Disc brake questions need help now please!!!

[RIDER68]

ok i put the disc brakes on my 44 and went and put the explorer disc brakes on the rear put all new brake lines in it put the new proportioning valve in it for disc to disc and im running the bronco vaccum power brakes and i cant get any pedal, it works if you pump it up but there all the way at the floor then if u let it sit for a couple of seconds you go to push the pedal down there is no pressure and i had them bled at a shop and no air was seeming to come out but i just cant figure out why they arent working and none of the lines are leaking PLEAS HELP ME i need it driveable by tomorrow morning

 

[thumping]

Did you replace the master cylinder? Even if not you may have to bench bleed it as it sounds like you may have some air trapped in it. Did you use an adjustable proportioning?

 

[broncopete78]

Have you tried bleeding at the master cyclinder and the proportioning valve? Hold the pressure and crack the lines going in and out of each. It's worth a shot. I am not fameliar with explorer calipers, are they adjustable? do the pistons screw in and out and not set right?

 

[half cab]

What about your power booster? Did you have it already or get a new one?

 

[DirtDonk]

If you changed either the master OR added the booster, did you set the rods to spec?

Paul

 

[RIDER68]

well i bought the proportioning valve i dont know if its adjustable and how to you set the rod up to specs?? like i got some brakes by not pushing all the way to the floor and not cracking the bleeders all the way open but all the pedal is at the floor and maybe it is the rod how do you adjust it? thanks

 

[Boss351]

Disc brakes require more volume sounds like you need a bigger master cylinder

 

[RIDER68]

i figured out i had the lines going from the master cylinder to the wrong side on the proportioning valve and it built a LOT of pressure but then i bled the brakes just to make sure and i lost ALL my pressure and slowly built some back up. it has brakes but only at the floor board

 

[stanz]

what master cylinder are you using? is it the same one you were using for rear drums?

 

[RIDER68]

ya i think thats whats wrong i think i have to drill out one of the ports so i can get more fluid

 

[TBS-POPS]

Did you grind the Knuckles on the 44 if you are using the chevy conversion??? If not this is a typical problem. also you dont need a prop valve with disc/disc. with a stock mc you need to pull the risidual check valves from behind the line seats when going to disc.

 

[Broncobowsher]

Did you put the calipers on the right way?

No, it isn't a joke. If you put the left on the right and the right on the left, they do fit. But the bleeders are on the bottom of the caliper piston bore. Air rises. You need the bleeder on the top of the bore to get the air out.

Go look at the calipers, is the bleeder on top or bottom?

As for the rest, countless people have done disk brake converions with no changes to the master cylinder. In fact I eventually went back to a stock master cylinder after following some very poor advise on getting a bigger one. Half the time I didn't even use a proportioning valve, and when I did it was only for a little tuning. It had brakes without it, just not balanced as well as I would have liked.

To tell front or rear, if you still have rubber lines take a pair of vise grips and pinch the rubber line. Fairly tight, but not permenate damage tight. If you clamp off the fronts and the pedal suddenly feels good, the problem is in the fronts. Braided stainless line can't do this, it kinks for good.

 

[half cab]

ya i think thats whats wrong i think i have to drill out one of the ports so i can get more fluid

I'm not sure I would do this?,but I'm no expert!!

(i have to drill out one of the ports)

 

[RIDER68]

i just took the knuckles off of a 79 f150 with the disc brakes on i and bough new calipers and the bleeders are on the top of the calipers.