This is in the cavalier. I tried moving the car sat am and was shocked when the car lunged backwards and stalled when I tried to put it into reverse. At the time I just said F it and switched to yard work.
Tonight I discovered that If I put the car in gear and partially depress the clutch pedal the clutch will disengage and allow the car to roll. If I continue pressing it in it will like grab again (or bind or something) and the car will no longer roll.
WTF is going on here?
I have an adjustable slave cylinder actuator rod, but messing with that would only change how much “auto adjustment” the hydro system has. I have no master pushrod adjustments, or pedal adjustments.
Im thinking I can just add a pedal stop, but Im not sure if that solves the problem or just masks it.
there isnt some sorta poppit in line with the master that prevents too much pressure is there? i could see over presssurizing and then the poppet bleading off access pessure causeing a slight engagement. presuure plate contacting flywheel would need a ton of stroke from the slave and seams a bit unlikely.
Ya, at first I was thinking it was over extension of the pressure plate causing the fingers to contact the clutch disc hub.
Now, Im leaning more towards an issue with the pressure.
There is nothing in line between the master and slave that could cause a pressure bleed. Im using an aftermarket external slave from CNC brakes and a 24" -3AN line. Im going to put my brake pressrue gague in the slave bleeder tonight and see if its losing pressure further into the stroke causing it to re-engage.
Apparently Im not the only one with this issue. There is another guy who is having the same issue in his Fiero. So far he is just dealing with it by not pushing the pedal in all the way, lol.
Sounds like a mechanical problem with the pressure plate/clutch disc. Do you have a sprung disc? If so it’s possible that one of the springs popped out of the disc. Also what brand clutch do you have?
I’ve installed a clutch where the slave travel was enough to push the fingers into the friction disc, but you’ll actually “feel” it and hear it as well. The only way I could see that mechanically causing engagement is if the fingers were to actually catch on the springs on the hub, but once again, that would probably break stuff and you know it clear as day.
So, my thinking behind this as a possiblity as to what is happening is that you may have a broken ring that retains the pp friction surface. I have seen this in the past and few times and usually it will cause poor/random engagement heights and in some cases no disengagement at all. I’ve never had the exact symptoms you described but I could picture the slave over extending the fingers on the pp and a broken ring (giving way/flexing) then pushing the friction surface back into the disc/flywheel causeing reengagement. If it comes down to you uninstalling it, check the pressure plate for that ring being possibly broken. It will be very difficult to pinpoint and everything will appear perfect, but a close inspection may reveal that it is indeed broken.
Sounds like that’s more than likely your problem. I have seen many spec/competition clutch/ebay clutch kits pop springs out as well as have their throw out bearings fail.
I cant believe the springs would have popped out with 0 miles. I literally havent driven this yet. The first time I tried to disengage it, is when it was actually “re-engaged”
I verified the slave cylinder tonight. It always moves out when the clutch pedal is going in, just like expected. There is 7/8" of slave cylinder acuator rod movement. Perhaps that is simply too much?
Oh in that case, not sure if you listed that before as I skimmed the thread. Sounds like you have too much movement, I read you have an adjustable slave rod but no adjustment at the master? That’s odd. Normally you would have adjustment at the master so you can change the pedal height and engagement. I take it your slave rod is stock then?
THe slave is aftermarket. Its a generic CNC brakes unit that I adapted to my trans a few years ago b/c I switched trans years which uses a different external slave. Going to the CNC unit was cheaper and “nicer”. It has an adjustable pushrod (which really only helps with initial installation).
The master is still stock. There is no adjustment here either. Basically there is NO factory adjustment.
Perhaps its time to finally install the CNC brakes master cylinder I’ve had sitting here for a couple years. Then Id have the ability to make some adjustments.
EDIT: Also the engagement is very high on the pedal. The clutch is basically fully disengaged by 1/2 travel (or so).
mark told me about this a few days ago. I was gona ask if you used a mighty vac to bleed it? I have no idea how the master is, but some if you apply to much vacuum its possible to roll the seal, so its cupped facing the bottom of the bore. And could be hitting that, or a stop that could cause it to dump pressure and apply the clutch. I just know the insides of LSx masters, but this came into my head. Sounds like it has a lot more travel then needed too?
on 99 civic reply, Could the PP fingers over extend do that? I don’t think the disc could get reached with anything in the middle around the input shaft, but I work on bigger clutch stuff.
You have any dust covers or anything to see in there? Bore scope with the starter out?
Studderin: Good idea on the bore scope. I was able to look at the TOB and PP fingers with the starter out (using a little mosaic mirror I stole from the wife taped to the end of it). There doesnt appear to be any issue with the TOB or PP fingers, all looks fine throughout the travel.
With the car jacked up and in 4th gear I had Becky push the clutch pedal in slowly while I turned one wheel. I was easily able to tell when the clutch was completely released, both by the release of tension and the change in direciton of the opposite wheel. It definitely completely releases, somewhere about 1.5" from the end of the pedal travel which isnt so bad.
So Im just going to make a pedal stop, adjust it to be completly released at full travel, and call it good enough for now.
Just finished putting everything back together including a pedal stop I made up quick. Now, with the pedal on the stop I can freely roll the car. It may need some adjustment but my helper went to bed a long time ago. Ill do the spin the wheels test, and then once its running I can further test it by revving the crap out of it in gear wiht the clutch pedal in and see if the car starts moving.