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YJ Clutch Question

6K views 38 replies 10 participants last post by  sudsytimmy 
#1 ·
Hello all, any advice is much appreciated!

I have a 94 YJ Sahara 4.0 5 speed.

When I press the clutch pedal down, it lets me shift gears etc.

However, if I hold the clutch pedal down, it slowly "lets out", meaning, if I'm in first gear with the clutch pressed down, during the course of around one minute the jeep will engage in gear.

Feels like some kind of vacuum issue or something like that, but I'm not familiar with vacuum systems.

Can anyone point me in a direction to see if I can fix this?

Again, thank you all in advance!

Tim
 
#2 ·
Clutch

Sorry, not vacuum. Either the clutch master cylinder or slave valve is leaking. Are you loosing any clutch fluid? If so you have found the leak that needs repair. If no leak is found then either the master or slave could have an internal bypass leak and needs repair.
 
#3 ·
X2 on what Andy said. Its most likely the slave cylinder that has an internal leak and is letting the fluid bypass which allows the clutch to "bleed off" and engage.

If it were the master cylinder, then you wouldn't normally build any pressure in the first place. So I would go with the slave needing replaced.
 
#4 ·
Thanks a lot, very helpful!

I've never done these particular jobs before, so it is now time to do research!

It's not my dd, and it's been like this for about a year now, so I'm not too urgent about it. I want to do a lot of research so I can minimize mistakes.

From preliminary research, it looks like if I get the master and slave cylinder kit, there is no need to bleed, but again, I must do research.

Thank you!
 
#7 ·
It does look like I am lucky to have that external slave. Knock on wood, it looks like a pretty straightforward repair. I'll get around to it before it gets cold out. It's been like that for over a year now, and doesn't seem to be getting much worse, but it would be nice to actually fix it.

Thanks again everyone, much appreciated!
 
#10 ·
Some external slaves are bleedable I done it on my brothers 95 I was not seeing things it is possible there was a small allen set screw on it bleed it worked fine he had same problem you are haveing and fixed it right up so you may want to look it over see if you also have that screw good luck
 
#11 ·
Thanks tyler. I'm just getting back from a trip, so the plan is to have a look at everything, I don't honestly even know if it's low on brake fluid or what.

I'm wondering too if the stuff that leaks out of the Jeep is hydraulic fluid. I had always thought it was oil, but who knows? Could be a leak in the master / slave.

Thanks for the info; I'm going to check into it soon.

Tim
 
#12 ·
Got out there the other night, and I'm full of brake fluid in the master cylinder. I'll just replace the MC and SC as the pre-bled kit.

The only question I have is, how does the slave work? In other words, it looks like you just insert it into the tranny, but does it hook on to anything in there? Or does it push something in there, so you basically just bolt it on?

The rest looks straightforward enough ...
 
#13 ·
It doesn't hook on to anything, just bolt it in, if you get the pre bled combo, do not remove the plastic retaining strap first, bolt the whole thing in and the first time you push the clutch that will break the plastic and allow you to use your clutch, don't ask me what happens with the plastic, but it didn't hurt anything.
 
#22 ·
Take the slave off of the bell housing, and lay it on the ground. Stretch the line out as straight as possible.(I ran mine out from under the jeep to the driver's side so that I could keep an eye on it) Fill the reservoir with brake fluid (DOT3 or DOT4). Open the bleeder valve on the slave and then get in the jeep and give the clutch pedal short pumps, about 1" of pedal travel. keep a close eye on the level of the fluid in the reservoir. Watch for when the fluid starts to come out of the bleeder. If you can get a steady stream of fluid out of the bleeder by doing that, no other bleeding should be necessary. If not then you will need to bleed it once it is installed in the Jeep. But that takes 2 people. Its just like bleeding the brakes, pump the pedal, hold pressure on the pedal about half way down, crack open the bleeder till the pedal goes to the floor, tighten the bleeder, release the pedal and repeat.

If you can start the Jeep in neutral, and push the clutch pedal in and engage 1st gear without grinding, then it is bled good enough. If not, repeat the bleeding process until it does.
 
#23 ·
I'm pretty sure there is no bleeder on the slave; it's the Crown part.

I read in another post to pump the slave about 20 times, refill MC, pump again.

Saw this procedure on Quadratech too, so I'll be trying that soon.

I thought I had ordered the pre-bled part, but I guess not.

Let's see how this goes!
 
#24 ·
Bled the MC / Slave by doing this:

Removed the slave from the tranny.

Pushed in the slave so I could feed the plastic straps out through the bolt holes.

Allowed the slave to extend all the way.

Poured new brake fluid into the reservoir

Pump the slave more than 10 times.

Refill MC with brake fluid.

Pump more than 10 times.

Refill MC with brake fluid.

Pump MC about 10 more times.

During the pumping you can "feel" whether or not there are bubbles left in the system. Keep the slave close to the ground (I pushed the pin in ON the ground, so I knew I was low to let air bubbles out). Once pumped a few rounds, you can tell that there isn't any air left in the system.

Push in slave and reattach plastic clips.

Top off fluid in MC.

Bolt slave back on transmission.

The way I did it, then I lost the cotter pin holding the MC onto the clutch pedal. So in my case, then you have to go to home depot and get a bunch of cotter pins, put one on the clutch pedal, and voila:

Done!

Thanks everyone so much; this totally fixed the clutch problem I was having and while it wasn't 15 minutes, at least it was completed same-day!
 
#27 ·
Excuse me for jumping in on this thread, I'm new to forums and such and don't know if I should post a new question. But Sudsytimmy's clutch problem sounds very much like mine. I have a '95 4.0L YJ with over 273,000 miles. In Feb. I finally had to replace the original clutch at 265,000 miles. Three months later, it happened twice that it got stuck in reverse gear when I backed out onto the road. Co-workers and friends suggested that it was a transmission issue. So at 270,000 miles I had the tranny rebuilt (it was getting rattly anway). Since then, it sometimes sticks in 1st gear. It doesn't happen a lot, but it shouldn't happen at all, right? It tends to happen when I'm inching along in traffic or crawling through a busy parking lot, and feathering the clutch pedal a lot. The shifter gets stuck so hard I can't even wiggle it, I have the clutch pedal to the floor (and the brake, too) but it's still trying to pull forward. If I'm able to go forward, when I barely let up on the clutch and brake, the Jeep will jump forward. If I cannot go forward (like I've just pulled into a parking space), I have to take my foot off the clutch pedal (which only comes up a little bit) and stall-out the engine. The clutch pedal will stay down and the shifter will stay stuck until I turn the key off. Then the shifter pops loose and the pedal slowly comes up. Is this being caused by a faulty master or slave cylinder, like Sudsytimmy's was? I really would appreciate some help diagnosing this. Thanks.
Deb
 
#28 ·
Deb, that is EXACTLY what was happening to me, and replacing the master and slave cylinders TOTALLY fixed the problem. The parts cost me around 135, and if I had known to bleed the system as described in the thread, the total time would have been around 45 minutes to complete the job.

Like Pmryall says, don't put it off, this will COMPLETELY fix your problem.

Good luck,

Tim
 
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