help it wont stop!!!

[heartnurse2]

hey yall,

I have a 92 f350 crew cab. it has no brakes. when i get in it u can push on the pedal and it goes to the floor slo but for sure. i have replaced wheel cylinders, bled them several times., new calipers again bled and rebled. the rear abs light is on on the dash, i just replaced a sensor on the frame under drivers floor. now the catch is this it acts just likes i have a fluid leak is how the pedal goes down and this has been going on for quite awhile!! now heres the catch IT DONT USE ANY FLUID. i have not used or added fluid for months this is getting to me cuz i cant figure it out!!\\

Jay

[Dave]

Master cylinder or booster sound like they are out

[OLDTOM]

I agree with the master cyl. The fluid leaks past the seals internally and never leaves the system. If you go the reman. route replace the booster also. If the master has failed the booster is not far behind.

[heartnurse2]

sorry forgot to mention new as well. as fact i have changed MC 3 times. but how would booster be bad? i thought all it did was make the pedal ezier to push, was all. when i disconnect the vac line from it i have the same problem but the pedal is a little harder.

Jay

[mrnecsteve]

Am pretty sure there is a hydraulic valve /actuator in the booster.I have had a situation where the vacuum line sucked up leaking brake fluid that was leaking internally.

[Rob]

i would replace the master and the booster, just to be safe.

[tweener]

That vintage ford uffered from "over active boosters"

You won't find this written many places, but at the shop I worked at we would install 1 ton master cylinders to fix the problem.

You may have to Grind out the mounting holes on the MC with a carbide burr....

What it did was make it harder for the booster to push the MC (1 ton MC has a larger piston diameter)

this may be what you are experiancing

We saw most of the problems on the E-vans (150's and 250's) I would say 89-95 model years...

[UnrealAntidote]

Originally Posted by tweener

That vintage ford uffered from "over active boosters"

You won't find this written many places, but at the shop I worked at we would install 1 ton master cylinders to fix the problem.

You may have to Grind out the mounting holes on the MC with a carbide burr....

What it did was make it harder for the booster to push the MC (1 ton MC has a larger piston diameter)

this may be what you are experiancing

We saw most of the problems on the E-vans (150's and 250's) I would say 89-95 model years...

In the original post it says this vehicle is a 1ton so I assume the MC was replaced with a 1ton MC. I dont think this is the problem.