Brake booster

[landyacht67]

Can anyone tell me what the difference between a drum or disc brake booster is? I changed from drums to discs on my t&c 2 years ago. I never got around to changing the booster, but never seemed to have any ill effects. Now I think my booster is going, and I can buy either a drum, or disc (twice the price). Will I see a gain in braking by going with the correct booster?

Also I assume the fact that when I apply the brakes and I can hear what sounds like a rushing air noise (I suspect vaccuum), and the idle changes, indicates failure of the vaccuum diaphram in the booster. also the brakes dont seem to be stoping as well as they used to escpecially when idling downhill. My idle is @900-1100rpm so there should be enough vacuum.


Julian

[madmax4073]

There is no difference between the boosters. It does sound like your booster is bad, but to be sure check out the vacuum line for cracks. A simple test for boosters is to run the engine, shut it off, wait a minute or 2, then push the pedal. There should be enough vacuum to push the pedal once, or 2-3 times if you have a vacuum canister.

[landyacht67]

Does anyone know if I can put a disc brake master on a drun brake booster?


Julian

[dwc43]

Boosters are the same. Either master will fit it.

[landyacht67]

well for anyone else that runs into this here you go:

We installed the drum brake booster, but the rod that attatched to the pedal was shorter moving my pedal lower down (about 1 inch). also I had 2 inches of pedal travel before my brakes would start to engage. It required both feet pressing down (hard) to fully engage the brakes.

We took out the drum brake booster and put in the disc brake booster, and now I have full progressive engagement how it should be.

The moral: yes you can run the drum brake booster with the disc brake master, but it sucks a$$. Get the right booster and save the headaches.


thanks everyone,
Julian

[dwc43]

You did not adjust the rod in the booster did ya ??

[John Kunkel]

There is definitely a difference in boosters, the drum brake booster is a single diaphram Bendix or Midland/Ross while the disc brake booster is a dual diaphram Bendix unit.

This can be verified in both the parts catalog and the FSM.

[madmax4073]

I think dwc43 and I made the same assumption in that landyacht67 wanted to bolt a disc master to a drum booster already in a car. This will work, however when installing boosters not originally intended for a certain car problems can arise. You need to do some measuring before hand, and/or some fabricating.

[ehostler]

Stating that either booster will work is one thing. Stating that both boosters are the same is another.

DW stated that there is NO difference between the booster. Clearly there is a difference. JK posted what the difference is.

Why doe it bother you that JK corrected DW?

[madmax4073]

It dosen't bother me that JK corected DW, I just stated that I believed that DW and I had made certain assumptions thats all. No problems here, it's all good

[dwc43]

Originally Posted by madmax4073

It dosen't bother me that JK corected DW, I just stated that I believed that DW and I had made certain assumptions thats all. No problems here, it's all good

You are correct madmax. So DW was not corrected in anyway, but that's the way it goes. LOL!!

[ehostler]

Why do you refer to yourself in the second person?

Yes, you were corrected. You stated "Boosters are the same", when the boosters are NOT the same.

[dodger1]

At the risk of hi-jacking this thread, I would like to know whether or not the Bendix dual-diaphragm has any advantages aside from seeming to be more compact (more valve cover clearance) than the single-diaphragm (disc) booster. Anyone?

[John Kunkel]

The dual diaphram booster has more force multiplication because of the added surface area of the second diaphram.