Mushy pedal and then normal.
08-28-2011, 01:36 PM
#1
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Mushy pedal and then normal.
Sometimes, if my '83, 4 wheel disc, Crossfire sits for a while, I have a mushy brake pedal right after start up. It's like I need to push the pedal to the floor to get any braking power. After a few minutes it's goes back to normal. I suspect that this is vacuum related. Could a vacuum leak cause this? Should I be suspicious of my booster?
What do you guys think?
What do you guys think?
08-29-2011, 07:57 PM
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Re: Mushy pedal and then normal.
What is your vacuum at idle? Normally, it should be over 10" of vacuum. Any lower than that the vacuum brake booster will probably not work very well.
How to test a vacuum booster:
With the engine off, pump the brakes till you bleed off all of the vacuum in the booster (usually six or eight pumps will bleed it all off). Pump the brakes up and hold them. Start the engine. The brake pedal should immediately be pulled down towards the floor. If not, you either have a bad brake booster or not enough vacuum.
How to test a vacuum booster:
With the engine off, pump the brakes till you bleed off all of the vacuum in the booster (usually six or eight pumps will bleed it all off). Pump the brakes up and hold them. Start the engine. The brake pedal should immediately be pulled down towards the floor. If not, you either have a bad brake booster or not enough vacuum.
01-16-2012, 09:18 PM
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Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Mushy pedal and then normal.
What is your vacuum at idle? Normally, it should be over 10" of vacuum. Any lower than that the vacuum brake booster will probably not work very well.
How to test a vacuum booster:
With the engine off, pump the brakes till you bleed off all of the vacuum in the booster (usually six or eight pumps will bleed it all off). Pump the brakes up and hold them. Start the engine. The brake pedal should immediately be pulled down towards the floor. If not, you either have a bad brake booster or not enough vacuum.
How to test a vacuum booster:
With the engine off, pump the brakes till you bleed off all of the vacuum in the booster (usually six or eight pumps will bleed it all off). Pump the brakes up and hold them. Start the engine. The brake pedal should immediately be pulled down towards the floor. If not, you either have a bad brake booster or not enough vacuum.
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