What are my options for a power brake booster?

[MaximRecoil]

The brake booster in my '69 Charger is leaking (though, strangely, it stops leaking when you press hard on the brake pedal). When I converted to front disc brakes last year, I used a '76 Volare master cylinder. Can I also use a brake booster from a '76 Volare, or any other 4-bolt Mopar booster from that era?

[ODZKing]

If you have the original, I would have it rebuilt. Booster Dewey is supposed to do good work. I plan on having them redo the one from my 73.

[MaximRecoil]

It is cheaper to buy one that's already rebuilt, especially if one from e.g., a Volare will work.

So no one here knows if other 4-bolt power boosters from the '70s are compatible?

[ws23rt]

Compatible would mean does it bolt up?  If you have your old booster than you have the bolt pattern, piston position, etc. to  match your old leaky one with what you want to use.
The question you may be asking is. If it does bolt up will it boost enough to match what the leaky one you have should? A good question?
I suspect that any boost beyond what you have with your leaky booster would be a success. 

[Dino]

Is this the original drum booster that's leaking or did you go with another one.  If it's the drum booster and pressure felt alright then I'd get another one of those.  They're pretty cheap, or used to be anyway.  You could just open it up and see if it can be fixed, you have nothing to lose but some time.  I wouldn't think the Volare booster would bolt right up but the modification may be minimal. 

[MaximRecoil]

I asked Richard Ehrenberg about using a power booster from something like a Volare or Diplomat, and he said:

"There's lots of linkage differences, you'll need a 70-down B-body booster (if you must have one at all!)"

On another forum where I posted a picture of my current leaky booster, someone pointed out it is a booster for drum brakes (which I knew, but I didn't know it made a difference), and that I should have a Bendix dual diaphragm booster for disc brakes because disc brakes require more pressure than drum brakes. My brakes actually work fine as-is, even with the leaky drum brake booster (they feel and stop about the same as the brakes in my 100% stock 2001 Dodge Dakota 4WD), but additional boost from a dual diaphragm booster certainly wouldn't hurt anything.

The parts store rebuilt booster for a '69 Charger (A-1 CARDONE Part # 5473501) appears to be a single diaphragm Midland type for drum brakes, and a dual diaphragm Bendix booster from e.g., Booster Dewey is expensive. However, on the other forum, someone messaged me:

"I have a disc brake booster that was on my 69 coronet for a couple of months. I only took it off because it wasn't the correct looking booster. It worked fine , just looked wrong for my resto. If interested I'd sell it for $50 plus shipping."

"It is a Bendix dual diaphragm. Was newly rebuilt unit when installed. Is just shaped a bit different than a 69 b body calls for. Since my car is 100% stock I changed it as soon as I found the correct one. It worked and functioned fine."

So I think I'll buy that one.

[Dino]

Sounds like it may be a C body booster.  But for $50 I wouldn't care what it was nor looked like, that's a steal!   

I was contemplating just swapping the master and installing front discs.  Now that you confirmed that the brakes work fine with the drum booster, which someone else did as well, I'm going to give it a go.

[Bronzedodge]

My experience - my car originally was power drum.  i converted to 73 and up A body disc.  The pedal felt very different, hard w/ the drum booster.  Converted to the Bendix dual diaphragm- -pedal felt better, stopped better.  My drum booster may have had a problem, not sure.  I just got the Bendix dual back from Booster Dewey - it's beautiful, black semigloss.   It was $190 shipped to Maryland.  Don't but a cheap Autozone master cylinder, mine lasted 2 yrs and leaked into the booster.   

[Dino]

My experience - my car originally was power drum.  i converted to 73 and up A body disc.  The pedal felt very different, hard w/ the drum booster.  Converted to the Bendix dual diaphragm- -pedal felt better, stopped better.  My drum booster may have had a problem, not sure.  I just got the Bendix dual back from Booster Dewey - it's beautiful, black semigloss.   It was $190 shipped to Maryland.  Don't but a cheap Autozone master cylinder, mine lasted 2 yrs and leaked into the booster.   

Good to know.  What is the bore size of the master cylinder?

[jaak]

It is cheaper to buy one that's already rebuilt, especially if one from e.g., a Volare will work.

So no one here knows if other 4-bolt power boosters from the '70s are compatible?

I don't know if the Volare one will work, but Its not expensive to have one rebuilt. I sent mine to Prior Brake in Texas, cost was only $114 and that included return shipping. That was a few years back though, might cost a little more now.

Jason

[Bronzedodge]

The master cylinder I bought from NAPA is 15/16".  There's a chamfer to the bore at the end, have to measure carefully.  It was new from NAPA - no core charge, about $69.-  Can't say how it feels - not done w/ other stuff yet.

[MaximRecoil]

This is what I used for a master cylinder when I converted to disc brakes:

1976 PLYMOUTH VOLARE 5.9L 360cid V8
ACDELCO   18M57 (18M57:P)   Master Cylinder
Wholesaler Closeout - Private Label Pkg. - 30 Day Warranty   $ 11.63   $ 0.00

$11.63 from RockAuto, no core charge, and it works great. That was last summer; it looks like the '76 Volare 4-bolt master cylinder options at RockAuto are significantly more expensive now (they don't list the ACDELCO 18M57 anymore, and it seems to be $40 to $50 now on other sites). I chose one for a '76 Volare because it was specifically mentioned in Richard Ehrenberg's classic "Disc-O-Tech" article which I used as a guide for the conversion, plus it was incredibly cheap at the time:

Additionally, besides the obvious parts such as pads, wheel bearings and seals, splash shields, etc., you'll need, (only) if you now have drums, a master cylinder from virtually any '70-up disc car, even one from such common junkyard dogs as a 1976-78 F-body (Volaré/Aspen.)

http://www.moparaction.com/tech/archive/disc-main.html