Clutch releases too close to floor

We installed a new master cylinder and clevis pin on a friend's '80 LE. We bled it until the engagement doesn't change no matter how long you pump the petal.

Any Ideas?

Bad CMC?

Bleeding the clutch can be a PITA. Some people have good luck and say its easy, others cry in their beer. I cried in my beer for awhile until someone mentioned "Gravity bleeding." I tried it (loosening the bleed nipple overnight is not too strenuous. Really, what was I going to screw up?) Forgot about checking it for a couple of days, tighten the nipple and I had a clutch.

Did you check the condition of slave, pin and push rod? Remove slave boot and examine for fluid.
I'm in the camp of "easy" clutch bleed.
You can try gravity (but not overnight 8-))
OR use a syringe and push bleed. Suck out master reservoir, Remove clevis pin from slave, compress piston gently, fill from bottom w/syringe until air bubbles into master reservoir.
Dont overfill!
RS

See how far the slave rod is moving. If it is moving two or more inches you may have a worn throw out "bearing". Or should I say throw out graphite pad.

Hey I forgot I'd done it. :) I was very surprised to have a clutch that worked after I did it.

Should be about .4 of an inch slave rod travel and pedal firm from top, almost top..

The slave is about a year old. I'll check the travel length but there seems to be quite a bit of slack at the top of travel. I'm thinking the T/O bearing is the culprit.

Does anyone sell an adjustable slave rod?

I think that you have air trapped at the top of the slave cylinder. This will cause what you have described. My clutch bleeding system involves unbolting the slave cylinder and compressing the piston with a C clamp. Try to keep the slave cylinder as high as possible while you bleed the system again. This usually purges the trapped air bubble from the slave cylinder returning your clutch operation to normal. RAY

when i changed all my parts last year i think i had to loosen the bleeder and use the release arm to push back towards the front of car to get the last of the air bubble out. did this 2 times and my clutch was perfect after. i fought it for hours and had a similar symptom that you had.

Thanks guys. I'll try another bleed.

Had this same problem about a month ago. Turned out, I DID have the hose and bleed screw reversed. Quick change, and that was it!! Check it out:

http://www.mgexperience.net/phorum/read.php?1,1939820,1939820#msg-1939820

You replaced the pin, but make sure there's no wear in the pushrod - it may be ovaled out.

I actually fit a slave off a miata on mine. Harder pedal but I'm used to it now.:)

I have a very similar situation in the shop right now.

The owner has spent about a zillion dollars on the car in just about every other area, and just as I was getting ready to turn it back to him this situation cropped up.

BTW, if you don't have a fluid leak at the slave it is working as it should.

I have dealt with clutch hydraulic countless times and I checked EVERYTHING external before deciding that the master was bypassing internally, no external leaks, so I replaced it with a new one.

That improved things but the release point is very close to the floor and I am not really happy about that.

The ONLY thing left to blame is a badly worn carbon in the release bearing, but I am reluctant to tell the owner that he is going to have to endure a clutchectomey after all he has been through already.

The car runs and drives like a dream otherwise, and if you remember to push the pedal completely to the floor, selection of reverse doesn't get the grinding, and selection of first is easy, but if you don't mash it completely, both problems rear their heads.

I guess that I am just going to grit my teeth and tell the guy like it is. :(

Jack

so, i dont see it in the post, but did you replace the clevis and pin in BOTH the slave and master?

I use the back pressure method:

Connect a hose to the left front caliper bleeder and to an slave bleeder screw; open the bleeders and then pump the brake pedal a few strokes. Then close all bleeders.Top up both masters accordingly. I generally bleed the front brake with a Easy Bleed to assure that the brake system is OK. The last time I had to do it twice because I had to change all the components (hose, master rebuild kit and slave kit)

You must also check the linkage for wear, push rod, clevis pin & the clutch pedal 5/16 hole. I had to weld and rebore the pedal hole because the wear was more that 2 diameter of the clevis pin. You lose a lot of slave travel with bad linkage.

Unfortunately, I am of the mind that once the carbon wears down to a certain point, it's too far gone and will simply wear faster. Mine went from good, and then push the pedal harder to the floor, and then practically no clutch at all. And the mess on the inside of the bell housing was a sight to behold. I was sure that I had a major seal leak until I discovered it was just melted carbon all over the place. (The PO gave this car to his 16 year old son to drive for 6 months. Can you say "don't ride the clutch?" As Jack said, if you eliminate an internal leak in the MC, the throwout bearing is where you are, like it or not.

Jack, I agree that you should just bite the bullet and tell the guy. Better that than down the road a ways, stuck on the side where ever with no clutch.

I did.

At least I sent him an email asking that we have a seance.

Jack

HAHA, Jack!!! The least you could do. There are many things you can put off until later. Unfortunately, clutch problems and brake problems can't be.

I have been doing a lot of work on a neighbor's car, and of course one thing cropped up after another. I actually advised him to sell it and get a Miata, because he is a real non-mechanical kind of guy and I know it's gonna be one of those deals that something is gonna happen every time he drives it.

Ovality of slave clevis hole and general wear in linkage is of no consequence as the clutch system is self adjusting.

Wear at the pedal end can cause not enough push on the master.

A really badly worn slave end could cause the pin to move within the worn hole and upset the adjustment, but it would have to be very bad.

The pressure plate always pushes back on the back side of the clevis/hole, so extra clearance at the front does not affect action.

John Twist has a recent video on clutch slave replacement and bleeding.

The bleed hole in the slave is not at the very top of the cylinder when mounted and will leave a little air in regardless. Take the cylinder loose from the transmission, let it hang and open the bleeder to get that last bit of air out, don't pump, just crack open bleeder. Bolt it back in and you should have a full pedal.

When you mentioned slave travel at 2 or more inches, I thought I better post a closer figure of about .4 inch so people won't go looking for those elusive inches.

Funny thing happened a cuppla years ago here.

Was a thread on slave travel and a dude here, (long time spat the dummy and left now), said it was 1/2 to 3/4 inch.

I ignored him and kept asking for a figure.

He got a bit pi$$ed with me asking again when HE ALREADY TOLD ME WHAT THE DISTANCE WAS.

Then I got got a bit pi$$ed and told him . I WANT A FIGURE USING A DIAL INDICATOR, NOT A DRESSMAKER'S TAPE........

Ha ha, he got real mad and sent me a PM that must have blown his blood pressure across the room. was real funny.

Anyway I never got an answer on anyone else's figure, so I checked mine with a dial indicator many times and I get .390 of an inch.

I will run with that figure until proven wrong or at least some comparative measurements to check with.

I believe the .39" is accurate. It sure doesn't take much.