2 replies to this topic

[Sidepipes V/C]

So heres my problem:

I have an E200 with drums all the way around that I'm trying to upgrade with a booster.

The problem is I get no brake pedal return. (with or without the booster vacuum hooked up)

When you press the pedal it goes to the floor and stays there, I have to stick my foot under the pedal and pull it back to release the brakes.
I bought a booster/master combo off RockAuto and bench bled it before installing. After searching on here I found a thread of a guy with a similar problem and the master was the culprit, so I went out and got a new master, bench bled it, installed it and have the same result. In the process of this whole brake headache, I've been replacing all the wheel cylinders, springs and self adjusters since most of those were shot.

Does this still sound like a master cylinder problem? Or does the rod coming out of the booster need to be adjusted differently? Something simple I'm overlooking?

After thoroughly searching on here and still being stuck this is basically my last resort before having the thing towed to a mechanic.

Thanks

[Tom Snyder]

The problem is I get no brake pedal return. (with or without the booster vacuum hooked up)

For how many pushes of the pedal without the booster vacuum hooked up?
Found on the net:
Brake pedal sticks down

1. inspect petal assembly
2. separate master from booster
- test booster alone with engine off and engine running
- test master without booster
3. put vacuum res back on. –> test

If the booster does not return there is probably something wrong with the valve that lets outside air or vacuum into the backside of the booster.
The length of the pushrod to the booster & master cylinder is pretty critical too.

[Sidepipes V/C]

 

The problem is I get no brake pedal return. (with or without the booster vacuum hooked up)

For how many pushes of the pedal without the booster vacuum hooked up?
Found on the net:
Brake pedal sticks down

1. inspect petal assembly
2. separate master from booster
- test booster alone with engine off and engine running
- test master without booster
3. put vacuum res back on. –> test

If the booster does not return there is probably something wrong with the valve that lets outside air or vacuum into the backside of the booster.
The length of the pushrod to the booster & master cylinder is pretty critical too.

 

First let me answer your question:

 

Without the engine running you can almost bottom the pedal out in one stroke.  It'll spring back slightly but way short of typical.

Possibly due to a poor bleed job? 

 

I separated the master from the booster and conducted the following "tests" 

- took a dowel and pushed in the back of the master where the booster rod would go.  It sprung back just fine.

 

- fired up the engine and had the wife step on the brake pedal.  Pushrod came out.  When told to let off the pedal, the pedal stayed in place.  

 

So my question now is, with the master detached should the booster have caused the pedal to return to normal?

Maybe I don't have enough vacuum to the booster to pull the pedal back into position?