come all the way back up and I have to pull it up with my foot.