39 master cylinder leak at banjo bolt

[electricman]

I have a leak around the copper washer at the bolt head side of the banjo bolt. So far the washers have been replaced twice, the bolt has been replaced once and the master cylinder has also been replaced with a USA made unit. Been working on these systems for 50 years and am now really stumped. Any suggestions? Would appreciate any comments that don't suggest a retrofit back to the mechanicals. Thanks

[Zeke3]

Anneal (soften) the copper washers by heating them to a cherry red color and quench them in a bucket of cold water. Then make sure the sealing surfaces are clean and reassemble with the newly softened washers.

[bbrocksr]

Originally Posted by electricman

I have a leak around the copper washer at the bolt head side of the banjo bolt. So far the washers have been replaced twice, the bolt has been replaced once and the master cylinder has also been replaced with a USA made unit. Been working on these systems for 50 years and am now really stumped. Any suggestions? Would appreciate any comments that don't suggest a retrofit back to the mechanicals. Thanks

Anneal the washers to make them softer so they will conform to the surface better. Also inspect the rings on the brass block.
Bill

Zeke can type faster.

[Krylon32]

Sometimes I've had to file the surface the copper washer contacts on the master cylinder for a better sealing surface. I use a small sharp bastard file.

[Ken/Alabama]

If the bolt is new it’s probably a tad too long. I’ve ran into this before.

[electricman]

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Thank you gentlemen. Tomorrow I will flatten the washers with sandpaper on a piece of glass, anneal the washers and check the bolt length against an original one. Your suggestions have kept me from buying a can of Barrs leak in desperation. Will report back.

[aussie merc]

put a small ruler across the brass block to see if its still straight and flat they will cave in slightly over the years if not, its better to replace them if you can as filing can reduce the sealing rings and they wont be as effective also check that the sealing face on the bolt isn't distorted they both rely on being flat

[electricman]

Yippee ! I have brakes again. Following the suggestions of annealing the washers, using a file with some layout ink on the back of the master cylinder to smooth the surface, checking the bolt length and the brass block ( they were ok ) The leak is fixed. Thanks to all your helpful comments I am on the road.

[Zeke3]

Great to hear, thanks for letting us know it corrected the problem.

[john greco]

Had the same problem , drove me crazy then found out there was a tiny split it the brass fitting that the banjo goes threw , check very closely or replace it