Quote:
Originally Posted by 777stickman
Maybe the shuttle on the P/Valve, for some reason has blocked off the fronts??
|
Nowhere in the factory literature OR in my own experience does the safety valve "block" one or the other hydraulic circuits when it's moved off-center. OTOH, I hear about it blocking a circuit from forum posters fairly often...so maybe there's something to this after all.
If "P/Valve" is short for "proportioning valve", keep in mind that the proportioning valve has NOTHING to do with front brake operation, which is controlled in part by the metering (holdoff) valve. The safety switch is between the two (front and rear) hydraulic circuits.
Quote:
Originally Posted by 777stickman
But there are two tanks for front & rear on the M/C and one piston.
|
There is one actual cylinder, with two pistons end-to end--the primary piston is moved directly by the brake pedal pushrod, or by the power booster pushrod. The secondary piston normally moves in relation to the fluid pressure created by the primary piston, but if there's a hydraulic failure in the primary circuit, the primary piston will move the secondary mechanically.
If there's a failure in the secondary circuit, the primary circuit can still generate pressure when the secondary piston bottoms-out.
Quote:
Originally Posted by 777stickman
If the front seal is bypassing it could lead to less press on the fronts and more to the backs.
|
Whichever circuit fails, creates additional pedal travel to get the other circuit to generate pressure. Having one hydraulic circuit fail cannot induce extra pressure into the other, but the brake pedal will probably be pressed harder to get two brakes to do the work of four; especially if it's the front brakes that fail.