4 replies to this topic

[Scruffs]

Hi All,

Having trouble getting a union to seal into my master cylinder. I'm using a yellow band master cylinder and have just re-done the bulkhead pipework to plumb in a Wilwood proportioning valve.

It is the lower union that's leaking (rear - correct?), the one with the larger thread. I formed a single flare into the end of the pipe, but the shoulder of the union bolt was bottoming on the taper before the pipe seals. Result: fluid everywhere!

In my frustration I took a file to the union bolt and chamfered the shoulder on the end, which has appeared to sort it, but I'm wondering where the problem came from...the OE pipes are long gone so I can't check what was on there...

Does the lower port feed into larger diameter pipe?

Should I have used a double flare? - I can't see a corresponding seat in the M/C though, only a taper.

Thanks for any light you can shed on this one

Al

[Scruffs]

If you'll excuse me i'll just give this a cheeky bump - I'm going for bleeding attempt #2 tonight and would like to avoid another paint stripping excercise if anyone could help me out!

Anyone NOT had any problems with new copper pipes into the lower ports of yellow band masters?

Cheers

Al

[SolarB]

I'm certain the master cylinder needs a double flare (though I'm at work at the moment and can't check).

[Ethel]

Single flair (pointy rather than trumpet shaped) and standard size pipe, the thread is M12x1. If the union is for larger bore pipe the fit would be poor on the flare and the union would screw in further. Not all unions are the same so you may find a more suitable one. Minispares do a conversion pipe set, might be worth it rather than taking chances.

[SolarB]

I'm certain the master cylinder needs a double flare (though I'm at work at the moment and can't check).

Ethel's right. I always forget which flare is which, I meant single (pointy) flare.