Im pretty sure I know what it is but I want a few opinions. My brakes recently went out and I found that one of the problems is there was a broke line on the rear axle from wheelin. New line installed and brakes bled but now there is no pressure in the pedal at all no brakes what so ever. Let me know what you think

 

There are 2 things left in the brake system that may affect pressure - master cylinder and pressure regulator. I'd start with master cylinder by applying a repair kit or replacing it.

 

where is the pressure regulator, and what about the brake booster?

 

Brake booster can't make brakes act that way i think. The only thing it can do with brakes is providing no pedal pushing assistance, so you'll have to jump on it to make your truck stop. I suppose (i was not looking for it yet) that a pressure regulator must be located at the lower end of a firewall or at the frame near the rear axle. Anyway it affects only rear wheels brakes. My guess about what happened is that small seals inside of a master cylinder somehow moved from their positions when the pressure lowered due to a brake line damage, and now master cylinder can create no pressure, so you can feel no feedback on the pedal.

 

I replaced the master cylinder bled it out and everything, at first I had a little pressure, but now still nothing. My buddy was pressing the brake pedal down as I was watching the engina bay and I discovered the brake booster was expanding every time he pushed down, my thoughts are that its not supposed to do that!!!

 

Brake boosters will have nothing to do with a hydraulic issue, as Fast Hampster was saying they provide pedal assistance, and that is all. When pedal pressure is achieved you will agree. More than likely air is still the problem. When line broke fluid level got low and air was pulled into the master. Remove master cyl first and bench bleed it before replacement, could save you $$.

 

By the way, the brake booster has it's own pushrod that engages the master cylinder. This pushrod needs to be adjusted to the proper length. Usually it's fine and you just bolt on the master cylinder, but the booster expanding sounds like the pushrod is extended too far out putting a lot of pressure on the booster.

And hopefully you bled the ABS unit too, on the frame rail.

 

well guys i appreciate your help. I had already thrown a new master cylinder on bench bled and all, still no real pressure. so next I put on a new brake booster, and low and behold after a few minor adjustments of the push rod, PEDAL PRESSURE=Brakes!! I havent yet bled the abs unit, not sure if its even on the truck anymore. Pretty sure it was bypassed and a staight line feeds the rear. It isnt 100% but I think its going to be the best I can get for a little while. I have more important issues to deal with, like the wheel falling of while I was doing 35 down a dirt road! WTF? the rotor center section was so rusted that the last time I torqued the lug nuts on the lugs loosened up and began to spin. For some reason I cant get the hub or rotor to budge so some high end threadlocker and a impact wrench are in order!!! thanks again. Now onto my new FSB 6" lift project!

 

Do yourself a big favor get yourself a Motive products pressure bleeder I have one they make bleeding brakes easy. The one I have is the Pro Bleeder Kit which has adapters to fit most domestic master cylinders, and they have other adapters that will fit everything else.

http://store.motiveproducts.com/shar...unt2=194236397

 

Ill have to check that out, not too bad of a setup!