9" drum to disc conversion confusion
taken from one of the articles in my previous post:
'62-'72 A-BODIES (Dart, Duster, etc.)
If your car now has 9-inch drums, the first step up would be the 10" drums used on all '65-up 8-cyl cars. We frankly wouldn't drive an A-body over 40 mph with the 9-inch drums, for reasons having nothing to do with the brakes. The small ball-joint-to- knuckle bolts, which are loaded in shear, are known to snap, usually at the most inopportune time.
The 10-inch, 65-72 drums are a simple R&R bolt-on. You'll need a set of the 10" drum ball joints and the aforementioned larger bolts, of course. The next step up, incrementally, would be to use the factory 4-piston Kelsey-Hayes setup. This has the advantage (or disadvantage, depending on your point of view) of keeping the weird 4-inch bolt circle hubs. If you go this route, you'll still need to swap master cylinders and add a proportioning valve as we outlined in the main text. But these brakes arent cheap or common anymore, and are prone to piston siezing if left unattended for any length of time.
The ultimate swap would be the unicast rotors (either size) as outlined above. To do this, you'd need everything in our parts list plus a pair of upper control arms and all four ball joints from a '73-'76 disc-brake A-car. For factory sway-bar cars, the same caveats apply to the A-bodies as we outlined in the main text for the late-sixties B-cars. But then youll have brakes up the yazoo. Incidentally, this is what stops the famous Mopar Action Green Brick.
'73-'76 A-BODIES
These cars came in two flavors, drum and disc, with the drum cars being similar to the '72-down cars (see above), with the main difference being the use of the larger 73-up B/E-body inner wheel bearing. The disc-equipped cars already have unicast rotors, but they used slider-type calipers. The cheapo upgrade is just swap to semi-metallic pads (slider type) and be happy. You can also use the 11.75- inch rotors and yet keep your slider setup by simply using caliper adapters from a '76-up slider- equipped B-body (these were typical on the 2-door versions such as Cordobas). You can also go all the way to the less-likely-to- stick pin-type calipers. For this, just use the adapters on our parts list, along with pin calipers from a '73-up B-body. This is handy because the '73-up calipers use the same hollow banjo-bolt hose attachment method as the original slider calipers, and you'll be able to retain your original hoses.
'73-'75 B-BODIES (Charger, Satellite, etc.)
These cars are also factory equipped with unicast rotors, but they came with pin-type calipers. A change to the larger rotors requires only a simple adapter change (to the ones shown on the parts list) and nothing more. No knuckle or caliper swap is required. The calipers on these cars mount toward the rear of the car.
'76-UP B-BODIES (Cordoba, Fury, etc.)and 79-up R-BODIES (St. Regis, etc.)
This group obviously already has the big rotors, etc., as these are the primary donor" cars for our swap. For H.D. runnin', though, be sure you've got the reinforced rotors and semimetallic pads, and you're ready to rock and roll. Cars equipped with slider calipers may, if desired, be converted to the K-H pin style via an adapter swap. Use the '73-up calipers (banjo-bolt hose type,) of course.
F-BODIES and SPINOFFS (Aspen, Mirada, Diplomat, etc.)
We're referring here to all Volarés, Aspens, Miradas, Diplomats, etc. These cars use the 10.87" unicast rotors and slider calipers. As we mentioned under the later-A-body heading, you can swap up to the 11.75" rotors by simply changing to the appropriate adapters. A changeover to pin-type calipers, if desired, also requires only an adapter change, being certain to use the '73-up style pin-type calipers.
65-73 C-BODIES
Early disc-equipped incarnations of these cars used Budd 4-piston brakes, later models had K-H pin type calipers. The K-H brakes are huge (1¼" thick), in fact, they are more closely related to D-truck and B-van brakes than they are to any other Mopar passenger car. C-body disc brakes can't swap to/from any other Mopar passcars, and vice-versa. They are, literally, a class by themselves.
Along with the rest of Chryslers models, C-bodies went to 1- piece unicast rotors in 1973 (actually, C-bodies made the sap in late '72). This necessitated a knuckle redesign. The result is simple: for good, lowbuck brakes, with ready parts availability, you need to find a junked (or parked, if youre quick) 1973 (or late '72) disc-equipped C-cruiser, and take everything (incl. rotors, calipers, knuckles, hoses, adapters, etc.) You wont need the control arms, since they are identical from 1965 thru 73. For cars now equipped with 4-piston brakes, you will, however, need to swap the lower ball joints; but this is a blessing in disguise: The needed ball joints are way more common (read: cheaper!)
Another option for C-bodies is the Scarebird kit, see Mopar Action's December, 2009 issue. This uses stock drum knuckles, lowbuck custom adapter brackets, and a clever mix of parts-store components.
Under the "F" bodies part you'll see some Aspen info on brake rotors and calipers.
Treblig in tex
