Brake booster

Maintenance/Repairs
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1

i put a new brake booster in my 1988 Acura legend and now the brakes won’t release after being applied a few times but when you shut the car off for a wile the brakes release. i have bled the brakes what could be causing this

2

Perhaps it didn’t need a new brake booster, but a new hose to one or more wheels. Will it move when the brakes are not releasing? If so, all four are not holding it. Probably one is. If it will move, drive it just a little, and then feel each wheel near the wheel studs for heat. The one that’s hot is the one that’s hanging up and needs a new hose.

There is also a possibility that the rod between the master cylinder and the booster is incorrectly adjusted so that the booster is holding the brakes in an applied condition.

3

A factory shop manual will have the information you need to correctly install the booster and master cylinder. The rod between the booster and brake pedal arm and the rod between the booster and master cylinder may need specific adjustments…

4

all 4 hold but i dont let it get to the level that it would keep the car from moving not to mention the motor can over power the brakes easily. yes the booster was the part that failed the lines are new and the booster has a hole from rust and it wont hold a vacuum. when it completely failed i still had brakes just not power brakes

5

i have the shop manual and it seas see pedal height (so i measured and set the new one to the same height) , install master cylinder and bleed system (witch i did) , connect the vacuum hose (witch i did). i followed what the book sed to the letter and it is not working. i have also tried the connecting rod in meny lengths and no matter where it is there is the same problem.

6

I sounds like the rod is either incorrectly adjusted or something else is mechanically interfering with the ability of the brake booster to return to its inactive position. When the booster is in that position, the vacuum is on both sides of the diaphragm. When the brakes are applied, valves open to vent the backside of the diaphragm to ambient and close off the orafice between the back side and the front side such that vacuum is only applied to the front. In your case the vacuum is being constantly applied to the front of the diaphragm and the back is remaining vented to ambient. That’s a rod adjustment problem or a problem with some other mechanical interference in the rod’s travel. Perhaps the brake lever stop is misadjusted or something of that sort.

Are you sure you have the right booster part number?