94 3500 2 wheel drive 6bt, a friend took it to a shop to have front brakes done. (metal on metal but had good peddle). they put pads, rotors, & master cyl. he got it back & brake peddle solid for a second then leaks to floor. took it back to shop they replaced master cyl. again but could not fix the problem.
i have replaced everthing but the rubber brake lines, master cyl. 2 times. if i clamp off front brake lines close to calapers, brake peddle is solid at the top & does not leak down. anyone have any info on this?
i am 51 worked on heavy equipment & diesel trucks sense i was a kid. i can't figure this truck out.
Thanks Rick

 

What brand master cylinder are they putting on there?

If clamping off the calipers stops the pedal going down, I would start looking real hard at them. The fluid has to be going somewhere......

Might try bleeding the fronts REALLY well again.

 

Clamping the rubber lines is not a good idea. I'd replace them now,regardless if they are the problem or not.

 

bought it from Car Quest not sure of the brand of MC, i don't like reman parts but no one has new MC. not available from dealer or napa. i have by passed abs & porpurtioning valve. i ordered the brake lines pick them up today. thanks for the info

 

Sorry, but that's , Another not so good idea.

 

Whats wrong with bypassing the abs guys? Mine leaked from the servos and I said to my self **** I dont wanna buy a hundred dollar part and have the computer decide when I apply too much brakes. (rear abs only) I just took the line from the back and got the one from the front and put a union in there. Now it thinks it has abs but i doesn't.

 

I know I'm sounding like a dick, but, another bad idea.

 

The rear abs doesn't work worth a damn anyway. Worst case is, you might get an ABS light if the computer thinks it needs to do the abs dance, and nothing much happens when it tries.

A real flare union is ok. Compression fittings are not. (and are not legal either.)

 

I used a real flare union except for the fact that the lines were already long enough so i literally jsut bough 1 union onstead of making new flares. I would never use a compression fitting. sliding on fittings and flaring with a union only take 20 mins if accessible anyways. And yeah man you're a major dick. Haha Just kidding. Better safe than sorry on brakes.

 

Hey, how do you know my first name?