Brakes Bad brake booster!

91GTstroked

15 Year Member
Jun 14, 2007
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Well,

Some have known that I been fighting some gremlins lately! I'm wondering if a bad brake booster can be a contributor to it?

A few weeks ago, I my car died on me while applying the brakes. The brakes are not stock.

I have 13" front 03 cobra brakes, rear 11" cobra brakes, 93 cobra master cylinder with a 3-2 port conversion, and summit racing bias adjustment on firewall.

Today I noticed while pushing the brake pedal it made a hissing sound. After some research, I need to replace it.

So could this cause a vacuum leak throughout the engine and cause problems?

I'm looking at a replacement, and I can only find a reman on Rock Auto.
 

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If the leak is bad enough, yes. Look at the large line from the booster to the vacuum tree. The other large line goes to the intake as a vacuum source. If the booster is leaking bad enough it would be like disconnecting that line.
 
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Well,

Some have known that I been fighting some gremlins lately! I'm wondering if a bad brake booster can be a contributor to it?

A few weeks ago, I my car died on me while applying the brakes. The brakes are not stock.

I have 13" front 03 cobra brakes, rear 11" cobra brakes, 93 cobra master cylinder with a 3-2 port conversion, and summit racing bias adjustment on firewall.

Today I noticed while pushing the brake pedal it made a hissing sound. After some research, I need to replace it.

So could this cause a vacuum leak throughout the engine and cause problems?

I'm looking at a replacement, and I can only find a reman on Rock Auto.
You need look no further. The hissing sound is the brake booster seal leaking.
Happened to me. You get a big vacuum leak when you push the brake pedal.
You're lucky if you can find a reman. The reman facility is closed to the COVID19.
I sent a part off for reman since they had none anywhere. It's stuck in the O'Reilly warehouse.
Most, if not all, of the remans are done by Cardone.
 
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You need look no further. The hissing sound is the brake booster seal leaking.
Happened to me. You get a big vacuum leak when you push the brake pedal.
You're lucky if you can find a reman. The reman facility is closed to the COVID19.
I sent a part off for reman since they had none anywhere. It's stuck in the O'Reilly warehouse.
I found a reman on Rock Auto. Some have mentioned painting them because the stuff that's on them don't last.

Hopefully I don't have to bench bleed the master cylinder. I was planning on changing brake fluid this year. Looks like sooner than later.
 
No brake bleeding necessary if you can separate the master cylinder from the booster without removing a brake line.
1-man brake bleeding is easy with an air compressor & a fitting for a spare fluid reservoir cap.
Dial down the pressure all the way & let it leak around the cap. Less than 5psi will push the fluid to the bleed screws.
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No brake bleeding necessary if you can separate the master cylinder from the booster without removing a brake line.
1-man brake bleeding is easy with an air compressor & a fitting for a spare fluid reservoir cap.
Dial down the pressure all the way & let it leak around the cap. Less than 5psi will push the fluid to the bleed screws.
IMG_1496.JPG

1589324862686.jpeg
I have a similar kit, forgot what it's called, but works great. I hope I can remove booster without disconnected brake lines, but it looks like a very tight area.
 
My BB was installed improperly at the factory, about 1/2" offset to the driver's side. It was obvious after getting it out, the firewall hole was not a clear hole, used a step drill bit to enlarge it.
The MC stud is so close to the shock tower I needed a mid-length socket. Bought a 14mm 1/4 inch drive deep well & had a friend turn it down on a milling machine. I think I had to remove one of the brake lines.
 
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Got it all done yesterday. I didn't have to remove the lines on the MC.

Brakes feel good, no more hissing sound when pushing on brake pedal.
 

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