Brake Booster Questions

[patmckinneyracing]

I have some questions concerning my brake booster on my 1980 malibu. From what I can see based on the pictures on autozone's website, it is a dual diaphram, not the smaller single diaphram. Which design is better when it comes to stopping power? I was told that you can't simply switch between the two. Why is that if it is a true statement?

The other thing is autozone lists multiple single and dual diaphram brake boosters that have sub-notes listing "for heavy duty brakes" or "non heavy duty brakes". How do I tell if I have heavy duty brakes or not?

FInal question is how often or quickly do brake boosters wear out? What are some of the symptoms that a brake booster may be going out? Mine is stock and I have no idea on how to tell if it is time to replace it. In my conscious it would make me feel better knowing that is one less thing that could break.

 

[78_oldcruiser]

when a brake booster wears out the brakes will get hard to push and dont want to stop. if you ever have 1 worn out you will be able to tell right quick. if you are looking for a daul the part # you need is 54-17271, if you are wanting to go ahead and change mc and bb together(which i find is easier) you will need part # 54-1272. both you can get at orielly's auto parts which is the cheapest i have found and is the same setup i used with my 78 cutlass cruiser wagon. be sure to change the filter when you change the booster. also you can change the bb easier if you drop the steering on the inside, if not its a pain in the *ss to get to the bolts

 

[Bonnewagon]

Early boosters were huge, because they had the room to mount them so no big deal. Then as cars shrunk in size, the dual diaphram was needed to fit. It equaled the single in power but was smaller in size to fit the cluttered engine bay. Boosters can outlast the car but when they go bad, you know it. Usually the pedal effort goes way up since the vacuum is not assisting and the big spring inside, which is there to give some pedal effort, is fighting you. Very rarely, the pedal drops slowly to the floor while your foot is on it, just as a leaking MC would feel. Each is an internal defect cured only by rebuild/replacement. If you hear a WHOOSH sound from under the dash as you brake, that is merely the air rushing in to fill the booster to replace the air sucked out by vacuum. There is a felt muffler in the bellows that the push rod goes through and when it is missing or shot you get the sound. I'd say if yours is working fine, leave it alone.

 

[oldtinsmith]

patmckinneyracing,
I did a web search and found something very interesting! Go to montecarloss.com, forum "DO-IT-YOURSELF", page 1, go down 14 posts to B-body dual diaphram swap into a G-body ( by Z65 Paul), from 1-17-10. Just something to think about!

Doug

 

[patmckinneyracing]

I'm sure that I have the g-body DUAL diaphram booster. I don't have the pancake style single diaphram as mentioned a lot in that montecarloss post.