Brake "Woosh" and Pump Up...

[Stinger]

The brakes on my 85 SVO work great but don't start working until a few inches from the floor. I've bled the lines and it didn't change a thing. The two things that seem to identify the problem are:
1) It makes a "woosh" noise when I push on the brake pedal (which I've always heard means the booster is bad).
2) If you pump it 3-4 times it will brake with the pedal high like it should (which normally means there is air in the lines or the MC is bad).

Odd thing is one of my buddies had the exact same problem and he replaced the booster with a new unit and replaced the Master Cylinder twice and the problem is still there. I don't want to waste money on the same parts as him and not fix the problem.

Anybody have the same problem and fix it?

Stinger

[SVOeric]

I think the woosh is fairly normal -- the booster usually isn't bad, unless it leakes.
If you push on the pedal, and hold it down,(not while you are still pushing it down) you should not hear air escaping. -- if you do, the booster is leaking.

it sounds like you just have air somewhere-- are you bleeding fronts, and backs?

[Eyelawdoc]

You either have internal leakage in the master cylinder (bad piston seals) or air in the lines. When you get the pedal low and the brakes work, does the pedal feel hard or soft? If it feels soft and spongey, ther is air in the lines. If it's hard, replace the master.

Don't forget to bench bleed the master before installation.

[venomizd93]

what type of fluid are you using.....I hear the Ford "blue" stuff is the best around...even some GM guys use it. That's the consensus among cobra owners who want better stopping power, especially in fox bodies. I use valvoline syntec blend barke fluid....in the cobra and the SHO....the SHO actually seemed to have better pedal response. Just a thought. haven't gotten to the SVO yet...it's covered outside in the frozen tundra under 2 ft. of snow. Covered I said!!!!!

[Stinger]

Originally posted by SVOeric
I think the woosh is fairly normal -- the booster usually isn't bad, unless it leakes.
If you push on the pedal, and hold it down,(not while you are still pushing it down) you should not hear air escaping. -- if you do, the booster is leaking.

it sounds like you just have air somewhere-- are you bleeding fronts, and backs?

Nope, only leaks air when I'm pushing it down.

Bleeding both fronts and backs.

You either have internal leakage in the master cylinder (bad piston seals) or air in the lines. When you get the pedal low and the brakes work, does the pedal feel hard or soft? If it feels soft and spongey, ther is air in the lines. If it's hard, replace the master.

The pedal feels normal once it gets down low (pretty hard).

what type of fluid are you using

I have no idea...I just bought the car in November and didn't start driving it until late December. I will assume it's just regular ol' brake fluid though.

Stinger

[Eyelawdoc]

My opinion is that it is the master cylinder. Let us know how the brakes work after you replace it.

[GAboySVO]

I agree with Eyelawdoc. Replace the master cylinder.

Here is a test to perform: On a slight grade, pump the pedal until it is in the high position (normal). Then hold the brake pressure to keep from rolling back down the hill. If you master cylinder is bad, the pedal will gradually move to the floor or the car will start to roll.

[Stinger]

Originally posted by GAboySVO
I agree with Eyelawdoc. Replace the master cylinder.

Here is a test to perform: On a slight grade, pump the pedal until it is in the high position (normal). Then hold the brake pressure to keep from rolling back down the hill. If you master cylinder is bad, the pedal will gradually move to the floor or the car will start to roll.

Thanks for the tip...I'll check it out.