Mopar A-Body cars often came equipped with 9" or 10" drum brakes. While these brakes might seem adequate for those people who have never driven a better-stopping vehicle before, there is much room for improvement.
A-Body slant six cars produced from 1960 to 1972 were generally equipped with drum brakes along with 13" wheels with a 4" bolt circle (BC). Since the majority of A-Bodies were equipped with the slant six engine, the majority of A-Bodies until 1973 came equipped with 9" drums on all four wheels. All A-Body drum brake vehicles use the 4" BC. In 1973 and later, some A-Body cars were equipped with disc brakes which then included 14" wheels with a 4½" BC. The type of disc brakes on the earlier cars with the 4" BC was the Kelsey Hayes (KH) disc brake, which used a 4-piston caliper. In 1973, besides changing to the 4½" BC, Chrysler switched to the single piston, slider style of caliper on A-Body vehicles. The 1970-1974 E-Body and 1970-1972 B-Body vehicles used a similar single piston caliper that instead slid on pins.
Chrysler made 3 different sets of front drum brakes for A-bodies: 9"x2½", 10"x2¼", and 10"x2½". The 9" drums were standard on all six cylinder cars from 1960-1973. The 10"x2¼" were standard on V8 cars from 1965-1972. Although Chrysler's press releases stated that 10" drums were standard equipment on all 1965 V8 Valiants and Darts, many 1965 V8's were delivered with 9" drums, The 10x2.5" brakes were standard on 1973-1975 V8 cars. Federal law mandated front disc brakes on all vehicles in 1976.
Although it might logically seem that the 10" drum brakes were similar, early 10"x2¼" brakes and the later 10"x2½" brakes do not have any common hardware. The backing plates, drums, and spindles are different between these two brakes. Nothing interchanges between these two brake systems.
Replacement parts for the early Mopar A-body cars can sometimes be hard to find. NAPA seems to have discontinued some parts, especially parts for the Kelsey-Hayes disc brakes. Centric Parts still carries a complete line of replacement brake parts for the early Mopar A-body cars.
Other general Mopar braking system information sites:
While not specific to Mopars, the following sites have some excellent braking information:
- Mopar Suspensions, Mike Martin, published by SA Design Books, 1984, ISBN 0-931472-20-2
- Mopar Chassis Modification Performance Book, Chrysler Corporation
- Performance Handling for Classic Mopars, Tom Condran, published by Faster Forge and Press, 1998
- Chrysler Performance Upgrades, Frank Adkins, published by SA Design Books, ISBN 1884089402
- How to Make Your Car Handle, Fred Puhn, published by HP Books, 1981, ISBN 0-912656-46-8
While there are many Mopar forums, the following Mopar forums have specific brake system subforums for A-Body vehicles: