Bob---Your brake pedal fade could be from two or more reasons. When air
is in the brake/fluid system it responds to heat by expanding and
feeling more like the pedal is solid, after a pump or two. (Sustained
hard pressure will still make the pedal drop, but won't be as noticeable
as with ordinary braking.) This might go towards explaining the
different feel you get when weather temps drop.
Check for fluid leak(s) at all of the wheel cylinders and the MC. Brake
fluid stays around awhile, so a leak should be noticeable. Check for
seeping directly under the MC reservoir, on the servo unit.
If no leaks are found, a "bleed" is still advisable.
Complete exchanging of MC's is not usually necessary, unless it just
makes you feel better, or the present one has been rebuilt many times.
Kits are available that replace the parts that cause the leaks. Same
with wheel cylinders. Brake honing tools can be purchased reasonably at
auto parts stores, and these can clean up the bores so that new seals
work as in new units. These rebuilds are not necessarily risky business.
You can check the results of your work in your own driveway or garage,
before taking to the road. If your pedal is firm again, you will have
had the pleasure of doing your own work, and confidence in the next job
you tackle.
Dick T.
'73
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