On 17 March, George wrote:
> I rebuilt the brake master cylinder on my '72 Spitfire last weekend with a
> genuine Lucas kit from The Roadster Factory. Everything came apart and went
> together just fine--but yesterday I discovered a slow leak on the seal between
> the reservoir and the cylinder (right over the tipper valve). That sorta ticks
> me off because I spent several minutes with a small electrical screwdriver
> carefully removing some rust that had formed on that seat... I thought it
> looked PERFECT before I put in the new seals and reassembled it.
>
> I tightened the screws that hold the reservoir to the cylinder evenly and
> snugly--I don't think that tightening them will stop the leak. I think I read
> that it's OK to use a little RTV silicon on these O-rings to prevent leaking,
> yes? If that's not appropriate, what would the wisdom of the list advise?
George,
I had a similiar problem after rebuilding my TR6 cylinder last Spring and I'm
wondering whether you may have done what I discovered I had done. I'm not
familiar witht the Spit's master cylinder/resevoir setup but maybe this is
relevant.
While reattaching the cylinder to the resevoir, both units were upside down on
the bench. The bottom of the TR6 resevoir is not parallel to its top. Being
now upside down, this caused the cylinder's mounting surface to slope. This
slight angle caused the heavy cylinder to slide ever so slightly "downhill"
which resulted in the primary circuit's o-ring (the tipper valve) to not be in
proper contact with the flat portion of the resevoir. The slop in the
cylinder's mounting holes around the screws was enough in my case to cause it.
You're right, no amount of tightening will solve this problem. I just had to
keep an "uphill" pressure on the cylinder as I tightened the 4 screws. I
discovered this by accident upon disassembly.
Hope this helps. Good Luck!
Gary
'75 TR6
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