Leaking wheel cylinder?

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Ohio66Cuda

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I replaced the power assist unit and the master cylinder in my 66 Barracuda last fall. When I tried to bleed the system, the last wheel cylinder (front drivers side) wouldn't bleed. I replaced the wheel cylinder with a new one and went through the bleeding procedure again. When I got to the replaced cylinder, I noticed braked fluid was leaking. I pulled of the wheel and drum but couldn't see where the leak was coming from. I had someone push on the brake pedal as I watched the cylinder but still couldn't see where the leak was. I pulled the new cylinder and inspected it but couldn't find any obvious flaws.
The only thing I could think of was the place where the hose screwed into the cylinder. The copper washer was present.
I thought I tightened everything down properly so what could the problem be?
Any thoughts or suggestions would be welcomed.
 
Copper can work harden and not seal. Either replace the copper washer with a new one or heat the defect free one you have to red and let it cool on its own and try again.

Did you peel back the boots and insure no fluid was leaking at either piston cap. Rebuilt wheel cylinder can have pitting and or have been honed oversized incorrectly. Lots of little things can go wrong and all it takes is one.
 
some times the replacement copper washers are too thin to seal right
 
Blind Squirrel said:
Copper can work harden and not seal. Either replace the copper washer with a new one or heat the defect free one you have to red and let it cool on its own and try again.

Did you peel back the boots and insure no fluid was leaking at either piston cap. Rebuilt wheel cylinder can have pitting and or have been honed oversized incorrectly. Lots of little things can go wrong and all it takes is one.
Click to expand...
Annealing copper is different than steel. You quench copper to anneal and let it cool naturally to temper it. Weird. I know.
 
Blind Squirrel said:
Copper can work harden and not seal. Either replace the copper washer with a new one or heat the defect free one you have to red and let it cool on its own and try again.

Did you peel back the boots and insure no fluid was leaking at either piston cap. Rebuilt wheel cylinder can have pitting and or have been honed oversized incorrectly. Lots of little things can go wrong and all it takes is one.
Click to expand...
Checked the piston caps on both ends and no fluid leaking there. I'm going with a new washer and make sure everything is clean during reassembly. I'll let you know how is goes.
 
Bodyperson said:
Annealing copper is different than steel. You quench copper to anneal and let it cool naturally to temper it. Weird. I know.
Click to expand...

Weird is right. In all my years I have never done it this way and never had a problem. Proves I'm never to old to learn. Thank you!!! :thumbsup:
 
Ohio66Cuda said:
Checked the piston caps on both ends and no fluid leaking there. I'm going with a new washer and make sure everything is clean during reassembly. I'll let you know how is goes.
Click to expand...
I wanted to close the loop on this problem and hopefully provide information to someone else who may have a similar problem. I did get a new washer and reassembled and bled the system. The leak still appeared in the same spot !!! So ... I went and bought another wheel cylinder and hose believing that the problem was with the poor quality of part I got with the Dorman brand. It looked to me like the finish on the port where the hose attaches was of poor quality. I bought some AC Delco brand parts. After installation of these parts and bleeding the system, I now have working brakes. Lesson learned.... don't be cheap when sourcing parts for your vintage vehicle.
 
Did you pull the dust boots on the wheel cylinder to see if there was brake fluid there? It's supposed to be dry.
 
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