Clutch won't disengage after swap

[bubbagumper6]

Originally Posted by larry_g

I just put a clutch in mine and had an issue where I didn't have enough shim under the slave cylinder so it wasn't completely disengaging. The trans had to come out to ad a slightly thicker shim.

I have to ask the obvious, did you measure and adjust the gap according to the clutch manufacturer's specifications?

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I didnt measure/adjust anything. I guess i thought OEM replacement parts wouldnt need adjusting? The service manual didnt mention any adjustments either and i dont recall even seeing a shim.

[larry_g]

Stock ones generally don't need a shim but aftermarket clutches sometimes do. The clutch manufacturer will dictate what they expect for gap between the throwout bearing and pressure plate springs.

This is done through a series of measurements and calculating the gap. In my case, Monster provided an aluminum spacer and I still needed to add a shim.

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[RankSS]

If replacing with oem parts there is no need to shim.
You should have replaced the slave when you had it apart. I always recommend the billet bearing support and bleeder extension as well. Monster or Tick can fix you up.
Bleeding should be easy if all is well.

[bubbagumper6]

Originally Posted by RankSS

If replacing with oem parts there is no need to shim.
You should have replaced the slave when you had it apart. I always recommend the billet bearing support and bleeder extension as well. Monster or Tick can fix you up.
Bleeding should be easy if all is well.

I don't have a slave cylinder, the clutch draws from the brake master cylinder. I did replace the actuator cylinder (might also be called a throwout bearing? The cylinder that bolts inside the bell housing and actually pushes on the clutch fingers) it all came as part of the LUK kit. Bleeding on the V6 is easy, the bleeder valve is easily accessible with the car on jack stands.

[fz4k98]

I had this issue this spring after a clutch upgrade. My issue ended up being the clutch master cylinder under the dash was weak. It bled fine and had full pedal but would not fully release new clutch.

Swapped out my tick adjustable master cylinder for a new GM stock unit and problem was solved. I took apart the adjustable one and the pressure seal appears to be weak.

[larry_g]

The slave cylinder is what you are calling the actuator. The throwout bearing is on the end of the slave cylinder and is what actually makes contact with pressure plate fingers. The master cylinder is what the pedal pushes against and the reservoir is the fluid container.

If your clutch was supposed to be a direct OEM replacement, you probably shouldn't need a shim but I would definitely confirm with the manufacturer or supplier.

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[bubbagumper6]

Originally Posted by fz4k98

I had this issue this spring after a clutch upgrade. My issue ended up being the clutch master cylinder under the dash was weak. It bled fine and had full pedal but would not fully release new clutch.

Swapped out my tick adjustable master cylinder for a new GM stock unit and problem was solved. I took apart the adjustable one and the pressure seal appears to be weak.

I definitely considered this. I've had the car since it had 19k miles so i know the master cylinder and clutch were original. It seems to make sense to me that an old worn out master cylinder would still work with an old worn out clutch but not with a brand new stiff one, no?

Is there any way to diagnose a weak master cylinder? Replacement is only ~$60

Edit: Found this on another site:
"If the master clutch cylinder on a vehicle has gone bad, it will cause the fluid to rise in the reservoir when the clutch is pressed. To test this, watch the reservoir while another individual presses the clutch pedal. If the fluid level rises in the reservoir when the pedal is pressed and lowers when the pedal is released, the master clutch cylinder may need to be replaced."

I can absolutely see the fluid level in the master cylinder rise and fall with the clutch pedal.

Edit: Nevermind it looks like the fluid actually drops when the pedal is engaged and rises when released which would make sense.

[bubbagumper6]

Originally Posted by larry_g

The slave cylinder is what you are calling the actuator. The throwout bearing is on the end of the slave cylinder and is what actually makes contact with pressure plate fingers. The master cylinder is what the pedal pushes against and the reservoir is the fluid container.

If your clutch was supposed to be a direct OEM replacement, you probably shouldn't need a shim but I would definitely confirm with the manufacturer or supplier.

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I had always thought of a slave cylinder as being a dedicated cylinder just for a clutch, my last manual car had one.

This is everything that came in the kit and was replaced.

https://www.google.com/search?q=luk+...te=imgv&imgv=0

[larry_g]

The the part with the green plastic cover is the slave cylinder and the gray part on top of it is the throwout bearing. The way it is setup is slightly different than the SS but should function essentially the same. The bleeder setup is very different, I'd have to do some more research to see if there are any weird quirks with it.

That looks like a fairly complete kit but I would still confirm if they expect any measurements or shimming required.

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[bubbagumper6]

Originally Posted by larry_g

The the part with the green plastic cover is the slave cylinder and the gray part on top of it is the throwout bearing. The way it is setup is slightly different than the SS but should function essentially the same. The bleeder setup is very different, I'd have to do some more research to see if there are any weird quirks with it.

That looks like a fairly complete kit but I would still confirm if they expect any measurements or shimming required.

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Yeah i see now ive been screwing up a few names. What i was calling the master cylinder is just the resevoir. Woops.

Not sure where to go from here. Running out of energy to work on this thing. Thinking about either replacing the clutch master cylinder or just towing it to a shop. Supposed to go back to work next Monday so also running out of time...

Edit: Going to go ahead and order a new master cylinder. If that doesnt work I give up and she's headed to the shop...

[larry_g]

Good luck. Sorry I couldn't be more help.

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[bubbagumper6]

Originally Posted by larry_g

Good luck. Sorry I couldn't be more help.

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Thanks man, and you've been a lot of help. I appreciate it. I just may have gotten myself in a little over my head this time.

[bubbagumper6]

So the shop I took it to was pretty backed up and it sat for about 2 weeks before they could get to it. After tearing it back apart they immediately found the problem. Apparently I installed the friction disc backwards. *facepalm*

Now in my defense, I was following the diagram in the GM service manual which (in my mind) is actually incorrect. It shows/states the side of the disc where the center spline sticks out farther should face the transmission, which is how I installed it. Well you can also see on the old friction disc this is incorrect, evident by the clear "Flywheel Side" stamp that I clearly didn't notice...









I definitely blame myself for not noticing the stamp on the disc itself but am also pretty frustrated with the service manual inaccuracy. But at the end of the day the car is drivable again so time to move on. Hopefully this thread helps someone in the future not make the same mistake!