Clutch/Slave Cylinder Problems

[utahmj]

Hey guys, I got a problem on my hands with my 1989 MJ 4.0 2WD with the BA10/5 transmission. To start at the first of my problems, my clutch pedal started to feel soggy. I checked the fluid level and it was low, so I topped it off. A week or so later it was soggy again and low so I topped it off again. Doing this over and over I decided to check the master cylinder. It didnt look like it was leaking too bad but it was a little bit, so I changed that out and bled it. After I bled it, it felt great, but then after only driving it around the block it went soggy to zero pressure and then there was fluid leaking between the dust pan and tranny. So I figured it was the slave cylinder all along. I then dropped the transmission and replaced the slave cylinder, while I was in there I replaced the clutch and pressure plate as well. Now with everything back together and after bleeding the clutch I get good pressure, but when I start the engine and try to put it in gear it will not allow me to at all, and the clutch pressure starts to slowly fade away. After shutting the engine off it seems like the clutch pressure gradually builds up again. I then bled it again and then pushed in the clutch while I’m gear and had another person try moving the truck. It will not budge. I can hear the clutch moving a little bit by repeatedly pressing the clutch with the engine off. I tried bleeding it several other times and still the same issue occurs. The tranny shifts perfectly while the engine is off and it has fresh fluid. I am stumped on this one guys... as of this moment I am going to try leaving the reservoir cap off over night while the clutch is pressed all the way down to see if any air in the system can work it’s way out. I would really appreciate any of your guys help as I am trying to get this going as soon as possible. Thanks.

[utahmj]

Sorry for the novel, I am just trying to be as detailed as possible, lol.

[eaglescout526]

I fight these issues from time to time. Its complete crap. I had to replace the master and slave on mine. I went through this issue. I knew the slave was bad as it leaked worse than a colander but I digress. I replaced the master and bled and bled and bled and still had craptastic shifting and played musical master cylinders till I got a crown cylinder and have been pleased with it. Then the slave finally gave up and swapped it in a new one. It generally is a good rule around here to replace the three components to the clutch system including the hose.

 

So far shifting for me has been good to me.

 

Also try starting the truck with it in first gear and pedal to the floor and see what happens.

[87MJTIM]

The seals on the master may be going bad.  When you press the pedal, fluid is leaking paste the seal and you lose pressure.  Purchase a new MC.

 

Or...

 

Look inside the cab where the MC come through the firewall.  Is it damp?  If so, feel the top of the fuse block.  Is it damp?  If so, the MC is leaking inside the cab.  Not good new.

 

Or...

 

The slave cyl you purchased is bad.  Not unheard of.  The would mean changing it out...again.

 

I got tired of changing slave cylinders (internal) so I swapped out trans to an external slave AX15 (94+).  You can purchase for a 2wd AX15 for probably not much $$,  Jeep owners are willing to part with a 2wd AX15 (94+) when they convert to 4wd.

[utahmj]

39 minutes ago, eaglescout526 said:

I fight these issues from time to time. Its complete crap. I had to replace the master and slave on mine. I went through this issue. I knew the slave was bad as it leaked worse than a colander but I digress. I replaced the master and bled and bled and bled and still had craptastic shifting and played musical master cylinders till I got a crown cylinder and have been pleased with it. Then the slave finally gave up and swapped it in a new one. It generally is a good rule around here to replace the three components to the clutch system including the hose.

 

So far shifting for me has been good to me.

 

Also try starting the truck with it in first gear and pedal to the floor and see what happens.

I believe my master cylinder is a Duralast brand. Are you saying the Crown brand or master cylinder is what worked for you? I did not replace the hose because it looked fairly good but due to the connection to the slave cylinder being rusty we could get disconnect it. So we ended up disconnecting it from the top of the master cylinder instead. To feed it down into the engine bay and to the ground we had to bend the living snot out of the brass hose. When I put it back on, I was somewhat able to bend it back to its original form but it is still deformed a little bit. I wonder if I should just replace it, but still I am not sure how that would be my issue if I am getting good pressure. 

I did try starting the truck in first gear, it would start just fine but will only turn the tire no matter if I press the clutch or not. 

[eaglescout526]

Yeah I currently have both crown slave and master and I'm pleased with them. I had a napa one after the factory master failed and it sucked. can't say the hose will always be the problem but it can. The flexible rubber end is so damn near close to the hot exhaust and engine that it can be a culprit.

[utahmj]

6 minutes ago, 87MJTIM said:

The seals on the master may be going bad.  When you press the pedal, fluid is leaking paste the seal and you lose pressure.  Purchase a new MC.

 

Or...

 

Look inside the cab where the MC come through the firewall.  Is it damp?  If so, feel the top of the fuse block.  Is it damp?  If so, the MC is leaking inside the cab.  Not good new.

 

Or...

 

The slave cyl you purchased is bad.  Not unheard of.  The would mean changing it out...again.

 

I got tired of changing slave cylinders (internal) so I swapped out trans to an external slave AX15 (94+).  You can purchase for a 2wd AX15 for probably not much $$,  Jeep owners are willing to part with a 2wd AX15 (94+) when they convert to 4wd.

The MC is new and is a Duralast brand also The slave cylinder is new and a Dorman brand. Have you heard of people specially having trouble with the Dorman brand failing? The reviews seemed good for the BA10/5.

I would love to do a tranny swap, unfortunately I am low on funds at the moment and my ZJ will need a tranny rebuild, which sadly may force me to sell the MJ, which is why I am trying to get it going as soon as possible. 

[utahmj]

13 minutes ago, eaglescout526 said:

Yeah I currently have both crown slave and master and I'm pleased with them. I had a napa one after the factory master failed and it sucked. can't say the hose will always be the problem but it can. The flexible rubber end is so damn near close to the hot exhaust and engine that it can be a culprit.

Do you by chance remember what brands did not work for you in the past? Currently I have a Duralast Master Cylinder and Dorman Slave Cylinder. Did you try either of those two? Also, where did you purchase the Crown MC and SC?

[eaglescout526]

I have not. I have only had the factory, napa and crown master. Lux brand clutch kits with slaves, which felt like a hit or miss for me and this current one is crown. I avoid dorman parts at all cost. They are the great value brand of auto parts. Course they do make that windshield wiper transmission bushing kit. 

 

But that's being said, All aftermarket parts are a hit or miss. Mopar or AMC is the way to go...but those parts have been long discontinued. So if these two brands aren't working out, then you may have to dump some money...

 

I just thought about this. Did you by any chance change the pilot bearing in the center of the flywheel?

[utahmj]

26 minutes ago, eaglescout526 said:

I have not. I have only had the factory, napa and crown master. Lux brand clutch kits with slaves, which felt like a hit or miss for me and this current one is crown. I avoid dorman parts at all cost. They are the great value brand of auto parts. Course they do make that windshield wiper transmission bushing kit. 

 

But that's being said, All aftermarket parts are a hit or miss. Mopar or AMC is the way to go...but those parts have been long discontinued. So if these two brands aren't working out, then you may have to dump some money...

 

I just thought about this. Did you by any chance change the pilot bearing in the center of the flywheel?

I did not. The clutch kit came with a new one, but the one that was in it seemed to be good, plus I did not have a bearing pulling tool. I decided to keep the one in it and greased it up a little bit.

[eaglescout526]

Ok good. If that pilot bearing isn't seated where it needs to be, the pressure plate can not push the clutch disk back enough to disengage.

[utahmj]

30 minutes ago, eaglescout526 said:

I have not. I have only had the factory, napa and crown master. Lux brand clutch kits with slaves, which felt like a hit or miss for me and this current one is crown. I avoid dorman parts at all cost. They are the great value brand of auto parts. Course they do make that windshield wiper transmission bushing kit. 

 

But that's being said, All aftermarket parts are a hit or miss. Mopar or AMC is the way to go...but those parts have been long discontinued. So if these two brands aren't working out, then you may have to dump some money...

 

I just thought about this. Did you by any chance change the pilot bearing in the center of the flywheel?

My apologies I thought it was a Dorman brand but I checked my order and it looks like it is actually a Southeast Clutch Brand.

[eaglescout526]

First I have heard of them. 

[utahmj]

6 minutes ago, eaglescout526 said:

Ok good. If that pilot bearing isn't seated where it needs to be, the pressure plate can not push the clutch disk back enough to disengage.

I see, are you saying that if I were to install the new one incorrectly and not seated correctly it would cause this? 

[eaglescout526]

Yup.....learned that one the hard way. And probably got the world record time for dropping an AX5 down.

[utahmj]

2 minutes ago, eaglescout526 said:

Yup.....learned that one the hard way. And probably got the world record time for dropping an AX5 down.

Man that would be rough... as far as I know the one in it was good so I said screw it lol. Is it possible that if the clutch was facing the wrong side it would cause my issue? I want to say that for sure I put it in the correct way because it had an indication on the clutch saying “flywheel side”. I want to say I put it in correctly but at this point I will consider any possibility and this is the first time I have ever done any of this stuff. I just wonder if it was facing the wrong way if it would cause these exact issues?

[utahmj]

59 minutes ago, utahmj said:

The MC is new and is a Duralast brand also The slave cylinder is new and a Dorman brand. Have you heard of people specially having trouble with the Dorman brand failing? The reviews seemed good for the BA10/5.

I would love to do a tranny swap, unfortunately I am low on funds at the moment and my ZJ will need a tranny rebuild, which sadly may force me to sell the MJ, which is why I am trying to get it going as soon as possible. 

I apologize I looked at my order and the slave cylinder is actually a Southeast Clutch brand.

[eaglescout526]

Yup. The clutch disk only pushes one way. If you are for sure certain you installed those components right, then I wouldn't worry about them and focus on why you are losing pressure in your system. 

[utahmj]

7 hours ago, eaglescout526 said:

Yup. The clutch disk only pushes one way. If you are for sure certain you installed those components right, then I wouldn't worry about them and focus on why you are losing pressure in your system. 

One thing I am really getting stumped about is as to why I am loosing pressure when the truck is running and I press in the clutch to get it in gear. The pressure should not change running or not running correct? When the truck is off it feels great. Then I start it and then after several times of pressing the clutch to get it in gear it goes soft, maybe not all of the pressure goes away but it does goes soft. Then when I turn it off and pump the clutch it builds up the pressure again. I also am not seeing any visual leaks anywhere and the fluid level is the same. One thing to mention is when I am bleeding it the truck is not level, would this trap any air? I figured it would get pushed out either way.

[eaglescout526]

That’s entirely possible. I’ve fought the same issue with the engine off great pressure and on no pressure. How does the bottom of the bell house look? Does it look like it has an oil leak that would be from the engine? 

 

[mjeff87]

When you put the new slave/throwout in, did you leave the little plastic straps on (and TO compressed)?  Those straps are designed to snap when you first engage the new clutch to bleed it.  If the straps weren't there, you might have accidentally pushed a bunch of air back through the system.

 

Also, it is possible that one (or both) of the hard lines that attach to the TO might have popped out after install.  Happened to me once, and I was not a happy camper.  Had to pull the tranny back off to figure out what happened, and I swapped out the cheezy little "U" clips that come with the kit with small cotter pins of the same diameter.  I bent the ends of the pins back around to make sure they wouldn't ever slip back out.

[utahmj]

3 hours ago, eaglescout526 said:

That’s entirely possible. I’ve fought the same issue with the engine off great pressure and on no pressure. How does the bottom of the bell house look? Does it look like it has an oil leak that would be from the engine? 

 

Between the bell housing and the dustpan/engine I do not see any leaks. This is where it was leaking before I removed the transmission because I assumed it was leaking from the Slave Cylinder. Now with the new one in, I do not see any leaks. Is this what your issue was when you had problems with different pressure when running and not running? 

[utahmj]

2 hours ago, mjeff87 said:

When you put the new slave/throwout in, did you leave the little plastic straps on (and TO compressed)?  Those straps are designed to snap when you first engage the new clutch to bleed it.  If the straps weren't there, you might have accidentally pushed a bunch of air back through the system.

 

Also, it is possible that one (or both) of the hard lines that attach to the TO might have popped out after install.  Happened to me once, and I was not a happy camper.  Had to pull the tranny back off to figure out what happened, and I swapped out the cheezy little "U" clips that come with the kit with small cotter pins of the same diameter.  I bent the ends of the pins back around to make sure they wouldn't ever slip back out.

Yes I made sure the Nylon straps were still on the Slave Cylinder keeping it compressed when I installed it.

 

When you say the hoses that attach to the TO that might have popped out, are you referring to the ones that run directly into the Slave Cylinder? 

[JustEmptyEveryPocket]

My first guess would be air in the system somewhere. I would recommend bleeding it until you are blue in the face, walk away, then rebleed it after a couple of hours.

[utahmj]

36 minutes ago, JustEmptyEveryPocket said:

My first guess would be air in the system somewhere. I would recommend bleeding it until you are blue in the face, walk away, then rebleed it after a couple of hours.

Yeah I will give bleeding the snot out of it a try, I compressed the clutch pedal all the way and left the reservoir cap off over night to see If it will force itself out. Also I have been lifting the truck up in the front with a jack for more room underneath the truck when I am bleeding it. Do I need to have the truck level when bleeding? Or does it not matter and it should force itself out no matter what?