1. John Kirby

    John Kirby Member

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    Jun 3, 2016
    Minneapolis , Mn
    Here's the saga of my 66 New Yorker and it's brake booster. I did look at several threads on boosters before posting here.
    30 or so years ago when I was a starving marvin and trying to keep the cruiser alive a mechanic friend mentioned a shop near where I lived had a 72 Newport they were going to send to the junkyard. It had disk brakes on it so I stopped by and talked to the guy running the shop and for $25 I could have anything I wanted off of it. It was a good deal so I jacked it up and removed the calipers, rotors and spindles along with the dual chamber master cylinder/prop valve assy. Everything bolted on my 66 and worked very well.
    20 years later as I was doing the resto I found the master cylinder had puked brake fluid into the booster. So I went online and found a cardone version that bolted in place. While doing the engine rebuild I installed a hotter cam, so a lot less vacuum for the booster. (~15" when going downhill while in low gear) Seemed to work ok while driving around the subdivision at slow speeds but I knew a vacuum pump was needed. So I finally installed one several months ago in anticipation of going to the Midwest Mopar show in Stillwater. Testing didn't go as anticipated, I needed the leg of Hercules to stop so I started looking into other options.
    Reading a few threads here I discovered cardone is to be avoided. Meanwhile I can't find a booster that is a direct replacement for the original. There are a lot of boosters for b-body cars but they all have a bracket on the back that shifts the position of the unit. Not that big of a deal if they will bolt into the same location and connect to the brake pedal properly.
    Most of them are dual chamber so they would help with disc brakes. Has anyone tried using one of these on a c body of 65-68 or so vintage? Which model is the best option and what mods are needed if it will work? The master cylinder has 4 studs for mounting.
    Seems likely these will be around for more years than our beloved c body versions. Installing new lines from the master cylinder to the prop valve is a simple task, mounting to the firewall and the pedal connection seem to be the unknown areas. Here's a photo of what is currently installed. There seems to be enough room for the b-body version. IMG_0860.JPG
  2. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    Mar 27, 2017
    Cornelius Or
    It looks like you have a single diaphragm drum booster currently installed. These do not generate nearly as much braking power as the dual units. The best booster would be a '68-71 dual diaphragm C-Body disc unit and they are getting hard to find. Most of the '72 model cars had a larger single diaphragm unit which would work on some of the older applications. The larger unit tended to not have enough clearance for the shift linkage and/or valve covers on many applications. If you had '72 unit installed to start with and it had enough clearance, you should be able to locate another one of them as they are more readily available than the dual units. The B-Body units are a smaller diameter unit and have a completely different mounting system, so they are not really an option. Many of the B-Body repops are made in China and the quality is also highly suspect. www.boosterdeweyexchange.com does a really good job of rebuilding the factory dual units and usually have a limited number of cores on hand if you can not locate the proper unit, but be advised core charges are also expensive. Cardone rebuilt units have a miserable reputation for quality control much of the time.

    You might consider putting a "Brake Booster Wanted" post up as several members have had core units for sale in the past.

    Last edited: Aug 13, 2019
    • Thanks! Thanks! x 1
  3. 73Coupe

    73Coupe Senior Member

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    Nov 12, 2014
    Belmont, CA
    Karp's Power Brake in Upland, CA may be able to help you, at least tell you the model # of a booster that'll work....

    They rebuild boosters, sleeve cylinders, etc.... not sure if they sell new parts but they are at least a good resource for all things with brakes.

    Cardone is for jamokes. Their "rebuilding" consists of cleaning and blasting the part, assembled, and maybe a quick rattle can paint job before putting into a new box with the blast media included.

    Good luck!
  4. My three 67 Polaras

    My three 67 Polaras Member

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    May 22, 2016
    I ended up using one from CPP. It is a dual diaphragm of new manufacture married to a Mopar modern master cylinder. I wanted to go that route because I was tired of the cast iron master cylinders taking a dump out their backside. They warned me on the phone it would not fit. The kit they make for C bodies only fits cars that did NOT have power brakes from the factory. Those cars had a different pedal, I think than cars with power brakes. So to refit it and eliminate the brackets that space it out from the firewall was a lot of work.
    1. I removed the firewall adapter plate and plugged the 4 holes with rosette welds that originally mounted the booster in the firewall adapter plate (the plate that stiffens the firewall). I redrilled it to the new power brake booster pattern, which is different. The new square pattern ended up centered around the big existing center hole for the pushrod. That center hole did not change any.
    2. With the firewall adapter plate redrilled to the new 3 3/8 square pattern, I then popped the two holes that go through the firewall itself common to the upper two holes of the booster. The lower two holes did not have to be redrilled through the firewall itself because those were slots, from the factory, and the bolts still slid through them. The two new upper holes are very close to the original factory holes, like binocular then. I couldn't just stick a bolt through the new hole I just drilled because the bolt will be half way on, and half way off the bottom of the brake pedal bracket that hangs on the inside of the firewall. So I had to dissect the sides of the brake pedal and mig new angles in, so that it extended way down to also pick up the bottom two holes of the booster. The factory only bolted the brake pedal at 4 locations: the two holes of the firewall mounting plate, and the two upper holes of the booster, which sit below that. Mine also picks up the two lowest holes, common to the firewall plate, the booster, (and the firewall slots). Getting those angles to fit was challenging, because they sit in a recess in the back of the firewall, and there is no leftover room.
    2. I fabricated a machined rod end to adapt their booster, without spacer brackets, to the power brake booster pedal. I don't think anyone makes one that will work. It takes a lot of measuring, and a skilled machinist.
    3. A person contemplating this needs to have a lot of confidence in their systems engineering, problem solving, and fabrication skills to make something like this work. I am not advocating going this route, making a how to, or saying this is how it should be done. This is just is how I did it. Other people have adapted these in different ways. If the original factory dual diaphragm booster was still available, and rebuilt to a high standard, I would have gone that route. Or, better yet, the aftermarket could be more attentive to our needs and make something that actually fits. From what I have seen, the aftermarket focuses a lot on the 3 3/8" square pattern, and nothing on our 4.1" x 3.25" rectangular pattern.

    1967 Polara build thread
    Last edited: Aug 14, 2019