Think of this as a leverage problem - the lever is your foot pressing
against the caliper pistons, with a bunch of stuff in between. The
problems could be, in order of what I think is the probability, the front
master cylinder is too big, both master cylinders are too big, the front
calipers have too small pistons (could be rears instead of fronts, for
example), the pedal leverage is wrong (my car came with a clutch pedal that
had been shortened, for some reason, thus reducing the leverage ratio of
the pedal. This could have been done to accommodate a small foot, and the
difference made up by using a smaller master cylinder), and so on. You can
check these things out if the cylinder turns out to be right. In any
event, reducing the size of the master cylinder increases the pressure it
can produce, reducing the effort and creating a longer pedal motion to move
the same amount of fluid. You then have to move the pivot of the balance
bar for more rear pressure ( or change both front and rears together) and
that will change things too.
One thing to think about before ordering cylinders is are the discs and
pads in good shape, and could you try softer, more aggressive pads? Glazed
discs or pads can reduce brake efficiency.
Brian
At 01:57 PM 5/28/01 -0400, you wrote:
>I could use some advice as to how to deal with a really hard brake pedal on a
>Lotus 51.....It requires a tremendous amount of preasure on the brake pedal
>to get the car to stop.I think master cylinder size is a factor. Does anyone
>know what would be considered the "right" or normal size cylinders for a 51?
>Any other ideas?
>Thanks,
>Jerry Burr
Brian Evans
Director, Canada
MCI Wholesale Internet Services
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