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Brake Pedal Guidelines
Wilwood pedal assemblies and
integrated balance bars have been
designed specifically for racing
applications. Properly set up, this
assembly will allow for the precise
adjustment of front to rear brake
bias. The advantages of an adjustable
balance bar and dual master
cylinders are:
• Brake proportioning can be
adjusted by use of different sized
master cylinder bores for front and
rear brakes.
• Front to rear brake balance can
be fine tuned by adjusting the
balance bar.
• With two independent hydraulic
systems, should one master cylinder
fail, the other system may remain
functional.
Brake pedals should be mounted securely. When possible, keep the master cylinder reservoir level higher than
the horizontal plane of the calipers to prevent excessive fluid drain back which can result in double pumping
of the pedal. If this is not possible, a two pound residual pressure valve should be plumbed into the brake line
at the exit of the master cylinder to prevent fluid drainback. (Do not confuse the two pound valve with the
ten pound version; the ten pound valve is for use with drum brakes only).
Brake pedals should be free to return when no pressure is being applied, allowing the master cylinder pushrod
to return to it's undepressed position. In some cases, the master cylinder spring (internal) may not be strong
enough to fully return the pushrods; in this case an additional pedal return spring can be used. There are two
important items for consideration:
1. The brake pedal should have an adjustable return stop on it when a strong pedal return spring is used. This
prevents the master cylinder from excessively banging the snap ring stop inside the master cylinder bore (visible
under the rubber boot). Adjust the stop so that the pedal stops returning at the point when the master cylinder
piston retracts against the snap ring (Fig. 1).
2. The master cylinder piston must fully retract. If the master cylinder piston is not allowed to fully retract
when the brake pedal is not applied, the primary inside seal will not return past the small pressure relief hole
(visible within the master cylinder reservoir on some master cylinders). This can cause excessive residual line
pressure and contribute to brake drag and overheating condition, (Fig. 1 detail A).
