So I was driving down the road the other day and the clutch started going out.

It would engage after quite a bit of clutch pedal travel and was getting worse. Like it had air in master cylinder.

I limped home, shifting without the clutch and with the clutch dragging at red lights.

Fortunately, no damage to the clutch disks etc.

I checked the fluid and topped it off. Either I didn't top it off after I bled the brakes last time, or it was disappearing somewhere. No drips, no puddling.

I let the car cool. And pumped the clutch a few times and got good engagement.

I figure I'll use the Jay K method of bleeding the clutch system - removing the piston from the inside of the car and topping off the fluid in the cylinder. When I do this, I get the Niagra Falls of brake fluid spilling out. I quickly reinsert the piston, and reassemble. Clean up my mess and top off the brake fluid. The clutch fells fine.

Take a drive around the neighborhood.

After about 10 minutes. I start to loose the clutch again. Same symptoms.

I get home. Check the fluid level - no change. Check for leaks, no leaks.

Let is sit for 1/2 hour. Pump the clutch, and I'm back in business.

I'm perplexed. Can anyone help?

Thanks....

 

Procedure is a major PITA but it sounds like you still have some air in there if no leaks. It took me 5 times to get it right and I think there is still room for improvement.

Stan has a great write up that helped me.

https://rennlist.com/forums/928-foru...acement-2.html
Post#17

 

Sounds like air but I have had a similar problem with brakes a while ago on my old Mustang and it turned out to be that I was boiling the brake fluid because of a line traveling too close to the exhaust header.Check to see that your lines are clear of the exhaust,check to make sure your rubber slave hose is solid and not expanding under heat and pressure,then flush out the hydraulic system with some fresh high temp brake fluid.Good luck, Ed

 

If it was air, it wouldn't work at all.

I'll check the lines near heat.

 

Have you recently replaced the intermediate plate? If so, you have to replace the friction discs as well. All of the newer IP's have a travel which is different from the original, so the updated discs are necessary for proper release. I had this issue and it would only manifest itself once the clutch got hot -- like you describe. Conversly, if you have the updated discs with the old IP you will have the same release issue.

Also, worn splines on the center shaft can cause release issues.

 

True, but if after some time the said air floats to the top and vents,you will have a good pedal until you suck it back in from where ever it is coming from.I also have read others having issues with the pushrod adjustment preload from the pedal to the master cylinder causing lack of engagement, although I haven't seen it myself.

 

Is the back of the carpet wet right behind the clutch pedal.

 

but my clutch pedal went to the floor with no resistance

 

nope. dry.

 

I'm pretty convinced I have a worn out, ballooning clutch line.

I am dreading the r&r

 

Note to self.....next time engine is out and on engine stand....



<----------------------------------------------


REPLACE THE CLUTCH LINES!!!!!!!!

I managed to get the clutch master all the way to the slave out as a system, threading it around everything and in such tight quarters (Thanks Sharkskin for documenting that it can be done).

I r&r the flexible line, bench bled the whole mess. And today told myself that I would get it back together.

Threading it all back to its general vacinity was not that bad. Few cuts here and there.

But what seems impossible, after a couple hours trying, was to get the clutch master back thru that firewall hole.

What a joke. You can't get your had in there to get any leverage. And the clutch line and the booster are in the way.

I was about ready to give up.

Then I managed to get my hand in around the brake lines from above.

Tried a severe angle kinda coming in from the center of the car.

Then with a good push, I heard what must be the best sound ever for the owner of a 5 speed old bugger - a mechanical pop as I somehow managed to force the master thru its hole in the firewall.

What you are about to see is a beautiful sight (well, it was to me).


The clutch master cylinder back in its natural habitat.

Quick drive around the block and she is shifting fine. Back in business!

 

Dan,

When I first saw your picture I thought "oh crap he broke the firewall" then I realized that was the broken insulation.

BTW when my blue hose went, it sprayed on the exhaust and fogged the town of Owasso for insects.

Dennis

 

Glad it worked out in the end, Dan... but you should have gone with the long bolts for getting it into final position!

 

If you have a helper to assist in the MC being moved into final position this part is very quick to complete, one person moves the MC from the outside of the car the other uses a Phillips screwdriver to move the push rod section into place then it drops in,
The plate and bolt spacers are installed while the MC is held in place

 

I've still got a problem.

When cold, I've got decent pedal. A little travel at the top and I have to push the pedal all the way in to disengage the clutch (no excess travel).

When it starts getting hotter, I start losing pedal.

This gradually starts after about 5 minutes where I can tell the clutch is not fully disengaged.

It then gets worse to were I only have an inch or so of pedal and I have to change gears with syncronizing rpm.

And finally, I have no pedal at all. It goes right down to the floor and stays there.

The car is still hot, I'll see if it "fixes" itself when it cools down.

Brake fluid is still topped off. No loss.

Brakes are working fine, maybe a bit mushy. But new and not bedded in yet.

What I've done is rebuilt the master and slave months ago. Bench bled. And all worked fine.

And then this happened.

I replaced the flex line (it was toast) and thought I was home free. I also wrapped the lines in reflective insulation wrap for added insurance against heat. The lines are routed in the stock location.

There is no leakage of brake fluid anywhere. Dry and tight.

I am going flush the brake fluid before I panic. The ATE super blue I have is a few years old. I'll get new.

I am worried that the master or slave is at fault, but I would think I would see leaking or a loss of brake fluid.

I was really on top of the world until this happened.

Please, any help is very much appreciated.