Any GM Techs Around? 96 Tahoe Problem

[jbegler]

I have a 96 Tahoe and am having some brake problems and was hoping someone here could lend me some assistance.

 

Basically everytime you have to hit the brakes hard to stop the pedal locks down and will not release until you turn the car off and restart it and sometimes you have to pull it up with your foot. The brakes work great if you apply them steadily. I have looked for possible solutions but am coming up empty handed.

 

I really appreciate any and all help you can provide

 

Josh

[asepgrad98]

sounds like the brake booster

[GM-Tech]

sounds like the brake booster

 

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Agreed. Nothing else could really do that.

[jbegler]

someone said it might be the master cylinder. Which would be more likley? When the pedal is "locked down" it almost feels like it is hydraulically locked and when I turn the key off it releases the pressure and lets the pedal come up

 

I am really stumped on this problem

 

thanks for all the help

[GM-Tech]

someone said it might be the master cylinder.  Which would be more likley?  When the pedal is "locked down"  it almost feels like it is hydraulically locked and when I turn the key off it releases the pressure and lets the pedal come up

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The master is attached to the booster, but its pistion is not mechanically connected to the booster. So if the piston in the master were to stick in the bore, the booster rod would not be held in that position and the booster would return the pedal. If it were the master, that could certainly keep your brakes locked, but it wouldn't keep the pedal down.

 

Also, shutting off the engine kills the vacuum supply for the booster, giving us another clue that the booster is involved because that releases the brakes. Shutting off the engine should have no effect on a master cylinder whose piston is stuck in the bore.

 

I've seen boosters exhibit this problem. Corvette had this problem several years back.

[Peter_C]

I have seen similar problems on other manufacturers and we cut the master loose from the booster when the vehicle exhibited the problem.

[PunchT37]

Sounds lika a booster problem to me.

[budhayes3]

Definitely sounds like a booster to me, GM-Tech explained it perfectly too.

[jbegler]

Thanks everyone for the help, I will pick up a booster and hopefully that will cure it

 

Have a great weekend