Clutch still slipping

[northoceanbeach]

Ok, this is like my millionth post on this but I still can't figure it out. But there is progress. I'll start with the history. Keep in mind I am a very, very beginner mechanic here. The most work on a vehicle I have ever done is what I have done to my new(ish) landy.

OK in short summary I bought 1973 SWB. Had towed to house. No clutch pressure. Put in new clutch master and slave. Added fluid. Had pressure. Drove. Noticed cluthc was slipping. Sliiping got worse. Bought and installed new clutch, pressure plate and throwout bearing. The clutch I took out was old, worn down to the rivets. No oil contamination in there. Very dry. FLywheel looked good, but I have never seen one before. CLutch job seemed to go smooth. Took a test drive. Still drovde the saem, still slippage.

!!I think this may be important. When I put in gear and let off the clutch, it doesn't move forward until the pedal is pretty much completely released. It doesn't even begin to roll forwad until the clutch pedal is at the very top. So what I was guessing is that something is keeping the clutch is ever fully engaged.!!

So the other day I bled the clutch in case I had air still in there. And I did, alot of bubbles came out. I also the same day tried adjusting the linkage where the pedal connects to the master cylinder. I then put on a new flex hose.

After doing those three things it got better. It doesn't slip as much, not at all, very noticeable difference. But going up hills it still does slip.

I am kinda encouraged that it got better. But I have no idea what I did that helped. Or how to make it stop slipping completely. Any ideas?

A neighbor came out, and he know a bit about cars, but said he never really worked on a hydraulic clutch before but he mentioned these possible causes. I'll throw them out there in case they sound likely.

1. I got sold a too thin clutch

2. the slave cylindar pin is too long and always holding the clutch arm a little off the flywheel. He said I could maybe take the slave off and put spacers so it is held a little farther off the transmission.

3. there is always a little pressure in there. He said it can happen when cable clutches that there is always some tension.

What would you guys try? Think I should bleed more that there may be some air still in there that is hard to get out? It looks like the master linkage is adjusted right, It appears to have free play. THe bolts are pretty close to the tip of the master cylinder pin and they are tightened around the top of the pedal. I really don't have any other ideas.

As always, thanks for any help.

[Clive]

You seem to have tackled most things so this sounds like a frustrating mystery because the clutch is pretty straightforward (having had the one in my 73 SIII in and out about five times for various, non-clutch related issues).
To me it sounds as if your clutch is not fully engaging for whatever reason. It has to have a straightforward mechanical solution so it would appear that short of someone offering that going back to basics may be the only way to track the fault down:

1. Is it the correct clutch/pressure plate and combo? What diameter (I recall there may be a couple, 9" and 10 "??)? Someone else may be able to shed more light on that.
2. Was the clutch put in the correct way around? (shouldn't work at all if it wasn't!).
3. Was the clutch aligned correctly using a clutch alignment tool or equivalent before tightening the pp? (again, this would be an unlikely cause as the the shaft wont really fit if it is not...)
4. Torqued everything properly?
5. Is the slave cylinder rod the correct length/right way round?
6. Is the lever for the thrust bearing in the bell housing set up correctly and able to move the full distance (ie not being blocked by something)?
7. Is pedal height and push rod on master cylinder correctly adjusted. If these are severely out of whack it would have the effect of riding the clutch (ie, it would slip). The push rod here is critical, and awkward as hell (as you probably discovered weeks ago).

Based on what you have done already 6 or 7 would appear the most likely. Can you post any photos of it? What about the measurments of the rods and clutch settings?
Why was there air in the system after you bled it? Where is it leaking in? Although that would make it difficult to dis-engage the clutch, it would not cause it to slip, but you'd crash your gears...

[scott]

i am feeling your pain (slippage). i'm in the middle o a clutch job myself.

- there are 9" an 91/2" clutches and prs/plt. you can't/shouldn't mix these sizes. use a 9 w/ a 9 or use the 9 1/2 w the 9 1/2.

- adjust the lingage below the slave so that you get the right travel and when at rest the t/o bearing is applying no force against the prs/plt.

- the dude who did the last clutch job on mine forgot to remove the spring retaining clips. mine has 3 on the back side of the prs/plt and they're red. if not removed after install the full force of the prs/plt won't be felt by the clutch slippage may occur, clutch life will be short.

- you should always have had the flywheel turned

- i'll post pictures tomorrow or wednesday.

[scott]

http://www.roversnorth.com/forums/at...1&d=1173147186 this is my old prs/plt the arrows point to the clips that were never removed
http://www.roversnorth.com/forums/at...1&d=1173147186 here's a close up

[Clive]

SIII 1973. I installed a new clutch and pressure plate 1 y ago when I did a bunch of engine and transmission work and never removed any "tabs" from the pressure plate...the clutch seems to work fine, no slippage....
It doesn't say anywhere in the Green Bible or the Haines manual that you should remove anything from the pressure plate on installation, and not being a swami I did not. Where can I find out more about this and do I need to remove my transmission (again!) to get at the pressure plate and remove these "tabs" from the pressure plate springs? That would be a real bummer. My transmission and I do not get on well.
Are all pressure plates the same (SII, SIII etc OEM, Borg&Beck?)?? Help. Many thanks.

[Dav1550]

Not sure if this would relate...... I had an initial problem with the clutch slipping after a rebuild on an SIII

To be more precise the clutch plate was not fully engaging..... It would start out just fine but after clutch peddle was depressed and released a few times the clutch master cylinder was not fully releasing the pressure on the line to the slave...... Hence the clutch would start slipping in short order once underway.


Suspect that I've got the adjustment off where the peddle attaches to the master cylinder.... But was able to get it sorted for now by adjusting the clutch peddle 1" higher than what the manual call for.

Dave

[jp-]

http://www.roversnorth.com/forums/at...1&d=1173147186 this is my old prs/plt the arrows point to the clips that were never removed
http://www.roversnorth.com/forums/at...1&d=1173147186 here's a close up

Scott,

Those are assembly bolts for the pressure plate. Do NOT remove them. That is why they have locking tabs on them.

If you wish to test your pressure plate to ensure that is working correctly, place it on a flat surface (with the side up as shown in your first photo) and stand in the center of it. I weigh 185 and with a slight bounce, the pressure plate will spring open and then closed. So basically, a pressure plate in good working order should provide in the neighborhood of 200lbs of resistance.

[jp-]

..... It would start out just fine but after clutch peddle was depressed and released a few times the clutch master cylinder was not fully releasing the pressure on the line to the slave...... Hence the clutch would start slipping in short order once underway.

Dave

Dave,

This is an excellent observation, and was pointed out in the first clutch slipping thread. Although, my experience was with a CV master cylinder for the brake system. If this is the problem it should be very easy to check.

Northocean,

To test this, pump the clutch pedal up several times and release. Wait about 30 seconds, then open the bleed screw on the clutch slave cylinder (you might want to have a hose on the bleed screw). If fluid blasts out the bleeder, your master cylinder is not realeasing the pressure.

[scott]

jp

this is a quote from the mfg of the prs plt i just installed

"Certain coil spring cover assemblies are fitted with despatching staples or spacers, normally painted red, between the levers and cover pressing, these should be removed as the cover assembly is bolted up to the flywheel. During cover assembly removal from the flywheel spacers should be simarly replaced to avoid the mounting bolts leaving the flywheel while still under pressure." A.P. Borg & Beck

the pictures of the old ain't red but on my new one they are. i read this to mean put on the prs/plt remove the spacers and put 'em back before removing the prs/plt next time. i think the spaces rmoved increase the pressure on the clutch and therefore hold tighter.

[jp-]

Scott,

The spacers are not generally used on diaphragm type pressure plates, only on borg & beck types and long finger types. The Rover one is a diaphragm type.

The spacers go between the fingers (lever arms) on the other types. You should not have to unbolt anything to remove any spacers (i.e. spacers should not be bolted on). These spacers are only removed (on the two types mentioned above) when the pressure plate is tightened onto the flywheel. If they were not in place, the mounting bolts wouldn't be long enough to grab the flywheel.

http://www.competitionplus.com/03_25...tch_univ2.html