Inconsistant clutch pedal pressure

[nates6969]

Hey guys I just bought a 93 tsi awd w/ an act 2600, which when first purchasing, the shifter was far out of adjustment. Before adjusting cable length I realized the cable bracket on the transmission was missing a bolt! replaced the bolt and the shifter shifted beautifully. Then one day the clutch pedal dropped and the pedal pressure almost completely deminished. Right away assumed the slave as my 91 talon has had the same problem before. Checked the slave under the boot and it was slightly wet so replaced that. Bled the system and the pedal pressure came back. Then after leaving the car for 30 mins the pressure diminished again and I had to pump it up to achieve pressure again. So I checked the master, also a little wet, so rebuilt that and also put in a ss clutch flex line.

This leads me to now, the system does not appear to be leaking anywhere but the pedal pressure is very inconsistant. I've adjusted the master linkage and it goes from having no pressure to have tons of pressure with a half turn of the linkage. however it seems when it has tons of pressure, the clutch feels preloaded. if I back the linkage off a hair then all of a sudden theres no pressure. or sometimes it goes from tons of pressure to almost no pressure just while driving?!

Anyyyyone have any idea whats going on here. The clutch bites hard and the TOB is not making any noise


Thanks in advance!

 

[nates6969]

Also I'm 95% sure the crank hasn't walked if thats what many are thinking as I have pulled on the crank pully with no noticable play but I will 100% confirm this sunday

...any other ideas?

thanks

 

[GSEclipse620]

This was a problem that I was having in my 95 gs, totally different engine and transmission but I assume the basic principles and construction of the parts are the same. No seemed to be able to figure this out for the longest time; Me(in auto tech classes) my dad(tractor mechanic), the dsmtuners folks who visited my thread took some swings but couldn't pick it out for the longest time, It evan stumped the guys at the mistubishi dealership. Anyways, idk if this is your problem but I'll post a link to my thread for the specifics, but long story short you may need to adjust your push rod coming off of your clutch pedal.
http://www.dsmtuners.com/forums/showthread.php?t=245926

 

[forcefed4]

Maybe worn/bent clutch fork or pivot ball? Sounds like you've done everything else, as long as the rebuilt master cyl. is good.

 

[nates6969]

ya I wondered if it was a bent clutch fork however if it was just bent it wouldn't explain the inconsistencies as you would think it would just be very difficult to disengauge as the actual clutch travel would be less.

This could be totally unrelated but I'm only seeing around 9-10psi of oil pressure at 800 idle (10w30 oil temp ~200F) but sometimes can drop to 5 psi for several seconds (rpms drop to 650ish), now I havent read much about low oil pressures associated with crankwalk but is this another sign of CW? as if it is, along with inconsistent clutch, I could be seeing a lot of work in my future!! !! regular cruising around 2500 rpm oil pressure is around 50-6psi...

someone tell me I'm just over paranoid!

 

[oldman]

Describe in detail the method you used for bleeding.

 

[nates6969]

when first installing master, i opened slave bleeder screw ~2 turns. I pressed slave rod completely into cylinder then before releasing I plugged the bleeder with my finger. I did this 4 times. This creates a vacuum pulling the fluid into the slave and eventually the air out of the master (lower density). then tightened bleeder and I pumped the clutch about 6 or 7 times then did the above method several more times. Finally for the last 2 bleeds I tighted the bleeder instead of using just my finger to ensure no air leakage through threads of bleeder.

I was inspecting an old master today and was noticing how little the piston must be pressed before preloading occurs. I think this may be half my problem as the master had an extended rod installed. I tried swapping it back to a stocker however I dont get nearly enough travel. The pedal assembly is welded although i sware it seems like there is still a half inch of pedal slop. I really dont want to tear out the transmission and am considering an extended slave instead of the master rod therefore no preloading of the master could occur

 

[nates6969]

Im starting to consider a bent shift fork again as when the clutch does not feel preloaded, there is consistent low pedal pressure even when the master is adjusted all the way before blocking the relief port. The only thing is the clutch fork looks centered in its left to right travel.

How common is a bent shift fork with a 2600?

 

[oldman]

You're bleeding it all wrong allowing air to re-enter the slave, re-bleed the system with a friend following the directions EXACTLY as written in this article. One thing the article didn't mention which is also crucial is not to open the bleeder too much, if you see fluid coming out of the threads of the bleeder vavle, you'll also suck air back into the system through the threads.

 

[xveganxcowboyx]

Half an inch of free play at the top of the pedal is spec. If it's entirely sloppy that may be different, but it should move freely about 1/2 inch before starting to engage.

I just did my slave cylinder and found 1/2 a turn to be adequate to open up the valve.

 

[nates6969]

ok I'll give that method a shot however before I developed my technique I had been doing the bleeding with 2 people, didn't use the vaccum line to prevent air from reentering though but I was careful. I'll give that a shot this afternoon though.

Thanks

 

[oldman]

ok I'll give that method a shot however before I developed my technique I had been doing the bleeding with 2 people, didn't use the vaccum line to prevent air from reentering though but I was careful. I'll give that a shot this afternoon though.

Make sure you re-adjust the master back close to the stock position before bleeding then re-adjust after bleeding if need be.

 

[nates6969]

Alight so did a 2 person bleed this afternoon and I backed the master rod off before bleeding. Then after bleeding, I adjusted the rod so it was definately not preloading however there was no peddle pressure at all yet the slave still travelled quite significantly. Then if you put it to the floor then quickly pull up, you can here the clutch fork 'slowly' retracting. I then adjusted the master a bit more and it made great pressure however now when trying to put it in gear the clutch doesn't seem to disengage at all and now realize I can here a light squeal from the TOB until I push in the clutch a little

 

[oldman]

I backed the master rod off before bleeding.

How far back? stock is about 4 threads showing.

Then after bleeding, I adjusted the rod so it was definately not preloading however there was no peddle pressure at all yet the slave still travelled quite significantly.

What do you mean by preloading?

 

[nates6969]

well my pedal assembly has no assist spring so I unlatched the small pedal spring and adjusted the rod until the pedal began to drop, therefore no pressure against piston.

the owner before me also put in an extended clutch master rod with several more threads. By preloading I mean the clutch pedal maxed to the top of its swing then adjusting the rod a bit farther causing the piston to press in slightly, blocking the pressure relief valve at the end of the master. once this gets blocked, the clutch "pumps up"

 

[oldman]

well my pedal assembly has no assist spring so I unlatched the small pedal spring and adjusted the rod until the pedal began to drop, therefore no pressure against piston.

the owner before me also put in an extended clutch master rod with several more threads. By preloading I mean the clutch pedal maxed to the top of its swing then adjusting the rod a bit farther causing the piston to press in slightly, blocking the pressure relief valve at the end of the master. once this gets blocked, the clutch "pumps up"

I wasn't aware the 1G has the pump up problem, I'm pretty sure that is a 2G thing but I could be wrong. Also, I have never heard of extended master rod besides welding an extra nut to the bracket to get more adjustments which is a terrible idea to begin with. I don't know why you're having such hard time and things are so complicated for you, I have done this countless time on other people's cars and it's a pretty straight forward process.

 

[nates6969]

ya the extended rod is bastically the same as the welded nut. I think I may have exhausted all "out of transmission" problems. I think it may be time to tear off the transmission! :S! I'm assuming the fork is bent and TOB is half shot. The ACT has been in there for almost 6 years so that kind of force has to have some wear on those components over time. I hope the clutch is still fine. Before this happened, the clutched grabbed so nicely!

 

[nates6969]

ok i know have consistent pedal pressure! the clutch no longer slips or gets pump up however i feel like i need another 1/4" of clutch travel as the gears are a little notchy. My slave does not seem like its not extending far enough. however close should the fork get to the bellhousing? right now i can stick my index finger between the fork and bell housing when completely pressed