I was having a little bit of an issue lately with shifting into 2nd on my 96 4.0 ax15. It would intermittently have a mini-grind going in, and occasionally just refuse. This would usually involve going back to neutral, release the clutch, then back on to try again. I changed the gear oil for some Redline MT90 as it seemed to be a well respected option. This helped a bit, but not completely. I also had another perceived issue where my pedal seemed to have too much slop in it.

https://www.cherokeeforum.com/f2/clu...estion-254180/

It was a replacement MC from the previous owner, pretty new. The pushrod was non-adjustable (as are all of the stock replacements I’ve seen). I had about an 1-1.5” of slop before there was any resistance. Shifts to second required full, to the floor pedal travel. It was weird because the clutch didn’t seem to grab until you reached the top of the travel, but you still had to really depress it to shift cleanly.

I was originally going to try to modify the stock pushrod to make it adjustable, but then I read a post on another forum about using a Wilwood MC (260-15098), which has a threaded pushrod already. Bolt spacing is the same, bolts right up. The problem lies in attaching to the pedals as I couldn’t find any 5/16”-24 threaded eyelets for the pedal end. I ended up using a 1” “thumb screw” (90181A605 from McMaster), drilling it out, welding on a washer for extra beef, and attaching it with a coupling nut (90264A450) and some lock nuts. Thumb screw was a little long so I cut about a ¼” off. I have seen 5/16-24 "clevis" pushrod ends. If I did this again I'd probably start with one of those, smoosh it in the vise, and drill that out...

Good a time as any to replace the slave and the hydraulic line. I got a ⅜-24 to -3AN adapter for the MC side, a 48” braided -3AN brake hose, and an adapter from Advance Adapters (ADD-716130TJ), -3AN to “roll pin” for the slave side. Slave was a new one from Centric (CEB-139-67007), which I chose because it was metal and showed a bleeder valve on it from the picture on Rock Auto. Of course, there is no bleeder valve. Oh well. I also used 2 90* -3AN fittings, 1 one on the MC, one on the slave. They were unnecessary. If I did it again, I’d leave off the one on the MC as it got in the way. The one on the slave was slightly helpful, but really you need to make a 180*. 48” was plenty without too much extra slack.

Results: Mixed. Pedal feel is MUCH firmer. I think the stock MC bore is 11/16” (.6875), and this is .75”. I used this MC because I read how it had been used by other Jeepers with success. If I did it again, I’d go with the .70”. I wish I had done a bit more research there. Honestly, I’d even consider trying the ⅝” bore to get that smooth, linear feel to the pedal. Right now, it all kind of happens in that first inch or two.
But…
Shifts to second and overall are smoother, and I no longer have much pedal slop (I left a tiny bit on purpose). So it is a victory, or at least progress. Hope this helps somebody.

I'll try to get some better pictures later.

 

A few more pics.

 

Quick update.

I got fed up with the super stiff pedal with the .75 bore MC. I got the same master in a 5/8 bore (# 260-15096), and it is sooooooo much nicer. Bolts right in, used my same eyelet that I made before. Much lighter, but not "too" light. Just right, and it still has enough displacement to disengage the clutch easily.

 

Great job on that, and nice write up.
Thanks for the part numbers.

 

I wanted to give this thread another quick update in case someone else ever decides to do something similar. I just recently did a clutch job on my 96. The old clutch started slipping. I had thought it was the original, but it must not have been, Valeo brand. As far as I can tell, Luk would have been original. I reinstalled the standard Luk kit. That pressure plate had a MUCH lighter feel. I had no trouble installing the slave cylinder by hand, pressing against it. With the old one, it was a bear.

Anyway, getting to where this thread is relevant, I was getting a bit of a clunk, grind, and resistance to shifting. I re-installed the .75 bore master, and it's good to go. A bit firmer pedal, but I'd rather be able to shift. So, if I were to do it all over again, I'd get the .70 bore MC.

 

Thank you for this. I m glad you came back and updated this thread. I am about to pull the trigger on a wilwood unit. I keep getting leaky oem-like replacments from the parts stores. Mine has been on 3 months and drips from the back of the rod into the cabin. Others will leak past the seal internally and let air in. Im hoping the Wilwood is superior in quality.

 

I know it somewhat of an old thread but do you think the .75 bore or the 5/8 bore would be better for a stage 1 pressure plate ? Got a ****ty situation going on where the oem MC system isn't strong enough to push the prongs in the pressure plate and can't disengage the clutch.

 

You don't have to do anything with the slave cylinder right ? That could just be oem ?

 

When I did this, I used a stock slave cylinder, just used the fittings mentioned above to get everything plumbed.

As far as bore, if your current stock MC isn't pushing enough fluid, and that is .70 bore, then .75 would probably be the way to go. Just be warned that you might end up with a much stiffer pedal. A smaller bore (.70 or 5/8) might work if they had more travel than stock. I haven't investigated that. Right now I'm back to stock Luk pressure plate and clutch, and using the .70 Wilwood MC. I've tried all three sizes! Once you modify the eyelet part of the pushrod, it is relatively easy to swap them out. I like to bleed the system on the bench, then install the slave and master as a unit.

Good luck.