Re: Ian's brake travel

["Jay Mackro" <jmackro@domain.elided>]

"Ian Lomax" <ilomax@domain.elided> had written:

>Subject: Long brake pedal travel
>Ever since the spider came out for the summer, it seems like the brakes are
>"misadjusted".  There seems to be more pedal travel than I remember before
the
>brakes engage (about 3"?).  I bled the brakes last week with no apparent
>change.  They work fine once they engage, and they don't "pump-up" so I
don't
>think there is air in the lines.  Any ideas?  Can I adjust the MC so the
>brakes engage earlier?

Ian:

Sounds like you have a problem (big help, huh?).  No, there is no adjustment
in the linkage between the pedal and the m.c.  When everything is working
correctly, the "adjustment" is handled hydraulicly - that is, the m.c. just
settles into the right position.

I'd guess that you have a problem in either the m.c. or one (or more) of the
calipers.  The fact that the brakes work OK - once they engage - is a
clue, though I myself can't decode it.  The fact that this symptom arose
after the car had been in storage is another clue - one that I can build on.
Calipers will often freeze up after sitting awhile - dried brake fluid
creates
a crud that freezes the piston.  Usually this prevents the piston from
retracting after the brakes have been applied (the pressure created by
the m.c. when you step on the pedal is enough to overcome the crud,
and push the cylinders out).  Might this have occurred?  The symptom
is that the car is hard to push in neutral on a level surface - ie, the
brakes (or at least one brake) doesn't release.  Another common
brake symptom on older cars is the flexible hoses swelling shut,
again allowing the pistons in the calipers to extend, but not to retract.

Now, why either of these problems would cause the symptom you
describe (ie, 3" of dwell in the brake pedal) is beyond me, but they
might be a start.

Good luck, and be careful about driving a car whose brakes are
suspect.

Jay Mackro
'76 spider + a few others

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