Want to get a new power brake booster, 1973 Duster.

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timk225

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My 1973 Duster has power disc brakes with 10 inch rear drums. I've got all the parts to replace the brake system, but the vacuum booster has been tough. Advance and Autozone can't get it, Summit and Year One don't seem to have it, or at least, based on the description of what they do have, I'm not sure one will be an exact replacement for mine.

I don't care about factory appearance or correct colors, I just felt that I should replace the 51 year old booster while I'm doing the rest of the brake system.

Anyone know where to find what I need?

Here's a photo of what is in it now. This photo is before I took the excess add on junk out and the insulation off the AC lines.

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What is this booster, a Bendix series 1 or 2 or something else? I'll call that Lynwood place tomorrow.
 
That power brake booster exchange place wants $350-$400 to rebuild it. I know good brakes are important, but........

Maybe I can rebuild it myself, how hard can it be?

Are there any brand identifying marks on the booster anywhere?
 
DoctorDiff sells one if you’re not worried about matching the appearance

Bendix Style Dual Diaphragm Booster for Mopars

That said, is the booster working? Because I wouldn’t tear it down and rebuild it if it’s still working.

And of course there’s always just going manual brakes. I had power brakes in my ‘74 Duster and was very happy to replace them with a manual 15/16” master cylinder.
 
Meh, for what that thing costs, I'll just get my original rebuilt. I noticed in the description that it had what I suspected, 3 different master cylinder piston sizes. 15/16", 1-1/32", and 1-1/8". My Autozone Duralast NM1571 master cylinder is a 15/16", I guess that'll be adequate for my needs.

My booster seems to work, it has good power assist, but the internal rubber parts are old, if it isn't causing a big engine vacuum leak now, it may in the future. Under the dash panel, the previous owner installed an additional long spring to help return the brake pedal to its unapplied position, and even then sometimes it doesn't fully do it. The previous owner put a red LED light in the corner under the dash, and it lights when the brake pedal is depressed any amount. It is on a relay of course, this previous owner loved his relays. The car had a half dozen relays under the hood for the add-on cruise control and other things, we have disconnected most of them already.
 
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timk225 said:
Meh, for what that thing costs, I'll just get my original rebuilt. I noticed in the description that it had what I suspected, 3 different master cylinder piston sizes. 15/16", 1-1/32", and 1-1/8". My Autozone Duralast NM1571 master cylinder is a 15/16", I guess that'll be adequate for my needs.

My booster seems to work, it has good power assist, but the internals rubber parts are old, if it isn't causing a big engine vacuum leak now, it may in the future. Under the dash panel, the previous owner installed an additional long spring to help return the brake pedal to its unapplied position, and even then sometimes it doesn't fully do it. The previous owner put a red LED light in the corner under the dash, and it lights when the brake pedal is depressed any amount. It is on a relay of course, this previous owner loved his relays. The car had a half dozen relays under the hood for the add-on cruise control and other things, we have disconnected most of them already.
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Quality brake parts cost money, I'd much rather have that Bendix booster than some generic knock off you see with some of the kits available.

Factory master cylinder sizes for the 73+ cars were 1-1/32" or 15/16".

Honestly, if the current booster doesn't leak now I don't know why you'd mess with it. Everything fails eventually, with the quality of new/rebuild parts out there now "new" does not guarantee "good". If you have a factory service manual they lay out how to test the booster, if it works properly I'd leave it alone.
 
Well that's the thing, the brake pedal does not fully return on its own, it has an extra spring to help pull it that was clearly added in, not a factory part. That's why I think it may need rebuilt.
 
timk225 said:
Well that's the thing, the brake pedal does not fully return on its own, it has an extra spring to help pull it that was clearly added in, not a factory part. That's why I think it may need rebuilt.
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That’s more likely to be a pushrod length issue or a pedal bushing problem than a bad booster, IMO anyway
 
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