Master Cylinder
 

Replaced the master cylinder on my 1949 Ford. The fitting on the back of the cylinder where the brake light switch is will not stop leaking. I have a copper washer at the bolt before the fitting and also where the bolt enters the cylinder. No matter what i try it wont stop leaking. Mine you it's just a drop but any leak on the brake system is not good. Are those copper washers suppose to be there or not.

Re: Master Cylinder
 

Yes, copper washers should be on either side of the brass coupler that the brake lines attach to. You might have to replace the copper washers and maybe even the brass coupler with new ones if they no longer seal properly due to corrosion. Also check the hollow bolt that screws into the brass coupler to see if there might be corrosion on the sealing surface.

http://www.vanpeltsales.com/FH_web/F...l_1949to51.jpg

Re: Master Cylinder
 

The copper washers should be there. The leak may be due to the copper washers being work hardened. The old copper washers can be annealed by heating them to a cherry red color and quenching them in a bucket of cold water or you can replace them.

Re: Master Cylinder
 

Thanks for the quick reply. Im going to replace the washers and see if that works . If not I'll have to change out the coupler. thanks again

Re: Master Cylinder
 

some older copper brake washers had raised concentric circles that helped make the seal. The modern ones you get now are just flat copper washers which might or might not seal. It depends on if the part on either side of the washers have the concentric circles or are smooth. I had problems at work using smooth washers with smooth parts. Trying to use the smooth flat copper washers that came with the new calipers. A few times I had to remove the new washers and put the old ones with the concentric circles back in to stop the leaks.

Re: Master Cylinder
 

Several years ago I was able to source the copper washers with concentric circles from Pegasus Racing Supplies.

Re: Master Cylinder
 

I had the same problem on my 49. Used two washers instead of one and stopped the leak.

Re: Master Cylinder
 

try two washer on one side and one on the other

Re: Master Cylinder
 

The washers I have are completely flat and also seem too thick. Copper washers used for brakes are usually thinner. I'll try another set of washers and see if that helps.

Re: Master Cylinder
 

Even new washers should be annealed.

Not made the way they used to be.

Heat them up red and either quench them or let them air cool; either way works.