Re: A discussion of brake problems
Originally Posted by
onehundred80
Some free play is necessary to allow the expansion of the brake fluid as it warms up otherwise the fluid expansion would start to move the caliper pistons.
So increasing the MC size has an adverse effect on braking.
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So you're hypothesis is that the brake fluid within the brake lines expands enough when heated that "free play" back to the pedal exists to prevent brake caliper closure & excessive pad/rotor wear due to dragging. Like James, I'm not sure I agree with this hypothesis as any thermal expansion of brake fluid from increased heat should be handled within the MC reservoir which has room for fluid expansion when filled to proper level. Is the brake system a closed system? In theory it is, but if there is a weak link it would be the MC cap which may or may not be an absolute seal. Are there check valves to prevent back flow to the master cylinder? Probably - To keep the brake lines full & minimize pedal travel when braking is required. There must be a pressure relief valve in the system to allow the pressure in the brake lines to reduce to a "steady-state" condition once the pedal is released, allowing the calipers to retract and excess brake fluid flows back to MC reservoir. And if this is the design, I can't see any force being applied to the MC actuator due to fluid thermal expansion. Gotta look at the brake system PFD to confirm. However, the viscosity should be impacted and that could contribute to a need for increased pedal travel to develop braking force pressure. Gotta think about that some more.
But I do agree with your second hypothesis. Increasing the size of the MC would have an adverse impact on required pedal travel to generate sufficient braking force.
Just thinking out loud.
Last edited by dedwards0323; 04-10-2018 at 07:57 AM.