1940 ford wheel cylinder leakage? Defects?

Ok, I have 1952 Olds rear out back(stock), a wilwood single jar, and 1940 ford brakes out front(stock). I have a residule valve straight out of the master cylinder. I went to bleed my brakes and as soon as the brake fluid fills the lines, the front start leaking.The rear wheel cylinders are holding. I pulled the front cylinders off and noticed there may be an imperfection on the seals. I get new cylinders from from Vintage ford and they do the same thing.I pull them apart and there is no noticeable flaws. Any suggestions? Maybe I missed a step?

Thanks,
Sean

 

Are your cylinders leaking from the piston dust cap area or at the line connection?

 

Adjust the shoes out with the adjuster cams on the sides and the bottom BEFORE you put fluid into the cylinder. If the springs are pulling the shoes too far inward, it will push the rubber cups past the fluid inlet hole and the fluid will leak out the boot.

I experienced this myself.

 

Are the wheel cylinders new or used? If use, you might have to run a wheel cylinder hone through the bore to clean them up.

 

Yes ,adjust first as this can happen. Me 2

 

Its the seal leaking not the line connection. Both sets are new. Only thing i can think is there remanufactured, and something was done wrong. However, I may have had them in too much i'll try to put them out more.

 

This is a common problem with people that have a habit of playing "squeeze me" with the wheel cylinders before assembly. Your cylinders are leaking because you have dislodged the seat of the internal puck seal. Squeezing the pucks in and out during assembly will do the same thing as playing with the pistons before assembly. All you have to do is carefully disassemble the wheel cylinder and reassemble it so the piston seal is square in the bore of the wheel cylinder and reinstall the cylinder.

Remove rubber dust cover, remove piston, remove piston seal, remove seal spring, coat cylinder bore with light coat of brake fluid and re assemble just like you took it a part.. Repeat operation on opposing side bore. Remember only install piston to a depth to be flush with the edge of the wheel cylinder. Clean up any brake fluid residue before installing and you should be good to go.

 

Good Advice and solution From Mr Spadaro. In 40+ years of rebuilding or replacing wheel cylinders I never ran into that problem but the answer and solution are right on.

 

I had a similar problem today on my 40-48 front juice brakes. I bought replacement wheel cylinders from Raybestos, thinking the ones I bought a few months ago were defective. Wrong, they leaked too. The fix involved shortening up the tabs on the brake shoe stampings....the tabs that engage into the wheel cylinders. They were a bit long and were pushing the cylinder seals too far into the cylinders, allowing pressurized fluid to squirt past the seals and out the cylinder. I used an angle grinder to shorten and reshape the stampings. I shortened the little tabs about 1/8" each. Put it all back together, and so far so good, no more leakage. Why was this required? I have no clue, as usual. LOL. But I my cylinders are '42-'48 Ford, and I have no clue what the shoes are from, maybe an earlier Ford? But it's al part of the fun of assembling these hot rods using mismatched components.