disc brake pedal low

[plumduster]

i have just changed my 1970 duster over to front disc brakes i installed a set of rebult kelsey hayes 4 piston caliers installed new disc brake proportioning valve. on the first test drive the brake pedal went half way to the floor but when i pumped the pedal they were to the top with good braking the problem is when the car set for some time the first pump on the pedel is again half way to the floor i have bleeded the lines but has not helped i dont know if i still have air in the lines or wright master clyinder the one i have on the car wright now is a tandem with one large reservoir for the front brakes and one small one for the back

 

[69Dartconvt69]

I am guessing you've never bled a set of Kelseys before. Bleeding them mounted on the car is never going to get all the air out.

 

[69Dartconvt69]

If you have a power bleeder you can. Easiest trick is to pull them off, slide a chunk of 2x4 in and have someone pump them while you rotate the bleeder to the high side and do this several times for each one and then you'll be set. Make sure you put a little hose on the end of the bleeder unless you like a mess. Same thing I've done for Corvettes too.

 

[67Dart273]

I don't think this is a bleeding problem. If it was you would not be able to "pump up" to a good pedal--it would still be mushy.

I think either the rears are too loose (adjustment) or the master bore is a mismatch to the disc/ rear cylinder bores.

 

[69Dartconvt69]

{I don't think this is a bleeding problem. If it was you would not be able to "pump up" to a good pedal--it would still be mushy.

I think either the rears are too loose (adjustment) or the master bore is a mismatch to the disc/ rear cylinder bores.}

Then I will just leave the mechanicing advice to you, I don't know notin anyhow after 33 years of turning them wrenches. I'll just be over here mindin my own busniss.

 

[67Dart273]

{I don't think this is a bleeding problem. If it was you would not be able to "pump up" to a good pedal--it would still be mushy.

I think either the rears are too loose (adjustment) or the master bore is a mismatch to the disc/ rear cylinder bores.}

Then I will just leave the mechanicing advice to you, I don't know notin anyhow after 33 years of turning them wrenches. I'll just be over here mindin my own busniss.

With your hostile attitude, that might just be a great idea

 

[69Dartconvt69]

With your hostile attitude, that might just be a great idea

Hostile my :bootysha:.

My appologies plumduster, was just trying to lend a hand and didn't want to piss all over your thread.

I stayed away from this site for quite a while and I think I will get back to it. Hey mods, can you delete my account please, I'm through here.