cluelesscutlass

hi. my 72 cutlass stalls and dies when i press on the brake. i assume its some sort of vacuum problem. this has only happens in park since i havent driven the car yet bc the combination valve needs to be replaced. thanks

cluelesscutlass

oh yeah another quick question. i have drums in the back and had a look at the shoes. how thin can the rear shoes get before they need to be replaced?

rustyroger

The shoes should be replaced when they are worn down to 1/16" at any point.

Sounds like your combination valve going bad and stalling when you press the brake pedal are connected issues. If the pedal travels too far it will allow the vacuum from the manifold to escape, a symptom of this is a hissing noise when you press the pedal, have you noticed this?.

Roger.

cluelesscutlass

Haven't heard the hissing but wasn't listening for it. Will listen for it tommorrow. the pedal does go way down and then it stallsThe combination valve is in the mail, I can't wait.

69442C

If you have a vacuum gauge, see what your reading are idling and when you press the brake pedal. If the reading drops significantly when you depress the brake pedal, you may have a problem with the brake booster. And if you do, just search the forums for replacing the brake booster as there has been recent activity on that subject.

cluelesscutlass

Thanks for the tips. I hope it isn't the brake booster, I'm runnin out of money.

1965cutlassragtop

I was thinking check ur fast idle screw.....does it stall only when u press the brake?? will it stall even if u just take your foot off the gas and let it coast down the road?? If it's only when u press the brake, then yes I would say it's most likely vacuum related. But if it does it even if your not pressing the brake, just slowing down, then it might just be a carb adjustment...fast idle screw setting or air/fuel ratio.

1965cutlassragtop

Nevermind, u said u've only kept it in park, it's not the carb if it seems to run fine at idle. Fast idle adjustment would not come into play unless you get the car moving....good luck!!

66ninetyeightls

More than likely a faulty vacuum booster. Disconnect & plug the vacuum line at the booster> if the problem goes away there you go.

rustyroger

Fix your brake hydraulics before you worry about the booster, if you still have a problem after you get a good pedal then you need to hit your wallet but not before.
Roger.

Lady72nRob71

Spending the money on a new booster is the easy part.
Replacing it is the hard part...