pt76jon

I am having a problem with my 2000 Firebird, what it is doing is appling the brakes slightly while I am driving down the road. The braking system is all stock, and the abs is not functional! It somehow overcomes the powerbooster and actually applies the brakes, I can unplug the vac line to the power booster and then it releases the brakes again until I drive it. The check valve is in line and functioning correctly, only allowing flow in one direction.
I was just wondering how I can take care of this problem and if anyone else has ever had it before?
Thank You!

stevieturbo

Pedal adjustment might be wrong ??

If the pedal was adjusted too close or tight, then it might be closing the seal within the booster, allowing vacuum to add a little assistance.

Strange problem though....

johnmeador609

and i thought i had it bad havin to ride the brake and flash the converter to keep the vacume up on my blower car because im to lazy to install a vacume canister

stevieturbo

Why would you have trouble maintain vacuum in a blower car ? it should be the easiest of them all if the vacuum source is take of the correct location.

pt76jon

No brake peddle is not adjustable, I have even tried shimming out the master cylinder and it still does it! Today I totally eliminated the power booster and drove the car and it still did it!
After that I got to looking at it and thought that maybe the brake lines are getting too hot, so I covered all of them with high temp coverings and drove the car and it still did it.
What I am going to try next is to take the abs motor assembly appart and take all the electronics out of it and put it back on the car and try again!
What am I overlooking?
Thanks!

johnmeador609

ysi in a fox body mustang its not all that easy. Its not ALL that bad but it takes some getting used isnt bad at the track or at speed but at idle in traffic it gets annoying.

stevieturbo

If the vacuum source is taken from just after the throttle blade, then unless you have a huge cam in there...

Vacuum should be good.

Do you run a non-return valve in the line too ? That should maintain vacuum for a couple of presses in itself.

johnmeador609

not hijacking his thread but its a custom grind have no clue on grind but is very large no return line. not an issue now seein how im parting it out and going to be starting on another f-body project.

johnmeador609

I personaly dont think its a problem with forced induction. Try Suspension & Brakes.