'65 Power Brake Booster Question

Brakes for your Classic Mopar

  1. dibbons

    dibbons FABO Gold Member FABO Gold Member

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    In the rear of the power booster I can spot a quarter sized flap of loose rubber around the pushrod. I believe it broke off of the main portion of some kind of rubbery seal. Is this seal important or just a dust cover of some kind?

    To replace it, is this available in the aftermarket, can we adapt another rubber thingy, fabricate something, or is it maybe included in a rebuild kit? As I understand it, the '59-'60 Cadillac models use the same booster.

    Sorry for all the fotos (the second foto is the best), it's really difficult to see back inside there. I remember having one heck of a time removing/replacing it when it was rebuilt some years back. Thank you.

    power brake rubber 1.JPG

    power brake rubber 2.JPG

    power brake rubber 3.JPG

    power brake rubber 4.JPG

    power brake rubber 5.JPG

    underhood wax 3.JPG
     
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    • Big_John

      Big_John In my defense, I was left unsupervised.

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      • Thanks! Thanks! x 1
      • dibbons

        dibbons FABO Gold Member FABO Gold Member

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        I am not sure the rubber boot recommended in post #2 is what we are discussing. The recommended boot fits a slot and my rod is obviously is round. Here is the Cadillac kit:

        Screen Shot 2020-10-11 at 1.15.52 PM.png
         
      • Big_John

        Big_John In my defense, I was left unsupervised.

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        Ahhh... You're talking about the booster and I thought you meant the seal into the firewall.

        I don't know if it's used on the Caddy too. It wouldn't surprise me.

        FWIW, if that seal in the back of the booster is shot, that means all the internal rubber is probably bad too. I suggest sending it out to Booster Dewey for a rebuild. They did mine and it works great.
        Power Brake Booster Exchange | Providing Parts for Classic Cars
         
      • 65 Dartman

        65 Dartman FABO Gold Member FABO Gold Member

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        I believe Ulf @65dartcharger researched this and found those late 50’s Caddys used the same booster. Maybe he’ll chime in on that and your issue on the torn rubber.

        Agree with @Big_John on his evaluation of the internal booster rubber parts and sending it to Booster Dewey to get rebuilt.

        I assume you have the vacuum storage tank that is required with that booster?
         
      • dibbons

        dibbons FABO Gold Member FABO Gold Member

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        Yes, I have the storage tank.

        OK, I removed the booster (it was rebuilt about ten years ago) and I think we are in luck. It looks like the rubber seal (the size of a quarter) was a remnant of an old, previous seal. The back of the booster has a complete seal still in place (although it feels "hard" and I can see mini-cracks on the surface).

        The firewall seal with the slot for the brake pedal (has white overspray on it) is in place but has seen better days. This seal is not critical to the booster functioning as I see it only isolates the engine compartment from the passenger compartment (not 100% perfectly airtight even when new).

        brake booster removed 2.JPG

        brake booster removed 3.JPG
         
        Last edited: Oct 11, 2020
      • dibbons

        dibbons FABO Gold Member FABO Gold Member

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        I am just going to clean and paint my booster for now and put it back on. Here is a Dodge kit and another Cadillac kit for future reference:

        Screen Shot 2020-10-11 at 2.56.12 PM.png

        Screen Shot 2020-10-11 at 2.58.28 PM.png
         
      • cudamark

        cudamark FABO Gold Member FABO Gold Member

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        I never did like those Bendix boosters with the remote reservoir. They were always trouble prone on the cars I had with them. I'd rather go manual than power anyway. More room to work in the engine bay.
         
      • BillGrissom

        BillGrissom Well-Known Member

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        The Midland-Ross boosters are easier to take apart than the Bendix, but I haven't seen rebuild kits. They also changed the style between 1965 and 1974, as I had 2 which externally appeared similar, one from my 1965 C-body and another from a 1974 Dart. I tried to swap the rear plates to get the bolt pattern for my 1965 booster but the sliding input cylinders were different diameters. The reason was that the 1965 diaphragm had a hole where the rubber was brittle at port, probably due to gas fumes from engine though I had an inline charcoal filter. If I could buy just the diaphragm plate, that would be great, but nada.

        One idea is to use a much later booster as I did in my 1965 Dart which came w/ no booster (drum brakes) and I wanted one for eventual disk brakes. I installed the firewall brackets and lever from the 1974 Dart and bolted a booster from a 1990's Intrepid. I had to rat-tail file the mounting holes slightly to fit it. I also recall adding a bushing for the larger hole on the input rod, at the lever. That let me use any modern 2-bolt master cylinder. Instead of the one from the Intrepid (slanted reservoir), I used one for a 1990's Breeze w' ABS (2 ports). You can see it in my avatar.
         
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