Clutch not working when hot

[82DMC12]

Hey guys, since we are talking about clutch bleeding, here's one for you. I installed the DPI remote clutch bleeder which is a DOT hose that screws into the clutch slave and then runs down the bellhousing and attaches to a clip so you can operate the bleeder from under the car. Super slick. I installed it last fall. Today I went for a test drive after doing some work and almost immediately getting out of my garage I wasn't able to get out of first gear without turning the engine off. I backed back into the garage and got under it and found the bleeder on it must have been leaking a little bit because there was a drop of clutch fluid on the dust cover for it. My wife helped pump the clutch while I bled it from under the car and sure enough a bunch of bubbles came out on the first bleed. We flushed quite a bit to make sure it was OK and I closed the bleeder tighter this time. I asked her to push the clutch in and hold it one last time when I was done and as she held it to the floor, I could hear, from inside the clutch slave, a "tink tink tink" sound and I saw the piston and fork retract back into the slave about 1/4" and then seems to stop. When she lets go of the clutch, it retracts the rest of the way. I had her try this a few more times and I bled the clutch further but it still does that each time. I can't find any evidence of a leak on the slave or master, I have a SS line, and just today I had the air meter unit out and I looked at the new hose connection on the clutch slave and it is not leaking.

Anyway I did go for a drive after that and it was shifting fine....

That normal?

[WHO1DMC]

Hey guys, since we are talking about clutch bleeding, here's one for you. I installed the DPI remote clutch bleeder which is a DOT hose that screws into the clutch slave and then runs down the bellhousing and attaches to a clip so you can operate the bleeder from under the car. Super slick. I installed it last fall. Today I went for a test drive after doing some work and almost immediately getting out of my garage I wasn't able to get out of first gear without turning the engine off. I backed back into the garage and got under it and found the bleeder on it must have been leaking a little bit because there was a drop of clutch fluid on the dust cover for it. My wife helped pump the clutch while I bled it from under the car and sure enough a bunch of bubbles came out on the first bleed. We flushed quite a bit to make sure it was OK and I closed the bleeder tighter this time. I asked her to push the clutch in and hold it one last time when I was done and as she held it to the floor, I could hear, from inside the clutch slave, a "tink tink tink" sound and I saw the piston and fork retract back into the slave about 1/4" and then seems to stop. When she lets go of the clutch, it retracts the rest of the way. I had her try this a few more times and I bled the clutch further but it still does that each time. I can't find any evidence of a leak on the slave or master, I have a SS line, and just today I had the air meter unit out and I looked at the new hose connection on the clutch slave and it is not leaking.

Anyway I did go for a drive after that and it was shifting fine....

That normal?

That seems like a good reason not to have the habit of riding the clutch! I for one had this habit and had to break myself of it.



Dave B.

[David T]

When you step on the clutch pedal, inside the clutch master cylinder you are holding a valve closed to prevent the fluid from leaking back from the slave cylinder into the master cylinder. If that valve leaks the clutch will release even though you are holding the pedal to the floor. The fix is to rebuild or replace the clutch master cylinder. You will never see any leaks because it is internal.

[Helirich]

Hey guys, since we are talking about clutch bleeding, here's one for you. I installed the DPI remote clutch bleeder which is a DOT hose that screws into the clutch slave and then runs down the bellhousing and attaches to a clip so you can operate the bleeder from under the car. Super slick. I installed it last fall. Today I went for a test drive after doing some work and almost immediately getting out of my garage I wasn't able to get out of first gear without turning the engine off. I backed back into the garage and got under it and found the bleeder on it must have been leaking a little bit because there was a drop of clutch fluid on the dust cover for it. My wife helped pump the clutch while I bled it from under the car and sure enough a bunch of bubbles came out on the first bleed. We flushed quite a bit to make sure it was OK and I closed the bleeder tighter this time. I asked her to push the clutch in and hold it one last time when I was done and as she held it to the floor, I could hear, from inside the clutch slave, a "tink tink tink" sound and I saw the piston and fork retract back into the slave about 1/4" and then seems to stop. When she lets go of the clutch, it retracts the rest of the way. I had her try this a few more times and I bled the clutch further but it still does that each time. I can't find any evidence of a leak on the slave or master, I have a SS line, and just today I had the air meter unit out and I looked at the new hose connection on the clutch slave and it is not leaking.

Anyway I did go for a drive after that and it was shifting fine....

That normal?

I would think you still have air in the line. One thing I would do if I had the remote bleeder is have it higher than the slave while you bleed it. You want the air to go up and out. After you’re done, you can tie it down wherever.

[82DMC12]

I would think you still have air in the line. One thing I would do if I had the remote bleeder is have it higher than the slave while you bleed it. You want the air to go up and out. After you’re done, you can tie it down wherever.

That's an interesting suggestion, you might be right. I had the bleeder above the axle pointed pretty much horizontal but it was below the slave. I'll try to re-bleed with the hose unclipped and sticking up behind the engine. If that doesn't work, perhaps I need a new clutch master as David suggested. I have already replaced the slave and master once (Grady style) so I wouldn't think I need it again but who knows.

[Helirich]

I removed the bleeder and wrapped it generously with Teflon tape. Bled it again with the vacuum device. Still has bubbles, but less. Figured it was good and out everything away.

So I went to drive the car yesterday. No clutch. It was better before the Teflon. Got to thinking the vacuum thing can actually suck air past the cylinder seals because they only seal one way. If it did that, the air would be right in the cylinder. (As opposed to the line) It’s possible you could be sucking air in the master which means you would have to suck the whole system through to get that air out. At this point I don’t like the vacuum thing. I will be going back conventional bleeding.

Another thing I came up with. Might it be good to jack up or park the car on a down hill ramp to get the slave higher? That way air would be more likely to come back to the bleeder. Probably doesn’t make much difference, but easy enough to do.

[82DMC12]

I removed the bleeder and wrapped it generously with Teflon tape. Bled it again with the vacuum device. Still has bubbles, but less. Figured it was good and out everything away.

So I went to drive the car yesterday. No clutch. It was better before the Teflon. Got to thinking the vacuum thing can actually suck air past the cylinder seals because they only seal one way. If it did that, the air would be right in the cylinder. (As opposed to the line) It’s possible you could be sucking air in the master which means you would have to suck the whole system through to get that air out. At this point I don’t like the vacuum thing. I will be going back conventional bleeding.

Another thing I came up with. Might it be good to jack up or park the car on a down hill ramp to get the slave higher? That way air would be more likely to come back to the bleeder. Probably doesn’t make much difference, but easy enough to do.

Yeah I bought a MityVac for my brakes and I'm not impressed with it at all. I kept going around in circles bleeding over and over again and never could get a hard pedal. I ended up buying a Motive power bleeder and it worked so much better. For my clutch, I just grab the wife and have her pump while I bleed.

Later this week I will do another bleed because I think you are right, if I have the remote bleed hose pointing downward, any bubbles that remain in the hose are floating back up to the high point which is the clutch slave.

I don't use the mityvac for anything anymore except pulling a vacuum or sucking fluid out of something like the clutch reservoir or brake reservoir.

Sent from my Pixel 3a using Tapatalk

[Helirich]

Tonite I bled it one more time the old fashioned way. Actually, old and new. I still had the bleeder wrapped with Teflon. I just cracked it and put a hose on the bleeder to a plastic cup. I started pumping without a helper. The cup filled with fluid to the point where the hose end was under water. Then no air could get back in the hose. The Teflon seem to work to keep the air leaking past. I probably pumped a pint of new fluid through. I pulled the hose and tightened the bleeder.

I backed the car out of the garage. The clutch seemed to work fine. I wanted to take it for a short test drive, but the engine was running like total junk. I didn’t know what happened, but I had another project on the go and didn’t have time to investigate. I pulled the car back in the garage and worked on my truck. After I got that fixed, I wanted to take it for a test drive. The D was in the way, so I got back in and started it. Much to my amazement, it started right up and idled perfect. Drove just fine.

The truck test drive went fine and I pulled them both back in the garage for the nite. I figured I would quit on a positive note. I’m still baffled about engine, but I think the clutch is fixed.

I highly recommend the Teflon tape on the bleeder. I’m going to try that the next time I work on brakes too.

[82DMC12]

A couple nights ago I bled my clutch again, this time with the remove bleeder sticking up into the engine compartment. My wife pumped the clutch while I did the bleeding and it worked really well. I'm confident we got all the air out. Unfortunately within a day my clutch started acting up again. If I start the car in neutral and after warming up, shift into reverse, it goes into gear easily but as I'm slowly backing out of the driveway with the clutch in and feathering the brake, the clutch starts to drag and I'm fighting the brake. Once I get to the street, I can't get out of reverse unless I shut the engine off and shift into 1st, then restart with the clutch in. I went right back into the garage and inspected my hydraulics again. No leaks but inside the rubber boot of both the master and the slave it's a bit greasy/grimy but no standing fluid. I assume I'm suffering from the seal in the master cylinder is letting fluid backwards into the reservoir the clutch is in. This is causing the spring on the fork to retract and my clutch drags. Looks like I'm going to replace the master cylinder at minimum.

[Helirich]

Sorry to hear of your trouble 82DMC12. I took mine out for a test drive and I do believe my clutch is working good now. The car wasn’t running very good though. Almost seems like bad gas. Twice I could only get it started by holding the pedal to the floor. I don’t really understand that because, as I see it, the pedal doesn’t really do anything until the motor is running. I guess I need to study some more.