Greetings all,

Having a problem with my brakes. Recently my brake pedal has become hard to depress. It almost feels like applying the brakes with the key off. I've check the power booster and overall braking system and nothing looks wrong. I checked the vacuum lines and no leaks/cracks found. No work has been done on the brakes recently, except when I did a 100k tune up (thanks to all who helped with that job) I cleaned the brakes (at the wheels) with some brake cleaner and added a very small amount of fluid to the master. The car was fine for a week or so after work. Any thoughts appreciated.

Thanks

1995 SSEi

The premise behind power brakes is the brake booster, without vacuum you have no power brakes. You mention checking the vacuum lines. With the car running, pull off the booster hose and feel the vacuum wth your thumb. The car will run horrible most likely because of the excess air, but you should feel the vacuum.

This is also a good line to pull for running GM Top End Cleaner

Anyways...if the pedal is hard to depress....I'm leaning towards the Booster being shot.....

In between the maxifuse relay center and the windshield wiper motor assembly, there'* another black box that looks like an extension of the maxifuse cover. That'* a vacuum accumulator or manifold. There are 2 very small fittings underneath, so check to see if either are broken. If they are, they'll rob vacuum from your booster.

I've driven a car with a bad brake booster before and the engine would stall when the brake pedal was pressed. THe pedal also would go to the floor very easily. This was on a 75 Cutlass so I don't know if it'* even similar to the Bonneville. I've never felt a newer car with a bad brake booster so I'm unsure. but, it would make sense that a stiff brake pedal would be caused by a bad booster. Just unsure why my experience was the opposite.

It would depend on where the booster was losing vacuum. I think if it lost the vacuum and dumped it to atmosphere inside the booster, you could stall the motor and depress to the floor.

If the vacuum leak were BEFORE the booster, you'd have a firm pedal.

I just went out and checked the various suggested areas. Pulled the check valve out and had good vacuum pressure to the power booster. Sitting in the car I could hear a quite sucking sound and the engine would start idleing pourly when the brake pedal was pressed.

Sounds like a bad booster. Can this be repaired (seal)? And if not whats a good price for a new booster?

Thanks again for all the help!

Boosters can be replaced, they don't go bad very often...no idea of a price for you.

Junkyard.

'93 won't fit but a '94 will. Two bolts to the master cylinder and four nuts up under the dash.

You have to drop the steering column and use about 18* of extensions on a deep socket. 13mm I think... could be 15mm.