bump! :shocked: :grin:

 

That's why I don't like juice clutches.

The cups in the slave cylinder are usually knife edge cups, like a brake cylinder.
There has to be slight residual pressure in the lines to keep them sealed. Try putting a light return spring on the fork, to put a little pressure on the slave's cup.

 

I know better than to but I have to ask, how does a spring on the fork keep line pressure on the seal?

 

mmmm internal slave...

unless that changes nothing?

 

The same way a brake cylinder works. The spring keeps pressure on the cup (against the fluid, and drum brakes have a residual valve to keep slight pressure in the line,) keeping it flared out. As opposed to disc calipers - they use square O rings, they don't need something to keep them expanded.
No residual valve in the clutch, but gravity creates the little bit of residual pressure needed.

The clutch slaves have a weak internal spring - when it fails air gets in, just as the complaint says. The external spring pushes the fork, and thusly the piston, back enough.

Plus without the spring, the fork is still touching the fingers - no problem with that really (except for TO bearing wear,) but the vibration from it helps air get in too.

It's not the best cure, but it works - try it!

The right way - replace the slave - but that's alot of work!

 

No residual valve in the clutch, but gravity creates the little bit of residual pressure needed.

It'll do that with or without the spring.

The same way a brake cylinder works. The spring keeps pressure on the cup (against the fluid, and drum brakes have a residual valve to keep slight pressure in the line,) keeping it flared out.

The springs pull the shoes back against the stop post at the top. If not for the stop, the two cup seals would touch each other and cover the fluid inlet.

The right way - replace the slave - but that's alot of work!

Wouldn't be if it were an external, the kind with a fork you could put a spring on. I thought it was an internal from his picture.

 

TAZ, lets look at reality. If it was you that had the problem I would have laughed instead of answering. I would have waited for someone else to put up a 3 page dissertation of definitions.

What picture?

Yes, internal you can't get to it. I was thinking of external.

 

You not answering, had it been my problem, would have save me a trip for a spring and hoping that it worked.

You could have just said, “Oops”, but you tried to BS your way out.

I’ve never seen a Jeep with a hydraulic clutch but I have seen them on other vehicles. Owned a ’58 MGA with a hydraulic clutch. Best I remember, that MGA and the couple others I’ve seen had no adjustment. It depended on the cylinder not retracting more than necessary to provide the adjustment. If so on a Jeep, an added spring to retract the cylinder would keep the clutch out of adjustment.

 

So I need a new slave? I just put a new cluth and slave in august..

er I'm so confused now

 

Hard to tell what you need. It sounds like air is getting into the system somewhere.

You probably haven’t gotten any answers because you never asked a question.

Are you using any fluid? Can you see a place where the fluid is seeping out? Have you made any modifications?

You could have a leak in a hose or at a fitting. Could have a crack in a hard line. Could have a seal in a master or slave cylinder that just didn’t last long. You could have debris in the system that is causing seal failure.

I’m not knowledgeable on it but I suppose you could be using a fluid that is incompatible with the seals.

 

"""""I've never seen a Jeep with a hydraulic clutch but I have seen them on other vehicles."""""

Look around - Jeeps since WWII have used all sorts of clutch linkages - from purely mechanical rods to purely mechanical bellcranks, bellcranks with short cables - several versions - and even a long cable. None except the long cable were very good, they'd fall apart, come off, break - lots of trouble.
Probably at least 1/2 of the older Jeeps - 40's, 50's, 60's, early 70's etc - I've seen have been converted to juice clutches. I work on them all the time - not just the clutch either. There are several types and kits of juice systems available. Even a chain type! (Sounds good, but jams too easy.)

A heavy strong spring will pull it back too far, that's why I said a light spring - just enough to put pressure against the cup's lip and get it off the TO bearing.

But it's not only Jeeps that can benefit - ANY juice clutch needs the spring. Most slave cylinders have the light spring inside - go look at one!

PHX -
If you've already replaced the master and the slave, and there are no leaks - where do you think the air is getting in?

When you let the pedal up fast after depressing it - and you have a big spring on the pedal - the master can actually create a "suction" if it moves fast enough, faster than the slave cup moves. Remember there's also a return spring inside the Master.
If suction is created, the cup's edge collapses and sucks air in.
Try removing the big pedal spring as a test to see if that helps.

Remember too - air is much thinner than brake fluid - air can get through a place that brake fluid can't. Maybe loosen and re-tighten all the connections.
If it's under pressure (even slight pressure) all the time, air cannot get in.

All slave cylinders will suck a little air in. Make sure the line from the master to the slave are all downhill, no kinks, no loops or wows. Then any air that gets past the slave cups will float upward and come out the master. If there's any place where that air can collect, -- trouble.

Pretend you are a bubble and trace that line up.

 

"""""I've never seen a Jeep with a hydraulic clutch but I have seen them on other vehicles."""""

Yep, as soon as I posted that, I said Rich will show his ignorance and comment. You didn't disappoint me. You are SO predictable.

If you want to split hairs, I can have fun too. SHOW ME A JEEP WITH A HYDRAULIC CLUTCH (not torque converter). I know some have a HYDRAULIC CLUTCH RELEASE MECHANISM.

Yes, I'm sure I've seen a Jeep that had a hydraulic clutch release mechanism, in a parking lot, on a showroom floor, in a salvage yard, or on the street. I'm sure I've even ridden in one. I just never chased anybody down, pulled them over and asked if I could look at their clutch release mechanism.

When you let the pedal up fast after depressing it - and you have a big spring on the pedal - the master can actually create a "suction" if it moves fast enough, faster than the slave cup moves. Remember there's also a return spring inside the Master.
If suction is created, the cup's edge collapses and sucks air in.

Highly unlikely to be the problem.

... Then any air that gets past the slave cups will float upward and come out the master...

Yep, even if a little enters, it goes right out the inlet hole from the reservoir.

No need to send the guy on a snipe hunt.

 

Yup, as always, semantics - hydraulic clutch.

""""Yep, even if a little enters, it goes right out the inlet hole from the reservoir."""

So maybe you can explain a bubble that got in at the slave past the cup, can go out the "inlet hole" to the reservoir in the Master without traveling up the line? If the line isn't at a vertical slope, how does it float up?

THINK!

Now, since you obviously know so much about them because you've ridden in one, how do you think it's getting air in?

 

So maybe you can explain a bubble that got in at the slave ...

I'll post the quote for you again. YOU WERE TALKING ABOUT THE MASTER CYLINDER.

When you let the pedal up fast after depressing it - and you have a big spring on the pedal - the master can actually create a "suction" if it moves fast enough, faster than the slave cup moves. Remember there's also a return spring inside the Master.
If suction is created, the cup's edge collapses and sucks air in.

The second quote of yours is where you say that even from the slave it will go out the master reservoir. One that entered at the master goes out easy.

What is all this about a bubble not traveling up a line? You really need to do something about your lack of reading comprehension.

 

Obviously you aren't familiar with any juice clutch system. And obviously you must think a bubble doesn't travel upward.

Please give us a 7 page dissertation as to why you think a bubble travels downward, not up?

I've given a few suggestions as to where to LOOK not replace parts, no expenses involved, just taking a moment to LOOK and possibly loosen and re-tighten the connections.

And you, as always, have not offered ANY possible cause or solution.

Why are you bothering to answer - other than to prove yourself a ----.

Knowing somebody that rode in one doesn't qualify you as an expert either.

 

And you, as always, have not offered ANY possible cause or solution.

Again with your reading comprehension problem.

About 6 posts back.

Hard to tell what you need. It sounds like air is getting into the system somewhere.

You probably haven't gotten any answers because you never asked a question.

Are you using any fluid? Can you see a place where the fluid is seeping out? Have you made any modifications?

You could have a leak in a hose or at a fitting. Could have a crack in a hard line. Could have a seal in a master or slave cylinder that just didn't last long. You could have debris in the system that is causing seal failure.

I'm not knowledgeable on it but I suppose you could be using a fluid that is incompatible with the seals.

 

Ok well tonight after work im gonna do a complete run down on my line, and fittings, look for cracks, and the retighten everything

hopefully I find my problem

 

"""""Hard to tell what you need. It sounds like air is getting into the system somewhere.""""" Duh!
Post #1 he said he's getting air in the system. But it's good you cleared that up!

"""""You probably haven’t gotten any answers because you never asked a question.""""" Post #1 again -

""""Are you using any fluid?""""
I suppose that's something TAZ might do, try to operate it without fluid. It's hydraulic - meaning it uses fluid to operate!

"""""I’m not knowledgeable"""" Wow, finally a true statement!!

Sorry TAZ I'm putting you on ignore! I hate to do that since you have contributed some knowledgeable things here. I just can't remember what or when.

 

Sorry TAZ I'm putting you on ignore!

 

Master 0r Slave Could Be Bad

Had the clutch replaced on my Chevy 1/2 ton last year along with a new slave and mastercylinder. Turned out both new parts were bad and had to be repleaced.

 

Yeah I know the master is good, im on master replacement #3

slave, could be bad, thats my second one in there cause first one was bad.

 

Where you getting this junk? New or rebuilt?

 

the slave was apart of a clutch kit from Checker Auto the master was from pep boys... I don't like them anymore. I think the masters are rebuilt also.

 

I don't know exactly what's wrong, but strongly believe that either the slave or master is defective. My recomendation is to try to get your money back and then get new parts from NAPA.

It's theoretically possible for air to get in through a loose fitting or cracked line, but extremely unlikely if not impossible that it could do so without there being a copious fluid leak at that point.

And if you do get new components I would further recommend that you fill them with DOT 5 silicone fluid. I'm a firm believer in that stuff. I had it in my brake system for about twenty years without ever changing it, and when I did the restoration the entire system was completely free of internal corrosion and the rubber parts were like new. That's quite remarkable in a system that went wading frequently.

 

It's theoretically possible for air to get in through a loose fitting or cracked line, but extremely unlikely if not impossible that it could do so without there being a copious fluid leak at that point.

Jim - air is much much thinner than water, and even thinner than brake fluid. It's not uncommon for air to get in without a fluid leak. Brakes, clutches, lots of hydraulic systems. Anything where the pressure drops to, or below atmospheric.

Yeah, air is thinner than water, but with a max of 15 PSI to move it. The fluid is under much higher pressure.

OR he just didn't notice anything until the clutch wouldn't disengage properly, by that time the reservoir was empty and that was the source of the air.

 

Jim - air is much much thinner than water, and even thinner than brake fluid. It's not uncommon for air to get in without a fluid leak. Brakes, clutches, lots of hydraulic systems. Anything where the pressure drops to, or below atmospheric.

It could very well be defective parts, especially if rebuilt from a cheapie parts house.
But first loosen the fittings, tap tap them as you re-tighten them to "normalize" them.
It's alot of work to put ANOTHER slave in, try everything else first.

 

I'm going to tomorrow probably, and Jim about the dot 5... well it says to use dot 3 only so I don't know if I should... I don't know much about fluids though.

 

Yeah, air is thinner than water, but with a max of 15 PSI to move it. The fluid is under much higher pressure.

DOT 5 is kind of special stuff, several times as expensive as DOT 3, so the manufacturers don't think about mentioning it on the labels. If you're worried about it, call the rebuilder and ask what the problem is with DOT 5. You'll probably get a run-around instead of a straight answer, but I wouldn't worry about it. The silicone fluid is very benign stuff.

 

Yeah, that's possible, but one would think a leak that big would be obvious.

 

How big? We have no time frame. We could be talking months or even years.

 

In his first post he reported that he replaced the master cylinder "twice last week," so I would assume it isn't taking very long for the problem to recur.

 

We can assume he didn't just decide to replace the master cylinder for no particular reason. We can assume there was a problem before that.

We don't know why he replaced the master cylinder twice last week. I would assume he got a bad replacement or at least he thought he did.

It is common for people not to do a thorough job of bleeding after the master cylinder has been replaced. In this case, it was replaced twice. That could introduce a lot of air into the system that never got bled out. I don't know that what has happened since the master cylinder replacement is the same as the problem that existed before it was replaced. That spongy feeling is not as easy to detect in a hydraulic clutch system as it is in brakes so I don't know if he ever got all the air out.

The guy posted a problem but he didn't really ask a question. He bumped it back to the top and Rich tried to send him on snipe hunt making some bogus comment about putting a spring on the clutch fork.

I asked;

Are you using any fluid? Can you see a place where the fluid is seeping out? Have you made any modifications?

But I got no answers.

I think between you and Rich making ASSUMPTIONS, you have eliminated all possibilities other than witchcraft.

 

Yeah i bleed it when the pedal loses pressure for a temp fix that lasts a day or two