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Can't get my clutch to fully release... Pulled tranny, all parts look fine

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ajohncock Alex Johncock
Salt Lake City, Utah, USA   USA
So, as the title says, I cannot get my clutch to fully disengage. I've been able to make significant gains by "shimming" between the slave cylinder and the push rod. Even a shim of .600 inches though still hasn't allowed it to fully release.

In my frustration, I pulled the whole tranny out today hoping to find an obvious problem, but no. None of the pins or holes are overly warn, the release bearing is smooth and doesn't feel sloppy at all, the master and slave cylinder are both brand new and have been bleed 20+ times...

I'm at a loss for what could be causing it. I'm hoping you guys can see something in these pictures that I'm missing. Please save me from going down the path of fabricating some custom adjustable system for the push rod!

Pictures:










Edit: I was having about as much fun trying to make these pictures show up as I am getting this clutch working.



Edited 8 time(s). Last edit at 2017-09-24 08:19 PM by ajohncock.

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OFRacer Avatar
OFRacer Mike H
Poughkeepsie, NY, USA   USA
Hi Alex, I can't see the pictures but is there any chance the clutch disk was put in backwards? It should be marked but not all of them are. It burned me one time, in a rush to get the car back together.

mike h

ajohncock Alex Johncock
Salt Lake City, Utah, USA   USA
That's a good question. I'll have to look into it. Does anyone know if there's a way to tell without disassembling the clutch?

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Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, Nevada, USA   USA
In reply to # 1487742 by ajohncock Does anyone know if there's a way to tell without disassembling the clutch?

You mean besides the clutch refusing to release?

Tonyfixit Avatar
Tonyfixit Tony M
Duncan, British Columbia, Canada   CAN
I think I might have removed the slave and made a device to manually push on the push rod via a screw thread.
Then measure how far you need to depress it before the clutch releases.

Compare this measurment with the action of the slave cyl (jam a screwdriver down the hole 'hard' and depress the clutch pedal)

Adding shims will not alter the travel ( stroke) of the slave cyl piston.

Brad.Cogan Avatar
Brad.Cogan Bradley Cogan
RAF Cosford, Shropshire, UK   GBR
1977 Triumph Spitfire 1500 "Wray"
1989 Toyota MR2 "Red Mister Two"
2007 Fiat Grande Punto "Pepper"
Might be relevant, might not. Do you run DOT 5 fluid through it?



Brad Cogan

1977 Triumph Spitfire 1500 'Wray'
2007 Fiat Grande Punto Active 1.2 'Pepper'

ajohncock Alex Johncock
Salt Lake City, Utah, USA   USA
In reply to # 1487781 by Doug in Vegas
In reply to # 1487742 by ajohncock Does anyone know if there's a way to tell without disassembling the clutch?

You mean besides the clutch refusing to release?


I took the clutch off today to confirm that I had installed the disk the right direction, and it appears that I had. According to this thread, the side of the disk with the protruding spring plate should be facing toward the gear box and pressure plate. I was hoping this would be my fix, but it was installed correctly.

Any other suggestions?

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Tonyfixit Avatar
Tonyfixit Tony M
Duncan, British Columbia, Canada   CAN
If the clutch is OK, thenyou areback to looking for lost motion somewhere between the pedal and the throwout bearing.

I assume you have checked the pivot pin on the falcrum lever?

On the end of the clutch pedal is the linkage pin worn (if you lift the pedal, is there slack? )

Again, how much falcrum arm movment is required to disengage the clutch?

If you test the slave cyl (stroke) can it provide this movment?

Yellowhawk Valley Avatar
walla walla, washington, USA   USA
1969 Triumph Spitfire "Walla Walla"
1969 Triumph Spitfire "Portland"
1972 Triumph Spitfire MkIV "Spokane"
1975 Triumph Spitfire 1500 "Dayton"    & more
Have you lost the thrust bearings in the engine? Check crank shaft movement for and aft, Should be almost none. No idea what the movement might be with the loss but it will be noticeable. Check the history here to see info and stores about them.
Dan

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Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, Nevada, USA   USA
Look at the area around the pivot pin. Sometimes the arm has worn into an oval. Same goes for the top of the clutch pedal.

Also check out the fingers.

angel221 Avatar
angel221 Angel M
Cleveland, Ohio, USA   USA
Maybe a small burr inside the slave cyl? You won't get full travel as Tony wrote.
Ask me how i know this. LOL That was my problem after the clutch job and thrust bearing install.

Doug in Vegas Avatar
Doug in Vegas Douglas D
Las Vegas, Nevada, USA   USA
I'm posting this video again:


SpiTazz72 Avatar
SpiTazz72 Bryan H
Magnolia, Texas, USA   USA
Could it be the dreaded air bubble in the slave cylinder?

Smithisretired Avatar
Smithisretired Michael Smith
Wells, Maine, USA   USA
I will second Yellowhawk's suggestion that you check the crankshaft end float. I've posted this advice on other threads and even got to try it myself last week. The engine came out over the weekend -- thrust washers were worn.

ajohncock Alex Johncock
Salt Lake City, Utah, USA   USA
The engine was rebuilt recently with all new parts and has literally maybe 100 miles on it. I’ll check the thrust washers but I’m really hoping this isn’t an issue.

Believe it or not, I haven’t checked the pedal pivot... I’ll check that tonight.

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