Master cylinder unions.

[paul connor]

Hi all.

I have had a few recent issues with reproduction  parts, which I suspect are chinese cheap copies- the problem being keeping the fluid on the inside of the unit. They have required a union on the fluid exit port, which enables ½ pipe and unions to fit, a converter basically. This is stainless steel and threads into the master cylinder, but will not stop weeping. I have tried tightening, and again more, but I'm at the stage the unit will crack soon. Has anyone used any form of compound on threads such as these to assist in a seal, such as loctite 270? Which appears on the tech-spec to be fluid proof?

I'm aware this isn't common practice, I'm just throwing it to the forum for ideas?

The union I mean is on the right side of the picture with the black bung in. Please note this picture is reference and not from the store in question.

Edited July 23, 2019 by paul connor

[john1950]

Have you tried a Copper washer or Dowty seal between cylinder and connection

[paul connor]

Good idea! I guess that wasn't in my chain of thought, mostly as it wasn't supplied with the unit I guess!

[john1950]

No problem let us know if it does or does not work.

[Grasshopper]

Had many issues with an M55 truck hydrovac unit leaking and that was all OEM parts - Dowty seals did the trick in the end. 

[paul connor]

I have used a copper washer, as I could not source a dowty seal fast. 

Appears to have done the trick, but I'm waiting 24 hours before I proceed. Just to make sure it's not weeping.

 

Thanks for advice. I guess it's pretty obvious really, but when a unit comes with a union installed right from new, you dont expect to have to remove it and put a washer in!