Master cylinder leaking

[Cav Trooper]

I have an a2 with a master cylinder leak. It is leaking from the brass block that the brake line connects to. I replaced the block, locktite sealed the pipe plug and installed a new banjo bolt and new washers. I bled the brakes today and the leak is still there after wiping everything dry. I drove it and it is now pulling to the left on hard braking which it did not due before I replaced the parts. I was going to bleed the brakes again tomorrow to make sure I got all air out. Just checked the bottom of the master cylinder tonight and it is still leaking. The banjo bolt is torque to spec and the brake line is tight. I suspect the flare on the brake line but can't see it well enough to tell. Does anyone know if that brake line is available? Where does it run to, under dash or out to the engine compartment?
Thanks,
CT

[Hambone]

I would think you could find a new line or reflare that one, the line runs over to the tunnel, then straight down to a T in the main brake line.

[m3a1]

Those copper washers are aften a bit too hard to really form to make a good seal. I think the solution has been to soften them a bit with a torch. Can anyone confirm?

[rickf]

I just wrote up the annealing process and I thought I posted it but I guess we posted at the same time and I got bumped.
Any way. Take the sealing washers and hang them from a wire in a semi darkened area and heat them with a propane torch to just barely glowing, and I mean just barely. Then let them cool off on their own and clean them up with soap and water and a scrubbing pad if needed, no wire brush. Reinstall and you should be good.

[muttguru]

Hello CT,
someone on the G503 Board was experiencing similar problems to yours.
Before you start fabricating a new brake line, have a look at this:-

2. Copper washers. There is a small one and a large one. The smaller one fits between the master cylinder and the outlet fitting. The larger one fits between the hollow bolt (fluid bolt) and the outlet fitting.
The smaller washer is P/N 5214539. NSN is 5310-00-275-6635.
The larger washer is P/N 5160323.. NSN is 5310-00-777-0223.

If you get these in the wrong order, or if they are both the same size, then you should remove the brass fitting and start again with new washers.

I hope this helps.......
Ken

[rickf]

Good point, I was not aware of the two sizes. Most people will take one to the parts store and get two replacements. If they grab the larger one then there is a good chance of a leak.

[Hambone]

Good possibility it's the washers, clean the fittings up with brake cleaner, you could isolate the leak with small strips of cloth wrapped around the fittings. I know it's a pain working up in that hole.

[m75]

Having dealt with the same leak point, I initially sought similar size washers from local parts house, which allowed the new fluid to decorate the floorboard. I decided to make use of the -20P and -34P, found the part numbers and plugged those into the handy-dandy internet machine. Found a supplier in Texas who set me up with two sets (just in case), and the NOS washers worked like a dream. No leaks! I do believe the difference in both metal hardness (crush-ability?) and thickness were my particular culprits.

[Cav Trooper]

Ok, I replaced the banjo bolt and got 2 sets of washers from TNJ, also new 1/8" pipe plug with brake fluid loctite compatible sealant on the pipe plug only. Also installed the brass NOS connector block. I annealed the washers and cleaned everything up and installed. Bled the brakes and all was good for about a week and found brake fluid seeping again. I'm thinking bad flare on brake line. I removed the brake line today and in the process of making a new one. I have all the correct flaring tools for double flare. If this doesn't work I guess a new master cylinder which I have already acquired. Any other ideas??

[rickf]

Pretty hard to say without seeing where it is coming from. Silicone brake fluid is a PIA when it comes to finding a leak. A trick I have used for stubborn oil leaks and such is to clean the area very well with brake cleaner and blow dry and dust it down with baby powder. Then watch closely for a wet spot in the powder to start showing up. Sometimes you don't catch the beginning but you will get a general idea of where it is so clean it again and repeat watching that one spot.