The Ford Barn

Rayfry · 03-22-2023, 08:33 AM

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.

mcgarrett · 03-22-2023, 09:03 AM

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

Zeke3 · 03-22-2023, 09:04 AM

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.

Rayfry · 03-22-2023, 09:40 AM

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

Flathead Fever · 03-22-2023, 01:01 PM

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.

tubman · 03-22-2023, 01:15 PM

Sponsored Links (Register now to hide all advertisements)

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

38coop · 03-23-2023, 06:38 AM

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

Terry,OH · 03-23-2023, 06:49 AM

try two washer on one side and one on the other

Rayfry · 03-23-2023, 09:12 AM

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.

rich b · 03-23-2023, 09:17 AM

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.

03-22-2023, 08:33 AM	#1
Rayfry Member Join Date: Feb 2019 Location: Philadelphia Pa Posts: 67	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.

03-22-2023, 09:03 AM	#2
mcgarrett Senior Member Join Date: Dec 2013 Location: Waxahachie, Texas Posts: 949	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

03-22-2023, 09:04 AM	#3
Zeke3 Senior Member Join Date: Dec 2014 Location: Columbus, IN Posts: 1,406	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.

03-22-2023, 09:40 AM	#4
Rayfry Member Join Date: Feb 2019 Location: Philadelphia Pa Posts: 67	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

03-22-2023, 01:01 PM	#5
Flathead Fever Senior Member Join Date: May 2010 Location: Yucaipa, CA Posts: 1,095	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. Last edited by Flathead Fever; 03-22-2023 at 01:11 PM.

03-22-2023, 01:15 PM	#6
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 10,303	Re: Master Cylinder Sponsored Links (Register now to hide all advertisements) Several years ago I was able to source the copper washers with concentric circles from Pegasus Racing Supplies.

03-23-2023, 06:38 AM	#7
38coop Senior Member Join Date: May 2010 Location: Cocoa Florida Posts: 180	Re: Master Cylinder I had the same problem on my 49. Used two washers instead of one and stopped the leak.

03-23-2023, 06:49 AM	#8
Terry,OH Senior Member Join Date: May 2010 Posts: 4,743	Re: Master Cylinder try two washer on one side and one on the other

03-23-2023, 09:12 AM	#9
Rayfry Member Join Date: Feb 2019 Location: Philadelphia Pa Posts: 67	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.

03-23-2023, 09:17 AM	#10
rich b Senior Member Join Date: May 2010 Location: Minnesota Posts: 1,825	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.