Was he in your class? /ubbthreads/images/graemlins/idea.gif
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I would strongly recommend against using a residual pressure valve to "solve" your problem.
Pad knock back is caused by a rotor that is not spinning true.
It's primary symptom is increased pedal travell.
If you're having problems with increased pedal travell due to pad knock back, machine or replace the rotors, check the hub for run out and your wheel bearings for freeplay.
Problems in any of these areas will knock the pads back from the rotors and increase the pedal travel as the pads have to be moved a considerable distance before they contact the rotor and begin to do work.
Using a residual pressure valve to hold the pad against the rotor will allow the pad face to reach temperatures above it's design parameters, and may very well lead to outgassing... (you won't like that, to put it mildly.)
In addition, the body of the pad acts like a heat sink, and you will end up transferring a whole sh*t ton of heat into the caliper, potentially causing more serious issues like damaging the square cut o-rings, boiling the fluid and the like.
But, the number one reason I would recommend against this is that when you stop, the pad will be solidly up against the rotor.
This will cause the rotor will cool unevenly...
Best case is a warped rotor...
Worst case is a serious case of pad material transfer as the pad matrix breaks down, making the brakes all but unusable.
If you're running the 3kgtvr4 set-up, be sure to check your calipers for alignment, and the caliper pistons for freedom of movement.
The pads will tell that tale.
If they are tapered, investigate and repair the cause, fire in some fresh pads, machine/replace the rotors and you're good to go.