Thread: Front brakes locking.

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wellllll-------
if your calipers aren't releasing it won't push back, buttttttt-----if your pedal isn't retracting the plunger , then your calipers won't have the pressure released---both ends of the master don't close/vent at the same time--that way pressure can be applied to one end of the car momentarily before the other--keeps the fronts released as a driver keeps litely touching the pedal---you know-the guy(or gal) thats in front of you that keeps tapping the pedal and blinking his stop lites in your face!!!!

Take the calipers off and spin the rotor to make sure all is OK.

And I ran into some mopar and GM pads that were almost perfectly alike except the wrong ones bound up and the correct ones were fine--don't remember which way it was but you need the correct pads/calipers/rotors

Originally Posted by jerry clayton

And I ran into some mopar and GM pads that were almost perfectly alike except the wrong ones bound up and the correct ones were fine--don't remember which way it was but you need the correct pads/calipers/rotors

I bought the whole front suspension and brakes as a kit so I hope they are matched right.

Kits have been known to have the wrong parts in them from 1-800streetrod suppliers

I think the brake parts that were real close but wrong were Dodge 1/2 pickup 2 wheel drive fronts and the GM metric stuff that is commonly used on rods---pads were a little wider in the cross direction and bound up on where rotor radiused out from the disc toward hub

Two things to look at with the rotor. 1. Make sure the rotor is at a right angle to the spindle 2. bent mounting bkt..

I figured out the calipers were not binding up after all. It only seemed like it but in all actuality when I pried up on the caliper it wasn't realigning it, it was pushing the piston back and relieving the pressure. I replummed the MC to the proportioning valve and adjusted the brake pedal and I think everything will be fine. I haven't had a chance to take it for a test drive because I still have to reposition the brake light switch to make up for the moved pedal but I think everything will be fine. Still not sure why the pedal goes down when started but I can spin the wheels just fine when it is running and up on jack stands.
Thanks again everyone for your patience and help!

Originally Posted by Louey

(Still not sure why the pedal goes down when started)


As long as you have all the air out of the system, AND, you have the rear brakes adjusted properly, your pedal will not drop. It will stay in the high position. The rear shoe adjustment controls how high the pedal is on that first pump of the pedal.

I have disk in the rear as well. I guess it is possible that I still have some air. I will bleed them again and see what happens.
thanks

I have an emergency brake but it works off a separate set of drum brakes inside the rotor.

I bled the brakes again but same thing with the pedal so I may remove the front residual valve and see what happens.

Originally Posted by Louey

You have me a little confused now. Your brake setup, can you post some pictures of it. Is the master above on the firewall, or below, under the floor ?

the mc is under the floor. I deleted the pics from my computer but they are on page 3 of this thread.

Your scaring me now.
I'm waiting to get my frame blasted so I haven't started to put my four wheel disc brakes together yet.
Sure hope you get this figured out soon.
It will be worth it when you getter done.
But hurry up.

Okay I finally got it out for a test drive and my brakes are fine now. This is a little embarrassing but this is what I found. When I built my floor and frame I aligned everything the best I could. Come to find out my pedal was too far from the floor and not giving me enough travel so I extended it (too far actually) and now I have enough travel to push the master cylinder all the way. So when I started I had the push rod adjusted too far which caused my front brakes to drag. When I adjusted the rod to where they were not dragging any more, even though I still had about 6 inches of travel (my guess as I never measured) it wasn't enough.
It may be a good thing that this happened because with your help I did find out that I had my MC reservoir for the front hooked up to the rear. that may have caused a little head scratching as the pads wore down. Form what I found out the whey these under floor master cylinders are the brake pedal is heavy enough to push down on it's own so who ever said earlier that I needed a return spring was right.
Can anyone tell me if the guy at speedway was right? He told me a MC with a larger bore (1 1/8") would make my pedal have even more travel then with the 1" bore that I have now. I would like to reduce the amount of travel needed to work my brakes if I can.
My next challenge is to get my wipers working.

Originally Posted by Mr Smith

Okay I finally got it out for a test drive and my brakes are fine now. From what I found out the way these under floor master cylinders are the brake pedal is heavy enough to push down on it's own so who ever said earlier that I needed a return spring was right. My next challenge is to get my wipers working.

HMmmmm.. guess how I knew about that one? LOL... yep, btdt... and I believe the speedway guy is correct.