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Clutch won't disengage. Slave snapped in two.

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syndr0me

10+ Year Contributor
147
27
Oct 19, 2011
Pincourt, QC_Canada
6 bolt swapped

I bought a used fidenza 6 bolt, new valeo street disc and reused my old ACT 2600 PP. new flywheel bolts. torque with an electric impact rated to a little over 110ft/lbs. not ideal but its all i had and gave the bolts a good hammering.

I bleed my clutch line. Fork had a good 3/4 inch movement when clutch pedal pressed in.

When the engine is running, I can not make it go into any gear. I adjusted my clutch rod quite a bit. Still not disengaging.

So i decided to start my car in first gear. It starts and dosnt move. Ok, good news-ish.. I slowly let go of the clutch and it grabs almost right away. Ok, not so good, but makes sense given current situation. I push my clucth pedal all the way in, and decide to give it some revs. I get to 3500rpm and BAM. car jerks forward like i just dumped the clutch ans stalls. Pedal won't come back.

I take a look under the car, and my slave cylinder casting snapped in half where it bolts to the tranny.

Why is my clutch not disengaging? and why did my slave exert such a force on the fork that it made it snap?

Are my flywheel bolts not torqued enough causing my clutch assembly to "float"?

Used flywheel would mean if anything, that the step height would be to deep and I would have the reverse problem, correct?

Did I install my clutch disc on backwards?

Is this valeo stock replacement disc to thick?

 
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Just dealt with this a couple months back myself when I was installing my South Bend clutch. There was another member having a similar problem with his clutch not disengaging too. He had a Fidanza, but a different PP and disc. Both of us had 6 bolts but they were in 1gs, so maybe things are a tad different on your end. I'm not sure.
I'll still share everything in case it helps in some way.

I'll give you my story really quick. Mine turned out to be the clutch master cylinder. It was bolted too tightly to the firewall and the rod either wasn't getting a full throw or was binding when the pedal was pressed. It also caused issues with bleeding. Similar symptoms to what you described, but I never snapped the slave. Car would go into gear fine when off, but once I turned it on, I was locked out of everything.

So I would check and recheck that hydraulic system. Look at lines, bleed, double-check bolt torque.

1. Are my flywheel bolts not torqued enough causing my clutch assembly to "float"?

2. Used flywheel would mean if anything, that the step height would be to deep and I would have the reverse problem, correct?

3. Did I install my clutch disc on backwards?

4. Is this valeo stock replacement disc to thick?

1. According to the published torque specs for a 6-bolt, the flywheel should be 94-101 ft.lbs. Making 110, over torqued.

2. You need to measure this with a depth mic; see my message below.

3. I had this thought during my install. In my case, when I popped everything apart and tried to flip the clutch disk around to see if it was backwards, it wouldn't bolt back together without forcing it. So this probably isn't likely.

4. You would need to look up the specs of that clutch setup and then measure it to see.

Btw: what master and slave cylinder are you using? Are they real Mitsubishi products or parts store brands?

I know you have to replace the slave, and you may have already checked these things, but just in case....
-In 1gs, the pedal assembly itself expires. There are bushings in the bracket where the pedal pivots that wear out. Maybe it's different in a 2g.
-Check to see where the fork sits in the little window under the trans. When everything is at rest it should sit in the middle or a bit towards the driver side of the vehicle.
-Verify the fork and pivot ball are in spec. They may look alright to the naked eye but using a caliper you can check this for sure. Exact specs are listed here in the forums.
-Bleed the system using the methods listed on the forums. Make sure to press in the slave by hand to push out that last bit of air that can hide there.
-Flywheel step-height has to be within spec and measured with a depth mic. From what I've read, it differs between setups (figure out what that clutch setup specs are). But 0.608-0.612" is what you're shooting for.
-Are the pressure plate bolts torqued to the proper spec or torqued at all?
- Was the clutch centered with a clutch centering tool when installed? Did the clutch get misaligned during trans install?

That list contains some common problems I've read about and dealt with myself during DSM clutch/trans nightmares. I swapped my transmission in and out three times by myself during the above mentioned South Bend fiasco. If I can do anything to help another DSMer avoid a similar scenario, I will!

Hopefully one of the clutch and trans experts will weigh in here soon.
 
Btw: what master and slave cylinder are you using? Are they real Mitsubishi products or parts store brands? not a clue, didnt replace them

I know you have to replace the slave, and you may have already checked these things, but just in case....
-In 1gs, the pedal assembly itself expires. There are bushings in the bracket where the pedal pivots that wear out. Maybe it's different in a 2g. pedal assembly is tight
-Check to see where the fork sits in the little window under the trans. When everything is at rest it should sit in the middle or a bit towards the driver side of the vehicle. it seems to rest in the middle... hard to tell exact. ill verify tmr
-Verify the fork and pivot ball are in spec. They may look alright to the naked eye but using a caliper you can check this for sure. Exact specs are listed here in the forums. can't. its f***ing cold out. i do everything on the street
-Bleed the system using the methods listed on the forums. Make sure to press in the slave by hand to push out that last bit of air that can hide there. bleeded that b*tch thorougly, i hate sloppy pedals. pedal was really nice and stiff. really anal about brake and clutch pedal stiffness
-Flywheel step-height has to be within spec and measured with a depth mic. From what I've read, it differs between setups (figure out what that clutch setup specs are). But 0.608-0.612" is what you're shooting for. Can't tell you. It was a used fidenza. If anything i assumed a larger step height if anything
-Are the pressure plate bolts torqued to the proper spec or torqued at all? to spec? no. really tight? yes
- Was the clutch centered with a clutch centering tool when installed? Did the clutch get misaligned during trans install? I eye balled it. and it slipped on the first try.

I'm really leaning towards a a friction disk that is to fat, or to shallow of a step height (which to me, would make not sense. the fidenza def had some good miles on it.)

Below is an attachment is the clutch parts i used. I doubt it will help with anything, but there it is.


**EDIT**

I'm noticing the new friction disc has 3 smaller springs. I'm starting to wonder if this disc is even the right one... I bought it from a 4g63 speedshop about an hour from where i live. Surprise surprise, a month later, the shop and website no longer exist. I think i got duped. he also sold me the flywheel as well...
 

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Dhan,
I'll give you my story really quick. Mine turned out to be the clutch master cylinder. It was bolted too tightly to the firewall and the rod either wasn't getting a full throw or was binding when the pedal was pressed. It also caused issues with bleeding. Similar symptoms to what you described, but I never snapped the slave. Car would go into gear fine when off, but once I turned it on, I was locked out of everything.
.....
Dhan, this is the second time in the last 6 months I've read about someone dealing with a clutch master cylinder that was bolted too tight to the firewall. I've also read about at least one person welding a plate to the firewall's master cylinder mounting surface to stiffen the area. My thoughts or question is, how would someone even come to realize this as being a problem?(clutch master cylinder mounted too tightly)
 
I'm really leaning towards a a friction disk that is to fat, or to shallow of a step height (which to me, would make not sense. the fidenza def had some good miles on it.)

Below is an attachment is the clutch parts i used. I doubt it will help with anything, but there it is.

I'm noticing the new friction disc has 3 smaller springs. I'm starting to wonder if this disc is even the right one... I bought it from a 4g63 speedshop about an hour from where i live. Surprise surprise, a month later, the shop and website no longer exist. I think i got duped. he also sold me the flywheel as well...

It's hard to tell from the photo but if it's out of spec in regards to the step height, there will be disengagement issues or possible slipping. Those Fidanza flywheels come with removable friction surfaces, it could be well worn.

If your hydraulics are tight and operating as they should the only way to verify the rest of the system is working is to tear it apart again. I'm sure you don't want to hear that, but that's the only way to measure step height also. Especially since you're working on the street. I've been there when I lived in an apartment and did everything in the parking lot. Not fun.

I'm curious to see that broken slave. Do you have a photo of that?

My question is, how would someone even come to realize this as being a problem?(clutch master cylinder mounted too tightly)

I figured it out by accident. I told this story in a PM but I'll post it here just in case it helps someone....

Back when I was having the issue, I had my buddy over and we were messing with the car. This was after I'd swapped the trans three times, bought a new fork, pivot ball, slave, and master. I had been working on it over some time and was very frustrated at this point.
Anyway, he was on the forums on his phone and found the 2g master cylinder rod swap for 1gs (which allows more throw than the 1g master cylinder rod). I told him I read about it and it's just a band-aid.
Regardless, we decided to give it a shot and went over to the local O'Reillys. Got back, swapped the rods, bled the system, and fired things up. It worked! Could shift into all the gears, putt around the driveway, no grinding. Perfection.

Strange thing though, this new 2g rod wasn't adjusted out all that far yet (we planned to adjust it out in increments and use the Jacks method where you press the slave in with your thumb). Then we noticed we'd forgotten to tighten down the master cylinder to the firewall. The bolts were finger tight.
This was a yellow flag for me. At this point, I knew the car well. I decided to switch back to the original 1g rod.
Fast forward a few minutes. This time when we bolt the master to the firewall, we're careful and go by what the FSM says. Just the minimum: 7 ft/lbs.
Sure enough, it works great again. Just for fun, we tightened the two master cylinder bolts more to see if we could see anything strange happen.
We couldn't see anything with the naked eye, but soon after it gets tightened, the clutch fails to disengage. We had to loosen the master cylinder bolts to get the clutch working again.
The only thing I can think of, is that the firewall is warped from age or a minor accident. On a related note, other parts have never aligned quite right on this car. A lot of hings have needed filing and tweaking to bolt back together. The battery tray, one of the radiator brackets, the front bump stop, etc.

Anyway, we put the master cylinder bolts to 8 ft/lbs and that was that. Functioned as it should and still does.
 
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Thanks for the explanation Dan, hopefully it does help someone out. I'm curious to see a pic of that broken slave as well.
 
I know thisis from months ago, but it's good info regarding the issue I've had since last summer. I had a leaking master cylinder, so I replaced it with one from O'Reilly's. Not the greatest solution, but figured it would at least work. I had nothingbut grinding problems and could never get the pedal adjusted properly. So a few months later, I bought a rebuild kit for the oem one I kept (I rarely throw away bad oem parts). Sadly, I had the same problem, and to this day I still have it. The system worked perfect prior to all this so I have been firm in believing it's a problem with the master cylinder and pedal being iut of adjustment. I have however looked to see if the fork is in the proper spot and so forth. Nothing has worked. In the next few weeks I'll be dropping in a fresh engine along with the awd trans and other parts. I currentlyhave a Fidanza flywheel installed that I bought new. Last January, I replaced the clutch disc with an old one I had in storage, that I also had since new, since my wife was learning to drive manual and didn't want to ruin a new disc. I didn't have my alignment tool with me for some reason, but I did manage to get everything installed, and it worked good until the master cylinder issue later in the year. Could that be a possible reason for my clutch problems now?

The flywheel going in for the awd swap is also a Fidanza part that came with the parts car, but I have since replaced the friction surface and the step height is good on it. I will be getting a new clutch disc for it, and make sure I got my alignment tool as well. Any ideas?
 
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