I would think that the front brakes would come on before the rears, The large front reservoir moves fluid first, then the small rear reservoir, but I'm not finding that to be true. My rears come on before the fronts. What controls the order that the brakes engage? It does make some sense that there would be better control with the rears starting the slow down.
I have a stock system, with T in place of proportioning valve, and yes, I do have the lines connected correctly.
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my view of the master cylinder is the first piston is moved by pedal force. as first piston pressure is created, that pressure moves the second piston, thus both pistons devolp pressure at the same and provide fluid to the caliper pistons at the same time and pressure (UNTILL the Propertional valve comes into play)
some cars have relief valves that delay one circuit like front disc/rear drum designs
@rrs1 posted:I would think that the front brakes would come on before the rears, The large front reservoir moves fluid first, then the small rear reservoir, but I'm not finding that to be true. My rears come on before the fronts. What controls the order that the brakes engage? It does make some sense that there would be better control with the rears starting the slow down.
I have a stock system, with T in place of proportioning valve, and yes, I do have the lines connected correctly.
Please describe why you believe the rears brakes are engaging before the front brakes. How do you know the front brakes are engaging at all? Is it under hard braking, a panic stop, gentle braking or all braking? If your rear brakes are indeed doing more braking than the front, it's surely a maintenance issue.
Getting all four wheels off the ground and then pressing the brake pedal. The rears lock up first.
Brake calipers rebuilt, new master and booster, SS lines, pretty much everything. New fluid, no air for sure. The shuttle valve was also removed, so basically straight lines from master to calipers.
The car does stop okay, but pedal feel is lots of slop and then ON.
my view on calipers. . .
I don't have the diameters (more so, I just don't feel like researching)
just assuming some things based upon the front calipers are 4 piston and the rear is a single.
while the master cylinder is pushing fluid to to both front and rear at the same time. brake fluid pressure will not build up until the pads are just touching the rotor. I'll assume the single rear piston has less volume change to go from "seal retracted" to contacting the rotor.
SO in absolute, the rear brakes are "applied" first then. (but very very little stopping). the rear touching will let rear pressure circuit devolping a minute pressure to cause the MC pressure to put more volume to the front untill they just touch.
Now both front and rear fluid circuits will build up pressure equally as pedel is pressed.
the amount of stopping force generated by the same pressure now will be greater in the front due to the greater caliper piston area
Just my SWAG!
That's a good explanation jfb. Pretty simple and logical. I will go with it as all normal then.
