pauls340
Well-Known Member
I have a new set of 9.09" x 1.75 drums with 4" sbp that I got for a 67 cuda but what other cars will they fit? I don't need them any longer. pm me if you will [email protected]
9" Drums were on what cars
- Thread starter pauls340
- Start date
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mikedevore
Well-Known Member
I Would Say All Slant 6 Cars, As Well Base V-8 Cars.
swing69
fightin' socialism
From autohobby digest:
Most A-bodies came with slant six engines and as a result, most A-bodies came with the minimum requirement of brakes: 9" drums on all four wheels. These are barely adequate for slant six cars, but should be considered unacceptable for V8 cars (1964 V8 A-bodies, despite coming equipped from the factory with 9" drum brakes, should be outfitted with something beefier). There are a lot of possible swaps, below is a description of all of the factory A-body brake systems and their similarities in components (ball-joints, spindles, etc).
Chrysler made 3 different sets of front drum brakes for A-bodies: 9x2.5", 10x2.25", and 10x2.50". The 9" drums were standard on all six cylinder cars from 1963-1975 (see footnote #1). The 10x2.25" were standard on V8 cars from 1965-1972 (some 1965 model V8's came with 9" drums, although it was not Chrysler's original intention. It was stated in press releases that ALL 1965 V8 Valiants and Darts would be equipped with 10" drums, however some early year V8 cars came though with the 9" drums). The 10x2.50" brakes were standard on 1973-1975 V8 cars.
All A-body drum brake cars were small bolt pattern!. From 1973 to 1975, A-bodies with drums used the small bolt pattern (5x4"), while the disc brake cars used the large bolt pattern.
To make the distinction, early 10x2.25" brakes and the later 10x2.5" brakes do not share backing plates (see footnote #2), drums or shoes. You cannot mix and match parts between these brake systems. Note the photograph below and the different appearances of the two 10" drums.
All three brake systems offered on A-bodies from 1963-1972 used the exact same suspension geometry. The significant difference between the 9" drum, the 10x2.25" drum, and the 11" Kelsey-Hayes discs were the spindles. Otherwise, all three brake systems share the same suspension components including upper control arms (UCA), lower control arms, brake strut rods, tie-rods, shocks, and ball joints. The only exception is the lower ball joint on the disc brake cars. The disc brake lower ball joint is a heavy duty version of the drum ball joint.
When rebuilding a drum front end, with a rebuild kit from PST, for example, one can opt for the 1966-1972 disc brake rebuild kit. This kit is identical to the drum brake kit except that it comes with a heavy duty lower ball joint. There is an expection, there are two holes that accept the large bolts that fasten the ball joint to the spindle. On some ball joints, these holes are threaded and on some, they are not (the author can't remember which years are which..)
To upgrade from 9"s to 10x2.25"s only the spindle and all the brake hardware (backing plate to drum) need be swapped. To upgrade 9" (or 10x2.25" drums) to the KH 4-piston discs, you'll need spindles and the heavier duty lower ball joints (using the drum brake lower ball joint would probably lead to premature ball joint failure).
For 1973-1976, 9" drums were available as standard brakes for six cylinder cars. This front end (drums, ball jounts, spindles) was more or less the same that had been used from 1963.
In 1973, for 10" drum and disc brake A-bodies, the front suspension and brakes were changed considerably. The new 10x2.5" drum brake system was introduced as well as the new unicast 11" disc rotor system (this disc system was standardized across the board for all A,B,C and E bodies in 1973). The A-body 10x2.5" drum and the new unicast discs shared the same UCA, and upper and lower ball joints. These are the same ball joints used on 1962-1972 B-bodies and 1970-1974 E-bodies. The A-body UCA is not shared with the B-bodies or E-bodies. Although the suspension geometry is the same of 1973-1976 A-bodies and 1963-1972 A-bodies, since the upper ball joint changed, the 1973-1976 UCA for 10x2.5" drum and disc cars is different than the 1963-1972 A-body UCA.
The 10x2.5" brake system was actually adopted from the 1962-1972 B-body 10x2.5" drum system, however there were several running changes in bearing diameter, wheel cylinders, and hold down kits that make interchange non-existent between the B-body 10" drums and the 1973-1976 A-body 10" drums.
The 1973-1976 A-bodies disc brakes are significantly different than the early disc brakes. In 1973, Chrysler adopted the Chrysler built "unicast" rotor across the board on all A/B/C/E-body and D-100 truck applications. This marked the end of the the four piston calipers and two piece rotors used in previous years. The "unicast" rotors were so-named because they incorporated a single casting of the rotor and hub where previous disc setups used a separate hub and rotor design.
Later in the 1970s and early 1980s, some large C-body, B-body, and R-body cars came with 11.75" rotors. These can be installed on any 1973 and later unicast rotor disc spindle if the proper caliper adapters need to be used along with 15" rims (stock 14" rims don't fit!).
One Additional note: the 1973 A-body 10x2.50"s used a finned drum, that might not accept the early factory steel rims or aftermarket rims made prior to these brakes. My American Racing slot mags fell prey to this change and can only be used with 1964-1972 small bolt pattern hubs.
Most A-bodies came with slant six engines and as a result, most A-bodies came with the minimum requirement of brakes: 9" drums on all four wheels. These are barely adequate for slant six cars, but should be considered unacceptable for V8 cars (1964 V8 A-bodies, despite coming equipped from the factory with 9" drum brakes, should be outfitted with something beefier). There are a lot of possible swaps, below is a description of all of the factory A-body brake systems and their similarities in components (ball-joints, spindles, etc).
Chrysler made 3 different sets of front drum brakes for A-bodies: 9x2.5", 10x2.25", and 10x2.50". The 9" drums were standard on all six cylinder cars from 1963-1975 (see footnote #1). The 10x2.25" were standard on V8 cars from 1965-1972 (some 1965 model V8's came with 9" drums, although it was not Chrysler's original intention. It was stated in press releases that ALL 1965 V8 Valiants and Darts would be equipped with 10" drums, however some early year V8 cars came though with the 9" drums). The 10x2.50" brakes were standard on 1973-1975 V8 cars.
All A-body drum brake cars were small bolt pattern!. From 1973 to 1975, A-bodies with drums used the small bolt pattern (5x4"), while the disc brake cars used the large bolt pattern.
To make the distinction, early 10x2.25" brakes and the later 10x2.5" brakes do not share backing plates (see footnote #2), drums or shoes. You cannot mix and match parts between these brake systems. Note the photograph below and the different appearances of the two 10" drums.
All three brake systems offered on A-bodies from 1963-1972 used the exact same suspension geometry. The significant difference between the 9" drum, the 10x2.25" drum, and the 11" Kelsey-Hayes discs were the spindles. Otherwise, all three brake systems share the same suspension components including upper control arms (UCA), lower control arms, brake strut rods, tie-rods, shocks, and ball joints. The only exception is the lower ball joint on the disc brake cars. The disc brake lower ball joint is a heavy duty version of the drum ball joint.
When rebuilding a drum front end, with a rebuild kit from PST, for example, one can opt for the 1966-1972 disc brake rebuild kit. This kit is identical to the drum brake kit except that it comes with a heavy duty lower ball joint. There is an expection, there are two holes that accept the large bolts that fasten the ball joint to the spindle. On some ball joints, these holes are threaded and on some, they are not (the author can't remember which years are which..)
To upgrade from 9"s to 10x2.25"s only the spindle and all the brake hardware (backing plate to drum) need be swapped. To upgrade 9" (or 10x2.25" drums) to the KH 4-piston discs, you'll need spindles and the heavier duty lower ball joints (using the drum brake lower ball joint would probably lead to premature ball joint failure).
For 1973-1976, 9" drums were available as standard brakes for six cylinder cars. This front end (drums, ball jounts, spindles) was more or less the same that had been used from 1963.
In 1973, for 10" drum and disc brake A-bodies, the front suspension and brakes were changed considerably. The new 10x2.5" drum brake system was introduced as well as the new unicast 11" disc rotor system (this disc system was standardized across the board for all A,B,C and E bodies in 1973). The A-body 10x2.5" drum and the new unicast discs shared the same UCA, and upper and lower ball joints. These are the same ball joints used on 1962-1972 B-bodies and 1970-1974 E-bodies. The A-body UCA is not shared with the B-bodies or E-bodies. Although the suspension geometry is the same of 1973-1976 A-bodies and 1963-1972 A-bodies, since the upper ball joint changed, the 1973-1976 UCA for 10x2.5" drum and disc cars is different than the 1963-1972 A-body UCA.
The 10x2.5" brake system was actually adopted from the 1962-1972 B-body 10x2.5" drum system, however there were several running changes in bearing diameter, wheel cylinders, and hold down kits that make interchange non-existent between the B-body 10" drums and the 1973-1976 A-body 10" drums.
The 1973-1976 A-bodies disc brakes are significantly different than the early disc brakes. In 1973, Chrysler adopted the Chrysler built "unicast" rotor across the board on all A/B/C/E-body and D-100 truck applications. This marked the end of the the four piston calipers and two piece rotors used in previous years. The "unicast" rotors were so-named because they incorporated a single casting of the rotor and hub where previous disc setups used a separate hub and rotor design.
Later in the 1970s and early 1980s, some large C-body, B-body, and R-body cars came with 11.75" rotors. These can be installed on any 1973 and later unicast rotor disc spindle if the proper caliper adapters need to be used along with 15" rims (stock 14" rims don't fit!).
One Additional note: the 1973 A-body 10x2.50"s used a finned drum, that might not accept the early factory steel rims or aftermarket rims made prior to these brakes. My American Racing slot mags fell prey to this change and can only be used with 1964-1972 small bolt pattern hubs.
junkaholic
Member
WOW! lot of good information, well put.
tyler_s18
k-member
where is the 9" measurement taken? is it i.d. or o.d. and if its o.d. where lol?
swing69
fightin' socialism
9" is an ID of the braking surface. max dia. after machining is 9.090.
Sometime, places spec the drum by OD., that's just weird, but thats' the way its done on some RockAuto listings.
Sometime, places spec the drum by OD., that's just weird, but thats' the way its done on some RockAuto listings.
tyler_s18
k-member
ok. so my 75 scamp with the 8 1/4 has 10" drums so they do not fit
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