ok i replaced the MC and the Proportion valve. do i have to bleed from the proportion valve at all?
i bled the MC and from all four wheels.
but my back rims get covered in dust while there is hardly any on the fronts.
when im goin above 45 if i try to stop i gotta push harder on the pedal then i should.
did i miss somethin?
What do you mean you “bled the master cylinder”?? When bleeding the brakes you do so only from each caliper. You will not undo any lines at the master cylinder, proportioning valve or any other brake line connection. ONLY at the bleeder screw on each caliper.
In regard to the dusting issue. Are you running the same compound pad front and rear? Is there a chance your calipers are stuck? Parking brake not releasing all the way? This dusting issue was not happening before you did your brake work?
well i replace the MC and proportion valve but we bled out the MC before hand. ive bled the syastem and no air comes out. but i cant remeber if the dusting was ahppeneing before or not.
im pretty sure the parking brake is releasing, but maybe that could be it, ill have ot check that out. and yes the pads are the same front and rear. i think im just gna bleed em again and see if i get air.
I’ll ask you again, what do you mean by “bled the master cylinder”?
Bleeding the master cylinder is not a procedure I’ve ever heard of, and quite frankly it doesn’t make any sense. Brakes are bled at the calipers. If you’re bleeding fluid from anywhere except the caliper bleeder nipples you’re doing it wrong.
Are the parts new or used? What proportioning valve are you using. It should be a “40 40” prop valve.
when you put in a new MC, you have to “bench bleed” it before installation. i had to replace mine a while back, and there are instructions included with the part telling you to do it, and explaining how. that is what he is talking about.
Care to enlighten me on exactly what that entails?
The Helms manual mentions nothing of this procedure and I’ve installed numerous master cylinders (used, new aftermarket and new oem). I’ve never received instructions on how to “bench bleed” a master cylinder. And I’ve never had any issues w/ the ones I’ve installed.
Colin: It’s a chevy-based website, but the concept is universal.
http://www.superchevy.com/technical/chassis/brakes/0509sc_bench/index.html
Chillax bud. It’s real, it’s important, and he’s right for doing it.
G2FTW: Definitely check your parking brake adjustment. If that’s not it, it may be that the calipers are starting to sieze in the rear. Try to work the piston back like you’re installing new brake pads. If it’s pretty tough to screw the piston back in, you’ll definitely want to either rebuild the calipers yourself or buy remanufactured calipers to replace them.
Rebuilding is not too tough, and is covered in the Helm Manual. You basically disassemble the caliper (compressed air helps get the piston out), remove the old seals, install new ones, and put the piston back in. I popped my cherry on a set of dual-piston legend calipers and it’s far more difficult with two than with one.
If you’d rather not get into that much detail with the car, remanufactured rear calipers can be picked up at just about any auto parts store.
Good luck, and keep us posted whether either item is at fault. 
Hmm, very interesting. I may try that next time (but I’ll probably forget) seems like it may be a good idea but not necessary. Thanks for the info ferret.
You could also try a gravity bleed.