For more info ... Fred Puhn's book on brake systems (forgot title), or the
newer book "Brake Systems" by Mavrigian & Carley.
Mark Palmer
>From: Brian Evans <brian@uunet.ca>
>Reply-To: Brian Evans <brian@uunet.ca>
>To: VEENET@aol.com
>CC: vintage-race@autox.team.net
>Subject: Re: Hard brake pedal
>Date: Tue, 29 May 2001 09:16:57 -0400
>
>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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