Drove the car all day, then it cooled down and i needed to bleed the clutch.

[Some guy]

Hey Guys

So i was drive the car for 4 hours doing running around. AC on and it worked fine. Then i park it in front of my place for a few hours. It cools down, and i go to start it and park it in the garage and the clutch petal just goes to the floor.

I tried bleeding it by having somone pump it. It didn't work. I had to use my soda cap with a bike pump attachment to pressure the fluid through the line. It worked and i got the car in the garage.

I don't know what to do to fix the problem. I have a 2 year old master and slave cylinder. the Line is braided. stainless.

I don't know if it is air in the line, or if there is a problem with my master cylinder not pulling in new fluid.

[Soundkillr]

Look for leaks, both inside the car, under the pedal and carpet, outside where the pedal goes in, and the rear above the transmission. One of them has most likely failed....

[Some guy]

I looked for leaks at lunch today, and it was dry.

Do you think a clogged reservoir cap could cause this? I was trying to blow through it and nothing.

[Chris 16409]

Did you check the in the driver's foot well around the peddles. You need to make sure there is no fluid leaking out of the front of the the clutch master.

[Some guy]

It is dry by the petals also. I replaced it 2 years ago because it leaked there.

from the master to the slave cylinder is completely dry.

I keep thinking there is a vacuum or a block in the master cylinder or the reserve tank.

Just to bleed it, i have to pressurize the reservoir tank.

[Ikeaboy1]

Check the mechanical linkage connecting the master to the pedal.

If it is in order, and you have no pedal feel or response at all, I'd suspect the master has failed.

[DMCMW Dave]

Make sure you have a tiny bit of freeplay at the pedal. If you have an adjustable linkage it is possible to have it so tight that it doesn't release the checkvalve (function), but the typical symptom of this is a slippy clutch.

Also - replace the plastic washer between the adapter fitting and the slave. Use a copper crush washer. I've seen them leak air in but no fluid out. Sounds impossible and honestly I didn't believe it until I saw it on a couple of cars.

[Some guy]

Thanks for the advice, i replaced the plastic washer last night with a new crush washer. I think there is enough play in the petal. It is not tight till you put pressure on it.

[Some guy]

Hi all

So yesterday was a hot day in the valley again and today after my car cooled down the clutch was soft to the touch. So i was reading some other posts and it seam that inside the master cylinder there is a rubber check valve that can go bad. It is like it is stuck closed. i can bleed the clutch by using a bike pump and forcing fluid through the system. This works till the system gets very hot. (90' day with ac on) Then the car cools down and the clutch is spongy.
The clutch has been just awful to bleed and it will not build pressure when pumping

There was also mention about the linkage. It seems ok, i dont see anywhere to adjust it. Is there something i should look for?



now this clutch has about 6000 miles on it and is 5 years old.

I am thinking about getting a rebuild kit and seeing for my self what is going on inside there.

[content22207_2]

It isn't a check valve per se -- it's a rubber tipped stopper that seals off the reservoir so that fluid is forced out to the slave cylinder rather than back into the reservoir. Tell tale sign of that stopper going bad is fluid shooting out the breather hole in the reservoir cap.

41594

Bill Robertson
#5939

[David T]

It isn't a check valve per se -- it's a rubber tipped stopper that seals off the reservoir so that fluid is forced out to the slave cylinder rather than back into the reservoir. Tell tale sign of that stopper going bad is fluid shooting out the breather hole in the reservoir cap.

41594

Bill Robertson
#5939

From the sounds of your problem the clutch itself is OK, there is a problem with the master cylinder or the slave cylinder. If the slave is not leaking and you have the S/S line the only thing left is the clutch master cylinder. Flush with fresh fluid and bleed well. If that doesn't fix the problem replace or rebuild the clutch master cylinder. If the hose between the reservoir and master cylinder is "sweating" replace it too.

[Bitsyncmaster]

It isn't a check valve per se -- it's a rubber tipped stopper that seals off the reservoir so that fluid is forced out to the slave cylinder rather than back into the reservoir. Tell tale sign of that stopper going bad is fluid shooting out the breather hole in the reservoir cap.

41594

Bill Robertson
#5939

I did the rebuild on my clutch master. Did that because I was seeing some leakage where the shaft to the pedal is. The rebuild seems to have fixed that.

Do you have the upgraded clutch line (hose)?

[Some guy]

I have the Stainless steal clutch line. the master and slave cylinder are only 5 and 4 years old.

i will try replacing the fluid, and see if that helps.

Is there any way the "check valve" in the master cylinder can be clogged?

[DMCMW Dave]

I have the Stainless steal clutch line. the master and slave cylinder are only 5 and 4 years old.

i will try replacing the fluid, and see if that helps.

Is there any way the "check valve" in the master cylinder can be clogged?

Any chance you have an adjustable link on the clutch pedal?

[Some guy]

I never adjusted the linkage on the clutch petal. it is an old car, so it could be done by the previous owner.

From what i can see, you press the petal down and the bar going into the master cylinder will go from a "loose fit" to finding the center on the plunger in side the master cylinder.

i am going to take off the rubber dust cover and see if the plunger resetting all the way back to the lock ring.

[content22207_2]

Again, the reservoir shutoff isn't really a valve -- it's a rod with a rubber tip:

41619

When you move the piston it presses against the reservoir inlet, sealing it off. The piston is hollow so it slides over the rod as it continues towards the back of the cylinder.

Bill Robertson
#5939

[Some guy]

So it happened again this weekend. I drove it, and the next day the clutch was limp.

I took the clutch master cylinder apart and cleaned it.

I think it was binding inside the sleeve and not coming all the way out. i had to slam it on a wood table to get the piston out.

So after inspecting it, it all looked good as new. Putting it back together I used lithium grease and it was still hard to push in. Once i added a little brake fluid to the rubber o rings, then it worked.

Now it is much smoother, and i am getting fluid pushed back in to the reservoir.(Just a little when the clutch is starting to be depressed)

[Some guy]

I just replaced the O ring by my slave cylinder. It was copper and i replaced it with a newer copper washer.

If this doesn't work, i was thinking about using DOT 5.1 break fluid.

My problem is when the car gets hot, so i was thinking it would be better to have brake fluid that can handle heat better.

[David T]

I just replaced the O ring by my slave cylinder. It was copper and i replaced it with a newer copper washer.

If this doesn't work, i was thinking about using DOT 5.1 break fluid.

My problem is when the car gets hot, so i was thinking it would be better to have brake fluid that can handle heat better.

Although DOT 5 may handle the heat better it is compressible because you cannot get all of the tiny air bubbles out of it so you would get a lousey pedal. Only guessing here but it sounds like the old fluid had some water in it and it boiled when it got hot. A flush and refill of fresh DOT 4 ought to cure it. Make sure the hose and piping for the clutch is not close to any exhaust pipes.

[Some guy]

So Again it happened today, i could not make it around the block before the DAM clutch lost pressure,or sucked air. I had the clutch feeling perfect cold, and as soon as it warms up. it just lost pressure.

I am going to remove the Special T Clutch Bleeder tonight, and see if that is my problem.

I am just hitting my head against the wall trying to find an issue with something that has all new parts.

[David T]

Any amount of air or moisture can cause this. Flush and rebleed. Make sure nothing is close to any exhaust piping.

[Some guy]

45106

So i bled the lines again. I checked to make sure the line was not touching the exhaust.

It was baffling me, so i looked at the linkage a second time.

I think these pins are bad. I just dont know if they are bad enough to make the clutch not work.

[refugeefromcalif]

45106

So i bled the lines again. I checked to make sure the line was not touching the exhaust.

It was baffling me, so i looked at the linkage a second time.

I think these pins are bad. I just dont know if they are bad enough to make the clutch not work.

Those are your problem. I had a similar issue and a new pin fixed it.

Here's (http://dmctalk.org/showthread.php?241-What-have-you-done-to-your-DeLorean-today&p=193561&viewfull=1#post193561) my post about it.

George

[Some guy]

Those are your problem. I had a similar issue and a new pin fixed it.

Here's (http://dmctalk.org/showthread.php?241-What-have-you-done-to-your-DeLorean-today&p=193561&viewfull=1#post193561) my post about it.

George


So the pins were bad, and i replaced them. That helped a lot.

but now the issue is back. I am going to replace the DOT4 Brake fluid. I am thinking there is contamination in there and that is causing me an issue.


What is the best clutch fluid to use?

Is there a flush or anything that can clean out all the old fluid?

[David T]

If you suspect the system is contaminated the best thing to do is disassemble, wash with alcohol, and reassemble. The recommenced fluid is Castrol DOT 4. If the bores of the cylinders are pitted, corroded, or rusty, they need to be replaced or sleeved. When reassembling it is always best to use new parts. There can be NO leaks allowed at all.

[Some guy]

When i was trying to bleed the clutch after replacing the fluid, i noticed my master cylinder was not releasing all the way. It was stopping about 1\2 inch from where it was suppose to.

So i took it apart and cleaned and inspected the rubber seals. The seals are about 2 years old, but still look great. The bore was like new, and very smooth. (Berry White smooth)

When i rebuilt it the first time, i used grease, then 2 years ago i used lithium grease and then this time i used the break fluid on the 2 plunger seals.


Did i do it right? What should i have used to lube up the master cylinder o rings?

I am just going to buy a new one if i have to do this again.

[hippieman9]

When i was trying to bleed the clutch after replacing the fluid, i noticed my master cylinder was not releasing all the way. It was stopping about 1\2 inch from where it was suppose to.

So i took it apart and cleaned and inspected the rubber seals. The seals are about 2 years old, but still look great. The bore was like new, and very smooth. (Berry White smooth)

When i rebuilt it the first time, i used grease, then 2 years ago i used lithium grease and then this time i used the break fluid on the 2 plunger seals.


Did i do it right? What should i have used to lube up the master cylinder o rings?

I am just going to buy a new one if i have to do this again.

Its recommended to lube the part you are rebuilding or installing with the fluid it uses. If you are rebuilding a caliper or master cylinder, use DOT 4 fluid as the lube. It is recommended to use Castrol GMA Dot 4 (now in a black bottle). use the same fluid in the clutch and brake systems.

[Some guy]

Its recommended to lube the part you are rebuilding or installing with the fluid it uses. If you are rebuilding a caliper or master cylinder, use DOT 4 fluid as the lube. It is recommended to use Castrol GMA Dot 4 (now in a black bottle). use the same fluid in the clutch and brake systems.


Thank you, this is exactly what i did!!! i am high fiveing my self lol