high rpm clutch sticks to floor

[jonsusoju]

replaced blitz active clutch (single) that previous owner was running. that was a pain in the buttocks.

currently running ACT 6 puck heavy duty with prolite flywheel. while i was at it, i replaced oem nabco clutch slave with duralast slave cylinder (lifetime warranty) and connected clutch master to slave with steel braided line.

I am NOT running through dampening box. i had enough of that shit and learned my lesson early on with air getting into the system and being stranded.

clutch fork has about 5mm of play left and right. decided not to change it.

noticed small amount of tranny fluid leaking after clutch install. came from under the shifter area so i threw on a new oem upper trans shifter gasket and the trans fluid eventually slowed to about 3 small drips over the span of a night. I also park on a steep hill and could have overfilled... i put a new rear main seal to that can't be cause of leak...either way, i know the sr20det is getting old and i can expect the occasional leak here and there so long as i keep an eye on the levels.

during the clutch swap had to silicon the part of the transmission holding the input shaft. looks like this if i'm not accurately describing it:

http://www.tune2win.com/_useruploads/images/diy-tech/SR20swap/sr20.jpg

literally took off the while old part and silicon'd a new one on. it looked like a plate and a shaft attached...for lack of mechanical terminology.

spencer at sideways performance helped me with that, they were a great help to my whole clutch ordeal and had the part.

shifting feels solid, a bit notchy at cold start.

this is my daily and its been fine and dandy since the clutch replacement about 850 miles ago.

today I decided to push my car past my usual daily threshold of 3000-3500rpm (usually when boost kicks in, running 13 psi on s15 turbo). i was at about 4700 in 3rd.

as soon as I let off the gas to shift up (from 3rd to 4th), i pushed in the clutch pedal and it stuck to the floor. obviously I couldnt shift since it was stuck. I naturally decelerated since I went to neutral and had to manually lift my pedal from the back. i dropped down to 3000rpm and my clutch pedal reengaged perfectly fine. I shifted at lower rpms (3-3500) and the clutch pedal returned perfectly fine.

I parked my car for around 7 hours at work then started it up to drive home.

clutch felt fine, no odd engagement feeling (not spongy). i gave it a few pumps for good measure before i left the parking lot. street driving was fine, below 40mph and sitting in 4th.

I decide to see if i could replicate the earlier phenomena. keep in mind i had been driving for 12 minutes already. I pushed to 4700-5000rpm again in third and attempted to shift up. clutch pedal stuck again and i had the same thing happen to me, just like earlier in the day.

i considered a new master cylinder, but since this problem only happened to me at higher rpm, I think it has something to do with my transmission. if it were a clutch master cyl problem, i would be getting this problem throughout the rev band. (?)

any help on this matter would be great. i actually want to enjoy my car once in a while.

if you need any other info, ask away.

[jonsusoju]

bump. this issue comes up erratically not following any pattern.

[Socalgal]

Ima bump this to ask if you ever found a solution. My pedel sticks about halfway up when springing back only sometimes when shifting at higher rpm's

[nissanracer29]

I also have the same problem. Maybe its the slave cylinder?

[Socalgal]

To elabarate my car has a new (all be it used but lightly) OS giken super single clutch kit, nismo slave, and braided stainless line that bypasses the damper. All fluid was replaced with approiate fluid and the system flushed on different occasions. pedel has also been adjusted per FSM.

All that's left is the clutch master cylinder and clutch pedel assembly bushings and return spring. I will be replacing all those parts within the next day or two. If this doesn't fix it it kinda has to be either the pressure plate or tob binding and ima flip out if this trans needs to come out again.

[racepar1]

Replace the master cylinder. I've had a master cause a similar issue before on my old fastback.

[jonsusoju]

never found the source of the problem. the only way to solve it is to get an entire new clutch assembly (+ new clutch fork, mine had a lot of play), new master, new slave. new clutch helps also. no real improvements are seen with the stainless steel lines. they can cause more problems if you don't purchase them new. 240's are old ass cars and the assembly must be worn to hell after 1-200k miles. i am with a z33 now so i am happy :-D.

[bbsanchezi]

this to ask if you ever found a solution. My pedel sticks about halfway up when springing back only sometimes when shifting at higher rpm'shttp://www.smecenter.net/aijie/images/2.gif

[Socalgal]

I wanted to update:

While replacing the master cylinder and rebuilding the clutch pedal I found the bushing that sits inbetween the pedal itself and the return spring had been missing long enough that the spring had eaten quite a bit into the pedal. I tried to have the pedal re-welded but it wasn't shaped perfectly so the spring is actually poping and it killed the new bushing.

New pedal was only 35$ from west Covina Nissan so I wish I hadnt waisted money on the weld.

And for anyone going to rebuild there pedal there is a lot more then 3 bushing in there (for s14 anyway), I'd do them all.

New pedal an all new bushing go in again tonight allthough I'm pretty positive this isnt going to fix the problem.

The pedal throw is completely smooth when the car is off. Once started the pedal feels almost gritty and the faster the motor goes the stickier it gets. Everything is brand new and the only thing this can be is the pressure plate (in my head anyway)

[dreimers]

Bumping an old thread, this is exactly what my car is doing now. I have replaced the tob, clutch release sleeve, springs, slave cylinder, master cylinder, ss line to slave, no dampener, I have bled this system until I got fluid. Normal rpm 3-3500 shifts fine pedal has pressure and engages and returns all good. The times I wanna run it up in the RPM pedal sticks...I am at a loss of what it can be. Need some help on this

[mechanicalmoron]

Bumping an old thread, this is exactly what my car is doing now. I have replaced the tob, clutch release sleeve, springs, slave cylinder, master cylinder, ss line to slave, no dampener, I have bled this system until I got fluid. Normal rpm 3-3500 shifts fine pedal has pressure and engages and returns all good. The times I wanna run it up in the RPM pedal sticks...I am at a loss of what it can be. Need some help on this

Grease?

fork worn so when the TOB is at max extension, it can cock sideways and bind?

Pressure plate binding?

Take it off.

[dreimers]

I did grease everything before I reinstalled the trans. I did inspect everything before I reinstalled the trans. Put new seals front and rear and a new pilot bushing also.
Nothing was making noise or looking any different when I took the trans down. I spun the motor over by hand just to be sure nothing was binding. I did not replace my fork, but it does seem to be working correctly. My slave moves it fully and it does not seem to move around at all when clutch is depressed and released.
This is why I’m at a loss of what else could be going on.

[mechanicalmoron]

How does the lever feel when the pedal sticks? shifts into whatever gear you put it, like the clutch is really fully released?

[dreimers]

fork worn so when the TOB is at max extension, it can cock sideways and bind?

I did notice before i put the trans back in that when i did install the fork w the new tob and new spring clips that if I extended the fork as far in the opening as it could go that my TOB would get stuck on the input shaft every now and again. This is one of the reasons i got a new clucth release
sleeve
Is this what you mean?

[dreimers]

not able to shift into a gear. I will shift into a gear and if its at higher than roughly 4000 rpms the pedal will stick to the floor and i have to pull it back up. Clutch pedal feels fine especially if i shift at lower rpms. Good pressure feel full engagement and release.

[mechanicalmoron]

not able to shift into a gear. I will shift into a gear and if its at higher than roughly 4000 rpms the pedal will stick to the floor and i have to pull it back up. Clutch pedal feels fine especially if i shift at lower rpms. Good pressure feel full engagement and release.

You've got air, or something like that going on.

I don't know the RPM connection to the pedal sticking, but your syncros are blocking you.

Compare old and new cylinders for having enough stroke or being positioned right to actually do the job?

I forget if this has one, but some clutches have a little boot/cap/cushion on the cylinder pushrod, which can go missing and cause trouble. Or sometimes the new pushrod just isn't quite right.

I mean, take if off one piece at a time, obviously if the slave is the problem don't proceed with pulling the tranny.

[p00t]

Could be because you are pushing the clutch in too far. If that is the case it is a situation called "over center" or "overcentering".

Two options: 1. Reduce and adjust clutch travel so that it releases fully just before the floor stop. 2. Use a helper spring attached to the pedal to assist it in returning.

I have or have had KA and SR act hd pressure plate and 6 puck disk without the damper line and pedal travel was reduced a bit after properly adjusting. Never had the issue.

[dreimers]

Could be because you are pushing the clutch in too far. If that is the case it is a situation called "over center" or "overcentering".

Two options: 1. Reduce and adjust clutch travel so that it releases fully just before the floor stop. 2. Use a helper spring attached to the pedal to assist it in returning.

I have or have had KA and SR act hd pressure plate and 6 puck disk without the damper line and pedal travel was reduced a bit after properly adjusting. Never had the issue.

I have a s14 the only stop there is , is the clutch safety switch. I also have a stage one Exedy clutch w a Fidanza flywheel. Same set up I have always had. Never needed a helper spring... Thank you for the info and I will have to check to see if it is overcentering

[mechanicalmoron]

Could be because you are pushing the clutch in too far. If that is the case it is a situation called "over center" or "overcentering".

Two options: 1. Reduce and adjust clutch travel so that it releases fully just before the floor stop. 2. Use a helper spring attached to the pedal to assist it in returning.

I have or have had KA and SR act hd pressure plate and 6 puck disk without the damper line and pedal travel was reduced a bit after properly adjusting. Never had the issue.

Yes - but then the clutch would disengage.

[dreimers]

Yes - but then the clutch would disengage.

Ah, very true. Still need to rebleed as you suggested.

[dreimers]

Found that my SS clutch line had a pin hole in it. I replaced the line, bled the system and adjusted the clutch pedal return. It now shifts pretty good, sometimes a little notchy. I did stick once on the hour plus drive i took it on. Lots of stop and go. No highway speeds. When I did stick i was shifting into 3rd at 5k or a little higher. Below that no issues. The pedal feels soft, atleast softer than I would think or like