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Resolved Extend master clutch rod or shim pivot ball

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AWD-Tony

Proven Member
6,801
3,733
Sep 11, 2017
Cincinnati, Ohio
So I recently had a clutch disc failure where it came apart from the rivet. I put a new disc, new pp and changed to a used light weight flywheel which I had the machine shop resurface along with .610 step height. I also shimmed the new pivot ball and changed to used forged clutch fork.

After reinstalling, it engaged right off the floor. I adjusted the master rod as far as possible and adjusted the top clutch switch so it can push as much fluid as possible. This did help raise the engagement point and is drivable now.

The position of the clutch fork in the window is dead center and when the clutch is pressed in all the way, it really isn't close to the edge of the window in the trans.

I've read all the threads and watched Jack Transmission's video. I did the drag test at 7k rpms and it does engauge.

Master and slave are about a year old from Oriellys and worked fine before.

Should I try a 2g master rod or do I need to shim the pivot ball with a thicker washer?

Thanks
Tony

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How's the master cylinder? Sounds like it's not moving enough fluid Tony.
 
How's the master cylinder? Sounds like it's not moving enough fluid Tony.

The master is new, about a year old, from Orielly's. To me it doesn't seem like the master is pushing the slave far enough. I'll have to check again tomorrow how far it pushes the slave. Wondering if the 2g rod for the ms will fix this issue.
 
I saw you were searching for one and I'm not sure. Most say that is a band aid for what is really wrong but it seems to work for some.
Just a thought, is your rubber line (the old dam thing that comes from the hard line to the next hard line) in good shape, not ballooning out and transferring all the fluid as it's supposed to? I never trusted that line and when the stick car is back up and running I will put a SS line from master to slave so i don't worry about it. I have had a couple cars that had problems with the front brake rubber lines. They both broke down on the inside and allowed fluid to go through but not return. That is the only reason I ask about that old rubber line in your case.
 
I'll have to check my pedal assembly but I don't think that's the case since it was fine before.

I saw you were searching for one and I'm not sure. Most say that is a band aid for what is really wrong but it seems to work for some.
Just a thought, is your rubber line (the old dam thing that comes from the hard line to the next hard line) in good shape, not ballooning out and transferring all the fluid as it's supposed to? I never trusted that line and when the stick car is back up and running I will put a SS line from master to slave so i don't worry about it. I have had a couple cars that had problems with the front brake rubber lines. They both broke down on the inside and allowed fluid to go through but not return. That is the only reason I ask about that old rubber line in your case.

It's steel braided line also. Also changed the slave when I replaced the master.
 
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Ok then that is out of the picture. Sure seems as if the correct amount of fluid isn't getting to the slave, as it would move the finger more and you wouldn't be experiencing drag.
 
Yeah I'll take a picture of the fork with the clutch pushed in all the way. After I installed everything, it would engage right off the floor. I adjusted the master rod as much as I can, mind you there was't much left on the threads, and that did raise the engagement point so it's more drivable. I adjusted the upper clutch switch as well and that raised it a little more, but still having drag issue at 7k.

The golden rule has always been: use OEM master and slave. You'll usually be fine once you switch them out. Then maybe a bigger turbo..

LOL maybe later for the turbski.

New OEM, IDK about that. It was fine before I changed everything.

The golden rule has always been: use OEM master and slave. You'll usually be fine once you switch them out. Then maybe a bigger turbo..

Can you even get new oem master and slave?

I don't think it's the pedal assembly. The master rod moves as soon as there's pressure applied to the clutch. Zero free play.
 
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There are 2 versions of slave cylinders. One has a smaller bore/piston than the other, which translates to more or less movement at the slave. If you've got the larger of the two, you can increase travel by using the smaller version.

https://www.dsmtuners.com/threads/gstwithpsi-galant-vr4-1837-of-2000.482807/page-17#post-153750177

You can try an extended rod, just make sure you're not overextending the PP fingers. In extreme cases, you can cause them to hit the clutch disc.

If you've already shimmed the pivot, I assume something is awry. With a shimmed pivot, it shouldn't take much to get the proper travel on the fork at that point.

Did you verify the step height on the flywheel, to take the machine shop's word for it?
 
From what I remember, after putting everything back together, I do recall the slave not traveling anywhere near the edge of the window. I’ll take a pic tomorrow and post it. I did order a 2g master to swap the rod which should be here Wednesday.

I did check the step height before install.
 
There are 2 versions of slave cylinders. One has a smaller bore/piston than the other, which translates to more or less movement at the slave. If you've got the larger of the two, you can increase travel by using the smaller version.

https://www.dsmtuners.com/threads/gstwithpsi-galant-vr4-1837-of-2000.482807/page-17#post-153750177

You can try an extended rod, just make sure you're not overextending the PP fingers. In extreme cases, you can cause them to hit the clutch disc.

If you've already shimmed the pivot, I assume something is awry. With a shimmed pivot, it shouldn't take much to get the proper travel on the fork at that point.

Did you verify the step height on the flywheel, to take the machine shop's word for it?

Where or how can you order a slave with the smaller piston?
 
Are you sure its been bled completely?

I didn’t open the system. I used a small socket to cover slave piston and a heavy duty zip lock bag and zip tied the slave. Not a drop of fluid was in the bag
 
Slave cylinders are tricky, the air ends up trapped and the bleed point is clear at the bottom of the system at the slave, the whole time air wants to rise to the top of the system to the master cylinder where it cant be bled, using a power bleeder makes it easier, I hook up the power bleeder to the slave then pull a vacuum and then crack the bleeder open and using your hand push the slave piston all the way into the cylinder, this eliminates air behind the piston hiding, do this a couple of times even, then lock down the bleeder while still pulling vacuum on the system, then go inside and pump it a few times and then go back out and power bleed the crap out of it, this time leaving the master piston alone.
 
Just bleed it and it grabs at the same point. Didn’t do the drag test. Here is where the fork sits when clutch is fully depressed. There’s about 1/4 inch from making contact

You must be logged in to view this image or video.
 
I used FaceTime to view the movement between pedal and slave. There’s zero extra play in the pedal assembly. Also checked this inside when I was adjusting the master rod so I can definitively rule out the pedal assembly.

If the longer master rod doesn’t fix this, I will try the slave @GST with PSI mentioned
 
I dont mean to be captain obvious here but the only things pertaining to this issue that changed are the clutch disc, pressure plate and flywheel right?

I see that step height was checked but where you able to compare the old flywheel step height to the new, carefully and accurately?

Any difference?

You most likely have already heard that you should never need an extended pushrod to solve an issue like this.


^^^Edit: looks like we where typing at the same time^^^
 
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I had this problem just last week. I swapped to a fidanza flywheel/ACT clutch setup. I bled everything but I could only get 3/8" of slave and the clutch would barely disengage right at the floor. Neither the slave or master were leaking, but they appeared to be original units so probably very old. I tried and extended slave rod which i didn't expect to fix anything and it didn't. It just moved the piston a little further into the slave but I still had the same travel distance.

With the master cylilnder rod adjusted all the way out, the pedal was pretty mushy until I got about 1/2 way to the floor. The pedal assembly had no flex either. So I wanted to try the 2g master rod shown here https://www.dsmtuners.com/threads/master-cylinder-rod-adjustment-fix.462232/ but instead of buying the $45 master cylinder I just grabbed a bolt at the local hardware store and took the end to the bench grinder. Once I installed that longer bolt I was able to get solid pedal pressure immediately upon pushing on the clutch pedal and the clutch disengaged perfectly. I haven't measured the slave rod travel distance, but its disengaging/engaging great now. Also, I pushed on the fork and I'm able to push the slave rod into the slave so I'm not blocking off the self adjusting feature of the master cylinder. I wanted to try this $2 fix before I followed everyones advice about spending hundreds of dollars on new oem master/slave cylinders.
 
I'm curious about this. If the hydraulics are free to self adjust then it is not physically possible to gain travel by moving a piston. For all those reading consider this. How about an air bubble at the slave?Would it react differently if it were in the slave vs in the small line?
This reply isn't meant to dispute what you are seeing. It's meant to understand why. Everything I know about hydraulics and physics says what you're seeing isn't possible. There needs to be something else to help explain. Would you agree?
 
You want to shim it more with a head bolt washer and adjust the throw so you don’t have to much if you have to much it can break the clutch plate.

The extended slave rods don’t do anything and are 100% useless. See my post here for checking if shiming will help or not while the trans is still in the car.

Jack from Jacks trans had it right 12 years ago when he posted a video of how to shim the pivot ball.

https://www.dsmtuners.com/threads/shim-pivot-ball-while-still-in-car.422935/page-2
 
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