Clutch Master Cylinders Keep Bursting?

[rrack]

Ok. I'm helping my non-mechanical minded dad out with his work truck. He recently had a rebuilt transmission put in then the trouble just kept going...I think that it's a 1994 Chevy Cheyene 2500. It's a beast...4x4 with the granny gear & goose neck hitch in the bed...

 

Anyway, he had a hydraulic leak in the clutch line somewhere. I put a new slave cylinder and master cylinder. It worked for one week! The black plastic clutch master cylinder sprung a small hairline crack under the tank and just sprayed fluid all over the place until it bled down. I returned it and got another thinking it was a defect. It did the same exact thing a week after that. I returned that one to Autozone and asked for a cast metal one instead of the cheap/weak plastic. They didn't have one. UGH! I then went to another parts house and got another with a better warranty. However, it looked exactly the same...black plastic and made in the USA! This time it lasted one day and he broke down 50 miles from home without a clutch pedal! Ugh again! He managed to put a fourth one on and is scard to drive it now! They keep breaking in the exact place! right under the fluid tank on the bottom of the cylinder next to where the line connects.

 

I've cross referenced and there doesn't seem to be a heavy duty master cylinder for this truck or is there? Why do they keep cracking? Is it just our bad luck or are we being sold the wrong part? or could there be something wrong with his rebuilt transmission that he got? Or just a bunch of bad Master Cylinders floating around? I have no idea????

 

Any help or tips would be great!

 

Thanks,

Robert

[GMC_DUDE]

Well, as an automatic owner I'm not too familiar with the design, but I would say that after 4 master cylinders in a row, it's high time to look elsewhere for the problem. The cylinders are probably breaking because of excessive pressure. This might be caused by something in the clutch area jamming or dragging on the mechanism, requiring excessive force, and thus excessive pressure, to operate the clutch. I would have a look in that area: the slave cylinder, the release fork, the throwout bearing, etc., and see if something is amiss. Check the slave cylinder installation. Is it correct? Is the slave cylinder the proper size? Were all the adjustments made properly? Is there anything binding? Is there a kink in the hose/pipe? I think you'll find the answer somewhere there.

 

Peace and Coolness

 

GMC_DUDE

[99-2door]

My dad had a 94 K3500 Cab & chassis. It had the same plastic master cylinder. Never had any problems from it. Are you replacing the master cylinder and slave cylinder together as a unit? On his the hydraulic tube was not removable on either end. Sounds like you may have a problem in the clutch.