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TR2/3/3A TR3 Brake Plumbing

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MGTF1250Dave

MGTF1250Dave

Jedi Knight
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Aloha All,

I started surveying and repairing or replacing the brake system on a recently acquired TR3A. When removing the master cylinders for the brakes and clutch, I broke one of the fluid pipes between the reservoir and the brake master. I replaced both masters for clutch and brake and fabricated new pipes for each from the reservoir to them. I had a small leak at the connection to each of the masters which only became noticable over time. I thought the problem was the double flares I made on the pipes, so I decided to replace the pipes with factory made flares. I still have the leaks. The problem seems to be the machined mating surface in the masters have small "nicks" that make a tight seal impossible. Is there a tool to smooth these surfaces? Could I use lapping compound and pipe with a good flare to clean them up? As a last resort, I am considering using an O-Ring, since this is not a high pressure line. Any help would be greatly appreciated. This problem is keeping the car off the road where it belongs.

Safety Fast,
Dave
 
[ QUOTE ]
...The problem seems to be the machined mating surface in the masters have small "nicks" that make a tight seal impossible....

[/ QUOTE ]

Well, I've been waiting to see what suggestions you got. Since nothing else is forthcoming, I'll propose the handyman's secret weapon -- JB Weld.

Not actually seeing the nicks it is difficult to know how effective a solution this would be but I have mended many things and heard of many more that are under much more stressed situations than the feed line to the master cylinder.

Key would be to get it very clean, use only enough to fill the nick & a skosh more and dress it down -- your lapping idea may work for that.

I'm not too crazy about ading an O-Ring in there. Good luck.
 
I'd be really surprised if you could get JBWeld to adhere very well if there are any brake fluid traces in there. Could you get a machine shop to resurface the mating surface? You wouldn't need to take much off, by the sound of things.
 
Aloha Dave I am sure not being able to drive the 3 on the island is a major bummer. Seems strange that there is pitting on new (?) master cylinders but your idea may work. Maybe a couple of other thing that you have probably already tried. Are you getting full bottom on the fittings. Is there any squash to the flare where it mates to the MC? Is there any kind of thread seal that might help? It's strange, as you said, there is no pressure so it should not require much of a seal. Good luck!
 
Aloha and thanks for the suggestions,

The problem seemed to be that flares were not perpendicular to the seats, so I was only getting a good seal on about half the connection. Forceful tightening was making a "new moon" cresent depression on one side of the seat. Because of the small hole and depth of the seat in the master cylinder body, I didn't think I could use J B Weld or a similar epoxy product and get a smooth and even surface. I decided to use a thin neoprene washer between the pipe and the seat and it has stopped the leaking. I haven't tried lapping it with a pipe with a good flare as a tool, but will some time in the future on a spare master cylinder and let you know if it works.

Safety Fast,
Dave
 
Remember, stopping is more important than going. Nuff said.

Bill
 
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