Bad brake booster.

Corabar

Registered User
I have a 1989 Supercoupe 5 speed. I recently discovered that i was leaking brake fluid from my master cylinder into the brake booster. At the time i didnt think it would cause any harm as long as i kept the fluid level up as i tried to make some money to replace it. After about 2 weeks of having fluid leak into my brake booster i began to develop an idle problem. Im guessing the brake fluid ate through the diaphragm. I am in process of replacing the brake booster and master cylinder. But i just wanted to list all my problems im having and make sure it just these parts. When the car is running it will idle arouns 500 rpm and stay there. It also is misfiring. Is the misfiring be caused by the vacuum leak from the brake booster? Or is it possible that my brake fluid that ate through the diaphragm got sucked into my intake and ate away at my seals and gaskets and ruined any spark plugs. When i check my oil i notice there is a hint of yellow fluid (possibly the brake fluid?) Im just so lost.
 
I have a 1989 Supercoupe 5 speed. I recently discovered that i was leaking brake fluid from my master cylinder into the brake booster. At the time i didnt think it would cause any harm as long as i kept the fluid level up as i tried to make some money to replace it. After about 2 weeks of having fluid leak into my brake booster i began to develop an idle problem. Im guessing the brake fluid ate through the diaphragm. I am in process of replacing the brake booster and master cylinder. But i just wanted to list all my problems im having and make sure it just these parts. When the car is running it will idle arouns 500 rpm and stay there. It also is misfiring. Is the misfiring be caused by the vacuum leak from the brake booster? Or is it possible that my brake fluid that ate through the diaphragm got sucked into my intake and ate away at my seals and gaskets and ruined any spark plugs. When i check my oil i notice there is a hint of yellow fluid (possibly the brake fluid?) Im just so lost.


Your misfiring could be caused by a bad vacuum leak but I believe your issues are non related. Are your brakes functioning normally? If so I don't believe your booster to be defective.

List out your mods if any. That also helps. What does your vacuum gauge read at idle and does your engine idle smoothly? If you have good vacuum and your engine is idling smoothly I will almost bet your misfiring is ignition related.

With regards to your oil. I doubt very much if you have brake fluid in your oil. If you did it wouldn't harm your gaskets and seal that quickly. Brake fluid is caustic but it would probably take a year to cause damage you are describing.
 
I have a short ram air intake and catalytic converter delete. My vacuum gauge does not read properly and no matter how much i rev i cant get it to 12 pounds of boost. I have replaced the iac, pcv, coil pack, and ignition control module. When i had to press my brakes they wouldnt be as reactive and i had to push them far for them to work. This also happened at the same time as the idle problem. But let me be more specific. When i first developed the idle problem it wasnt bad as look as you rev'd it and held a steady rpm with the gas pedal which led me to the iac. Replaced it and nothing changed. But now it has gotten worse and will only idle ag 500 rpm amd sometimes as low as 100 rpm but it never dies. And also it backfires no matter what the rpm is.
 
The boost gauge says i have more vacuum than usual. Could this be caused by my bad brake booster snd be responsible for the misfiring?
 
Sorry for the several grammar mistakes. My autocorrect doesn't like to correct me sometimes. And i meant to say *it MISFIRES no matter what the rpm is* not backfires.
 
A 1989 Thunderbird SC didn't come with a vacuum brake booster. Were the brakes converted to a vacuum boost system? Or was the car originally a base model car? Or none of the above?
 
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