Andrew,
Start by bleeding the brakes - it sounds like you may have some air in
the lines. Remember that when bleeding the brakes, you start at the
wheel furthest from the master cylinder (passenger rear) and move
progressively closer (driver rear, passenger front, driver front).
This will ensure that you have no air left in the lines.
If that doesn't work, it sounds like you need a m/c rebuild. It's
possible that your m/c was rebuilt previously but maybe needed to be
honed out to get rid of some pitting, and possibly it was honed out too
much. Unlike an engine, you can't get oversized parts for m/c's, so if
you do too much honing, you basically have an unusable m/c. At that
point, you either get the m/c resleeved, or you buy a new m/c. I think
currently it's more economical to just buy a new m/c (ie: resleeving
plus the cost of a rebuild kit is only barely cheaper than a new m/c),
but that was a discussion that took place several months ago on the
list, so maybe prices have changed by now.
Tim Holbrook
1971 TR6
--- Andrew Packard <apackard68@comcast.net> wrote:
> Oh wise listers:
>
> Starting about a week ago, I have had some trouble with brake
> pressure in my
> TR250. There has been no loss of fluid, but when I first apply the
> brakes, I
> get very little resistance and get down to the floor with only minor
> braking
> force being applied to the wheels. I've gotten in the habit now if
> braking
> early and pumping two to three times quickly to get the pressure
> necessary to
> stop easily. Obviously, this isn't the safest of driving conditions.
> I'll be
> taking the car off the road soon to install Herman's Toyota
> transmission
> conversion and Richard's 3.92:1 Nissan differential very soon, so
> I'll address
> the brake issue then.
>
> I haven't done any diagnosis of the brakes yet, just the pressure
> pumping
> experiments to see how quickly I can build pressure in the system to
> stop. I
> haven't had the car for two years yet, so I have no idea if the MC
> and servo
> are original, rebuilt, or replaced new at some point. If I were to
> guess, I
> would say that the MC had been replaced at some point, but the servo
> is
> original. Are my brake system symptoms similar to anything you have
> had and
> what was your diagnosis and solution?
>
> Thanks as always for your shared knowledge and wisdom.
>
> Andy
> CD6521L
> CD6746L
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