how can you tell if the power booster

[brianstarr58]

for the brakes is bad? had the brakes replaced but it feels like the old manual brakes

[BXX]

for the brakes is bad? had the brakes replaced but it feels like the old manual brakes

 

Sure the brake flex hose didnt get twisted when the brakes were done?? That would kink it and it would feel like old manual brakes..

 

Ive seen it happen soo many times..

[brianstarr58]

I'm pretty sure it's not the flex hose because the pedal got hard before the brakes were done. Actually that's why I wanted new pads because I thought they were getting low.

[tunerlover3]

With the car off, pump the brake pedal for like a minute.

 

Then start the car with you foot on the brake pedal just slightly.

 

When you start the car, you should feel the brake pedal drop about 1/4.

 

If it drops, the booster is fine.

 

[1990lumina]

Jump on the brake pedal for a minute? Any left over assist will be used up in 2 pedal pumps - shit you'd be lucky to get one good one out of a W body lol.

 

 

[tunerlover3]

Most cars you should do it for a minute.

[3pt1lumina]

Sometimes the pedal will be rock hard. Like almost to the point where you can't depress it. Bad booster in that case as well.

[spiderw31]

A hard brake pedal definitely sounds like a failed booster to me. Especially since you mentioned it just started happening out of the blue one day.

[brianstarr58]

How much should something like that cost to have done at a shop? And do you know the correct term for the part?

[tunerlover3]

The brake booster can take like an hour to do in the driveway.

[Schurkey]

With the car off, pump the brake pedal for like a minute.

 

Then start the car with you foot on the brake pedal just slightly.

 

When you start the car, you should feel the brake pedal drop about 1/4.

 

If it drops, the booster is fine.

 

NO. I found by experience (both my Luminas) that the booster can fail and still "test" OK. The power assist goes away, yet it can still hold vacuum; and it will still drop the pedal when tested as above.

 

 

The brake booster can take like an hour to do in the driveway.

You're an animal. Took me WAY, WAY longer than that. I put boosters on both my Luminas; on one of them, I spent more than an hour just getting the brake light switch adjusted. Part of the time was spent playing with the intake manifold and the infamous distributor-plug oil leak.

 

I detailed the procedure with text and photos, and described the results here: (warning: Long and involved!)

http://www.w-body.com/forum/index.php?topic=63764.0

 

 

[White93z34]

^^^^very good information in that post^^^^

 

I read that back a year or so ago now and took it to heart when I was rebuilding my z34, I spent the money for a new brake booster. I can't say how much it helped all and all, as when I installed it I also installed SS brake hoses, and the "big" brake swap on all 4 corners. But what I do know is that this car stops very well for a first gen w-body, going and driving my girlfriends 92' euro which still has all original stuff is 100% different. the pedal feels very good now, and the brakes are responsive.