I did a brakes on my neighbor 1995 Dodge Dakota 2 wheel drive. I replaced everything ( not the drums themselves) rear brakes shoes, hardware, wheel cylinders. Front was just a new caliper on drivers side ( due to bad bleeder) Flushed out old fluid with new and did four wheel bleeding. Peddle goes right to the floor no improvement at all. I can hear the rear shoes moving when bleeding as well the front are working but they barely stop the truck moving slow. My guess at this point is maybe booster has gone bad? As far as I can see. There is no fluid loss to suggest maybe a leak in the lines. Any suggestions?

 

It was doing the same thing before the work?

Did the master cylinder run dry while doing the brakes?

 

From how bad the brakes were and the rears were in horrible condition my guess would be yes but from what I seen. They were extremely low in fluid. Both rear cylinders were bad. One frozen on one side and the other was leaking bad. I did a reverse bleed on the fronts and had to go old school pump and bleed on back due to not having the correct size to do the reverse.
Are you thinking the master may be bad? I didn't pull it but its pumping fluid to all four brakes like normal. I mean I can hear the shoes in the back moving like they should. You can here the air sound in the cab when you pump the peddle. Hope this helps with maybe finding the problem to fix?
Also while bleeding. I kept the fluid up so no they didn't go dry during the bleeding process.

 

Will the brakes pump up?

 

Yeah, it doesn't take a very good bleed or system to get the shoes to move, but it takes a lot more to get them to drag the drum with sufficient force. HeyYou's question is good, if the brakes pump up with the vehicle off.

 

With the motor off, they seem to have some pressure but when you start the motor. Your back down to the floor. Tried pumping them but to be honest. It doesn't seem to improve at all. I haven't had a bad master cylinder in years so I really can't pin point where the issue is? If he ran them dry. I wonder if maybe the seals are allowing fluid past the pistons that is causing loss of pressure?

 

Either bad master, or you still have air in the lines.Or a leak somewhere....

 

If the old MC piston has been pushed too far with the soft pedal it could indeed have damaged the seals just by nature of age/corrosion/debris built up on the previously unused portion of the piston.

 

I just actually walked over there and with the motor off. It does build pressure pumping but loses it once you stop. With the motor running. Nothing at all. I also found out that it was ran dry so my guess would be the MC is just gone and time for new one.What do you guys think?
Was just thinking. I didn't bleed the MC during this. Do you think maybe I should do a MC bleed, then the brakes again? The reason I am asking this is due to the MC was dry . I found that out after asking him tonight.

 

DId you try bench bleeding the MC? I've done it with the MC in the vehicle and just making up some sacrificial loopty lines to "bench" bleed it on the vehicle. Though, I'd be inclined to replace it given it's probably old maybe even original (?) and maybe been damaged by running dry.

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