Clutch Cylinders keep failing

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Had some time to mess with it again. With the pedal adjusted so it won't over extend and push the piston out I can't engage the clutch. I threaded the yoke out 1-2 turns and can now release the clutch but the piston sticks out of the bore again. Not sure if this is normal.

I really don't know why I can't get this to a point where the clutch works without the slave failing

New Video
 
Ok so is the slave rod perpendicular to the clutch fork as in straight in - max movement of clutch fork for the movement of the slave rod - if the angle is off then you will be wasting clutch pedal movement. How much play in the fork - there should some or your throw out bearing runs all the time. Next is where on the fork arm is slave rod connecting - some forks have two positions pick the inner one, modify fork to have an inner position - make sure slave rod points straight in - the slave bracket will likely need some modifications.

You can test my concept by wiring/welding a big nut to the fork closer to the bell housing.

Yes see if you can push the slave piston back in farther the rod disconnected from the fork.
 
The angle is pretty wonky due to the bracket. If I had access to a welder I'd fix it. There are two positions on the clutch arm and I am using the outer one..I thought the outer position provided more throw. I'll move it and see what I get. Clutch fork is adjusted so the TO bearing is just barely off of the clutch fingers

Appreciate all the replies
 
The inner one does more throw. And my pedal hits the floor.
I’ve never looked under the rubber boot to see what mine is doing. I too would build a new mounting bracket straighter and also use a longer pushrod. Unbolt it and move it back and using just the one bolt to hold the slave in place see if it looks different adjust angle and use a longer rod If it looks good figure out a way to mount it with the two bolts. If it’s the cheap AA flimsy mounting bracket just bolt a piece of flat stock to it and drill new holes in the flat stock and move it farther away and make a new longer pushrod. Hmm. That angle and short rod is probably side loading the piston causing the rubber cup to fail.
 
Here is what has been working on my junk. The bracket does flex a bit. Using Inner hole on the fork and mine doesn’t line up that good either but I’ve been using it like this for 20 years
,
IMG_7193.webp
 
Last edited:
I used an old slave cylinder and marked new holes in the bracket that correct the geometry. I can confirm the pushrod is centered enough to not drag on the bore anymore. Since the new holes are lower I flipped the slave so that the bleeder is in the correct position as well. I moved the pushrod to the inner position of the push arm. Everything is bled and at least working enough to rock it back and forth in the garage.

The piston still comes out of the bore about 1/8 to 1/4 of an inch, not sure how right or wrong that is.
 
badsamaritan said:
The piston still comes out of the bore about 1/8 to 1/4 of an inch, not sure how right or wrong that is.
Click to expand...
That does not sound right, is the slave retracted all the way into it's cylinder at rest? Open the bleeder and see if you can push it in further
 
Bleed nipple is now on top

@Pighead I pushed the piston until it bottomed out and then used the clutch, it went right back to coming out of the bore slightly. Only thing I can think of is that I have a mismatch in bore sizes between the MC and the slave?
 
badsamaritan said:
Only thing I can think of is that I have a mismatch in bore sizes between the MC and the slave?
Click to expand...
Is possible. Another difference between 3 and 4 speed clutches? Are the cylinder bores and strokes listed in the FSM?
 
Pighead said:
Is possible. Another difference between 3 and 4 speed clutches? Are the cylinder bores and strokes listed in the FSM?
Click to expand...
I'm running a SM420 mated to a 5.3 LS. Everything is about 6mo old. And from AA. New flywheel clutch pressure plate. The bell is a 56 Corvette bell. Fork Arm is the GM straight arm
 
I think you are correct. Your master and slave are not compatible with each other. The master pushes more fluid than the slave can handle. The other possibility is the piston is not fully retracting completely In the bore, which would indicate the return spring is not strong enuff. You can check and see, after depressing the pedal and releasing it then push on the slave rod and see if the piston is fully seated in the bottom of the bore. I don't believe its an adjustment problem.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom