How do I bleed the AX15 or AX5 or AX4?

[gavin8or]

I looked around the forum and didn't find much in the way of tips/helps for getting a stubborn AX15 (EDIT: Ok turns out I need to bleed an AX5 but if anyone has done this with an AX15 or AX4, please chip in and help me out) to bleed. I want to get one done that full-time mechanics have tried and failed at. And my experiences with clutches have been limited to non-hydraulic motorcycle clutches which were fairly easy to fix.

 

I'm going to give it my best shot... if you guys can point me in the right direction with step-by-step howto or tips/tricks and pointers, please help.

[Pete M]

It'll be an AX-5, but the procedure for the internal slave cylinders is the same.

[jage]

The last time I bled my AX5 I was told or read or something that you have to both:

Start pushing the clutch in before opening the bleeder

and

Close the bleeder before the clutch petal bottoms out

 

Doing this didn't make any notable improvement on my clutch the first time, and the second time when I tried it to bleed the AX5 after reinstalling (empty hyd. lines) I wound up with a bottle of hyd. fluid on the floor of the garage and still no clutch. It's possible that this conventional method is what all the mechanics are trying, or something less effective even.

 

So, gist is, I don't think that method works. Then I called around to verify a part size, as different AX5 applications come with variations on throw out bearing and the one I removed was too long and the kit I replace with was opened and had other mismatched parts and found a comanche owner who also works the parts department at a Jeep dealer.

 

Here's how he said to do it- Specifically with an AX5...although I never got around to doing this myself yet (my project is shelved due to being 1800 miles away):

 

1. Remove the slave cylinder

2. Depress the push out rod on the slave keeping it compressed

(I was going to bolt a board across the front of the slave, or a strap of metal depending on how far out it was when depressed)

3. Bleed

4. Let the rod go an reinstall slave

 

Hope this helps, I wish I could back the second method up with personal experience.

[jage]

Rereading this I realized I need to step up getting my truck built so I can stop being a web wheeler. Oh man, I'm a web wheeler. Oh dear...

[gavin8or]

Thank you jage, I understand according to this method you don't need any new parts (other than the fluid).

 

That would be great if the mechanics working on this before simply weren't aware of the need to do that removal for the bleeding process. I could get this otherwise great truck back in the badass business!

[BIGMASS]

Any time a master cylinder of any sort runs dry it is a good idea to bench blead it. When I put the brake master in my manche the bench bleader kit concisted of plugs for the outlets. Just keep pumping on that sucker (on the bench) till air quits bubbling up (bout 25 clean pumps after the air stops).

[Oizarod115]

i installed a new clutch master cylinder on my truck, didn't mess with the slave though.

 

all i did was find the bleeder valve on the side of the bellhousing,

 

attach 1/4" dia. hose to end of valve, (don't remember the size but i used an open ended wrench to open/close valve.

 

run hose from valve into clean cup of brake fluid.

 

have one person in truck pumping pedal and one outside opening/shutting valve.

 

begin depressing pedal SLOWLY, then open valve, and wait til pedal is depressed, leaving it depressed close valve.

 

repeat. (end of hose should stay in fluid at all times)

 

this procedure can be found in your chiltons manual, thats where i got it from the first time.

[junior88mj]

i've had good luck useing a soda bottle and clear hose that gose to bottom and filled with an 1''of fluid this keeps it from sucking air back in connected to the bleeder with the bleeder open slowy pump the petal, have some one keep the master full of fluid i also bench bleed the master cylinder

[mjeff87]

and like the guys said, slowly depress/release the pedal. Do not pump the pedal (be it clutch or brakes). Pumping or quickly mashing on or releasing the pedal causes more air bubbles.

 

I bought a one man bleeder kit (from Harbor Freight, I think) that works great for the clutch jobs, but you can use most anything. Just make sure the end of the hose in the container is submerged and it doesn't draw air back up into whatever you're bleeding.

[Eagle]

Bleeding these things is a nuisance. I would strongly recommend using a Mighty-Vac, which is a little hand-held vacuum pump that pulls the fluid through from the bottom rather than trying to push it down from the master cylinder. It can be done the conventional way, though. As others have noted, it is critical to not just try to pump the peddle furiously. Press down, have helper underneath close valve, then let up. Put pressure on pedal, helper opens valve peddle goes down, helper closes valve. Let peddle up.

 

Two strokes is about all you get before you have to refill the master ... it doesn't hold much. Let it run dry even once and you introduce a big air bubble and you have to start over.

[xipantera31ix]

I bought the vacuum brake bleeder at harbor freight for $25, and bled all of my brake lines and clutch line with it. All you do is slightly loosen the bleeder screw, put enough fluid in to go over the hose, then pump it to about 25lb of vacuum, open the screw SLOWLY until the gauge begins to drop slow, and keep pumping it until you don't see any bubbles coming out of the tube, then tighten. You can't use it for ABS, but without ABS, it works perfect everytime. It is also alot easier if you wrap some teflon tape around the bleeder screw so that air can't leak through the threads. The manual method without the vac pump is easy too, the clutch can be done easily by yourself because you can push the clutch pedal and turn the bleeder with your hands. Just make sure that you pump slowly, hold it (the pedal) down about half way, open the bleeder slowly(watching for bubbles to stop) and close it before it bottoms out. I have never had trouble bleeding the clutch hydraulic system using this method. If this soesnt work, you probably have a leaky slave cylinder.

[gavin8or]

Here's how he said to do it- Specifically with an AX5...although I never got around to doing this myself yet (my project is shelved due to being 1800 miles away):

 

1. Remove the slave cylinder

2. Depress the push out rod on the slave keeping it compressed

(I was going to bolt a board across the front of the slave, or a strap of metal depending on how far out it was when depressed)

3. Bleed

4. Let the rod go an reinstall slave

 

Hope this helps, I wish I could back the second method up with personal experience.

 

Has anyone on here tried this, cause otherwise I won't try it. Jage, maybe the problem was that you didn't have a hose hooked up to the bleed valve and sitting in fluid?

[jage]

Theoretically the method I was using doesn't allow air to return into the bleeder valve- which is why you open and close only while the pedal is travelling. Of course it didn't work, so that's hardly supportive of anything.

 

And it's possible that there is a mechanical problem what with the mismatched parts and the different engine and all. If my buddy who I'm paying can't get it to work I'll be screwed because I really don't want to pay a mechanic to redo all the work I did.

 

But the other method came from a reliable comanche aficiando (he's on this board in fact) with lots of direct experience... but yeah, I never got around to trying it either. What do you have to lose? The clutch is already not working eh?

[Oizarod115]

But the other method came from a reliable comanche aficiando (he's on this board in fact) with lots of direct experience... but yeah, I never got around to trying it either. What do you have to lose? The clutch is already not working eh?

\

 

if you mean the method with removing the slave then you have alot to lose... dropping the tranny isnt a 5 minute job my friend.

 

or am i :chillin: and you're talkin bout another method?

[Guest johnnyhepp]

This system can be bled w/ only one (1) person, as it will gravity feed fluid right out the valve (bottom).

Raise the frount of truck (always use safety stands), remove cap off resivour, gently tap master cylinder to help any air escape from cylinder. (From underside of truck)

Crawl under and locate bleeder valve (passenger side of trans.), use a 1/4 inch wrench (socket at first if it's stubborn) crack open valve enough that it only drips slightly, use a hose method or large oil pan to catch fluid. Go back up and check the res. *make sure it don't go empty, you can stand there and drink a beer and watch the fluid level go down or reach in and depress your clutch petal slowly (3/4 way down max) if your impatient like me.ha ha. Refill res. about 3-4 times*(about 1/2 of a small container of brake fluid will do the job. Crawl under and close the valve,wipe up any mess, top up fluid, screw cap on the res. then check your petal, there should be good pressure & your clutch should now work!

[jage]

But the other method came from a reliable comanche aficiando (he's on this board in fact) with lots of direct experience... but yeah, I never got around to trying it either. What do you have to lose? The clutch is already not working eh?

\

 

if you mean the method with removing the slave then you have alot to lose... dropping the tranny isnt a 5 minute job my friend.

 

or am i :chillin: and you're talkin bout another method?

 

Or should I have remembered to mention that I'm talking about an EXTERNAL SLAVE? :dunce: Jeez, I totally forgot this might be an internal slave.

 

Sorry, yes there is a huuuge difference- the method I'm describing refers to the external slave. Not sure if it's applicable to the internal, I don't see why it wouldn't work, but you're right you'd have to be at your last last resort to try it with an internal.

[87manche]

the problem with gravity bleeding is that the bend in the tube that goes above the brake master traps air.

I delt with this when I had the hose burst and when I had to replace the master cylinder.

Take Eagles suggestion, get a vacuum bleeder by any means you can, it really is worth it's weight for bleeding the clutch system.

[Eagle]

Bleeding the XJ (and MJ) clutch is difficult enough that the factory clutch kits for the newer years include a complete (external) slave, master and hydraulic line, all preassembled, filled, and bled. You just install it and drive it.

 

Which suggests that perhaps an idea would be to disconnect both ends of the hydraulic line and force feed it fluid until it's filled, then connect it again. If you could also force feed the slave while the flex hose is disconnected from it, it might help "prime the pump."

 

When the hydraulic line blew on my XJ, I had no problem bleeding the system after replacing the hose. If this thing absolutely can't be bled, I keep thinking the master cylinder isn't working.

[gavin8or]

Raise the frount of truck (always use safety stands), remove cap off resivour, gently tap master cylinder to help any air escape from cylinder. (From underside of truck)

work!

 

How high do I have to raise it? I'm going to buy a hayes manual when I go into town tonight just to be sure. But how high did you block the front up when you did it?

[87manche]

Bleeding the XJ (and MJ) clutch is difficult enough that the factory clutch kits for the newer years include a complete (external) slave, master and hydraulic line, all preassembled, filled, and bled. You just install it and drive it.

 

Which suggests that perhaps an idea would be to disconnect both ends of the hydraulic line and force feed it fluid until it's filled, then connect it again. If you could also force feed the slave while the flex hose is disconnected from it, it might help "prime the pump."

 

When the hydraulic line blew on my XJ, I had no problem bleeding the system after replacing the hose. If this thing absolutely can't be bled, I keep thinking the master cylinder isn't working.

I thought that too Eagle, but it was a brand new bench bled master.

I just couldn't move the fluid fast enough through the hse to get te air to travel down and out the slave.

Harbor freight has a vacuum bleeding kit that's OK for $18. It's well worth it.