I recently rebuilt my MC (for my TR-6) because it had a similar problem:
good brakes, but as mentioned, very slowly would sink when holding, as at
a stoplight. I bought a kit from TRF ($50), cleaned the MC thuroughly,
used a hone, etc., and re-assembled with new "tipping" valve. I noted
that the old "tipping" valve looked to be a bit rough. This was about 5
mo ago, and It has worked perfectly.
One trick when rebuilding: you must very carefully clean the bore(s)
afterwards. Use a little silicon brake fluid or alcohol. Rinse
frequently with clean fluid. The perfect tool(s) to have for many such
jobs is a 20 ga. shotgun cleaning kit. Use the brush and cleaning patches
as if the MC were your finest gun! Your life depends far more on the MC
than on your shotgun!
By the way, don't mix the two up....!
On Thu, 17 Aug 2000, Theodore R. Stevens wrote:
>
> Jim Davis wrote:
> [snip]
> >occasionaly the brake pedal will sink quite low without much
> >stopping power when the brakes are applied but will become
> >firm after a pump or two. The problem is becomming progressively
> >worse.
>
> I've had a similar problem, except that so far it's only shown up with
> prolonged pedal pressure (e.g., sitting at a traffic light). I
> disassembled the 3-year-old m/c to replace the (overpriced) seals, and
> found that everything (seals, bore, etc) looked perfect. I replaced the
> seals anyway. There was a *tiny* bit of sludge at the front of the bore,
> which I cleaned out. Bled the system, and everything was just fine... for a
> week.
>
> My suspicion is that there is some cruft in the system, that's keeping the
> seals from sealing, OR that the tipping valve is bad (the rebuild kit I
> bought for $30 didn't contain the tipping valve or its seal).
>
> Good luck, and let us know how you resolve your problem. If/when I figure
> mine out, I'll do the same.
> ---
> Ted Stevens stevens@erols.com
> 74 TR6 Gaithersburg, MD
>
James A. Ruffner
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