The tall spindle swap for GM A-bodies
was conceived in 1987, when H-O
racing (under president Ken Crocie) pioneered this. When this swap
was performed first, there was a problem with excessive shim packs, and
the possibility of the existing A-frame hitting the steering shaft or the
headers, especially for big block Chevrolet and 455 Oldsmobile-powered
cars. More details are found at the underlined link above. Currently, Malibu
Performance has been the sole marketer of the original tall spindle conversion
parts. One of the original conceptions behind the tall spindle swap
was the availability of parts, since early A-body front disc brake assemblies
have been sought after by restorationists, or considered a rare find in
West/Advanced Suspension patented an upper A-frame that allowed the
increase in negative camber, in which the A-frame is shorter than the OEM
upper arm, and this, in fact, solved the problem with the excessive shim
*Additional information can be found
in the 3/00 issue of Car Craft.
The tall spindles
are commonly found on 1970-96 GM vehicles, and the vehicle list below,
which came with 11 or 12 inch rotors, include the following:
1970-81 F-cars (Camaro/Firebird)
1975-79 Novas (and their BOP siblings)
1973-77 A-bodies (includes A-specials)
1976-79 Cadillac Sevilles (1976
Sevilles came with 11 inch rotors)
1977-96 GM full size (except the
The spindles are 1 1/4" taller than the stock A-car
pieces, and this raises the upper control arm angle. The rotors measure
either 11 or 12 inches. Below are the parts commonly used with the tall
spindles, and GM or a wrecking yard will have the parts for swapping to
the tall spindles.
11 inch rotor conversions
If 11 inch rotors are to be used (if
anyone desires to reuse the 14 inch rallies with their classic A-bodies),
the spindles are available from GM, under P/N 14012595 and 14012596 (LH
and RH), in conjunction with the brake rotor, GM P/N 14008640, which is
common with 1979-90 full size cars, 1979 Novas (and BOP variants), and
1979-81 Camaro/Firebirds. The longer and wider outer bearing (CR Services
BR3/GM 457049) is used. Here's a generic list of the brake rotors:
The 1970-78 parts are still available,
and the spindle P/Ns are 329349 (LH) and 329350 (RH), while the rotor is
listed under GM P/N 334348. The 1973-77 GM A-bodies/1975-78 X-cars (Novas,
et.al) are a good source for 1970-78 parts, just in case if the parts are
discontinued by GM. The best spindles are those from 1977/78 models,
since these spindles are lighter, without any loss in strength ("Knuckle
Sandwich", HRM, 6/87). If coming across some 1970-77 spindles, keep
in mind that the OEM parts are most likely to be discontinued, and here's
a generic list (brake rotors) from the aftermarket:
Note: what holds true for the rotors is that the spindles
are mated to their application, and that means 11 inch spindles use 11
inch rotors, whereas 12 inch spindles use 12 inch rotors.
The 12-inch rotor/spindle combination are mostly found on the following
1977-79 Cadillac Sevilles
1977-96 GM B-cars exc. Cadillac
limousines (e.g. Fleetwood 75 - the brake rotor used is the same one used with 1971-96 Chevrolet/GMC 1/2 ton truck/vans (includes G20); some rotors produced after 1991 will have an ABS ring)
These spindles use a single piston caliper (GM P/N 18003760 and 18003761),
which are compatible with the OEM disc brake master cylinder. The part
numbers listed are for 1980-96 GM vehicles. Keep in mind that 15"diameter
wheels (or larger) must be used with these spindles, since a 14" wheel
will not clear the brake caliper.
3/16/00 update: late 1995 and all 1996 GM B-cars spindles will
have different tapers, and the only difference is a 5/8" - 18 thread, instead
of the 9/16" - 18 threads. If you end up with a late 1995/1996 steering
knuckle, one must purchase the ball joints for 1996 B-cars (the lower ball joints for 1996 B-cars is the same one used with Chevrolet Astro vans and 1977-96 Cadillac limousines), and have the
lower joint machined .080" for proper installation.
This is what is needed
for the 12-inch rotor conversion:
GM manufactures a 12 inch rotor (P/N
18016035), commonly found on 1LE Camaros (1988-92), and this rotor has
a 5 x 4.75 bolt pattern. The 1LE brake rotor is also sold as a replacement
component through parts houses. Here's the P/Ns for the 1LE rotor,
if the GM dealer is a little out of one's price range:
The matching spindles used are P/N
14012589 and 14012590 (LH and RH), which uses the longer and wider outer
wheel bearings listed under GM P/N 457049/CR Services BR3, which are wider
and longer than the old bearings traditionally used with the 1964-72 hubs
and rotors (CR services P/N A2). The inner bearings (CR Services BR6) are
the same on all GM RWDs.
The 1978/79 GM full size 12-inch
spindles will also work (because the larger wheel bearing is used), but
the 1980-96 parts are common.
The 1977 Cadillac Seville and 1977
GM full size cars of the BOP/C (Buick-Olds-Pontiac-Cadillac) and station
wagons made by all of the GM divisions used a spindle that utilized a smaller
outer wheel bearing. The rotor measured 12 inches, and a 1LE Camaro rotor
will not fit, due to the smaller bearing size. This means that the OEM
rotor should be redrilled with the 5 x 4.75 bolt pattern, and the center
hub turned when using steel rims. For starters, it's best to pirate
the 1978-96 components, since the 1LE rotor fits and functions on the later
spindle, instead of remachining a 1977 brake rotor from the salvage yard
or parts house.
There are two bolt
patterns used with the 11 and 12 inch rotors, and these are the usual characteristics:
The 5 x 4.75 bolt pattern is common
with Chevrolets and other mid-sized GM products, and most of the 11 inch
rotors use this bolt pattern. Here's a list of GMs with the 5 x 4.75
1964-88 GM intermediates
(A and G-bodies)
all model year Vettes*
1949-70 and 1977-90 Chevrolet full
size passenger cars
1962-79 Chevy II/Nova (includes
1976 Cadillac Seville
1965-70 Chevrolet/GMC full-size
all post-WWII Jaguars to mid-1990s
1982-present Chevolet S10/GMC S15/Sonoma
1982 and later vehicles will have metric
studs, instead of the 7/16" - 20 studs. The C4 Vette and Fourth Generation
F-car will have different backspacing, unlike other GMs.
The 5 x 5 bolt pattern, common with
the 12 inch rotor, is used with BOP full size vehicles to 1976, 1971-2002
Chevrolet/GMC pickups and vans (incl. Astro/Safari), 1977-79 Sevilles, and 1977-96 GM Full Size
station wagons, police cars, diesel powered vehicles, vehicles with towing
packages, and all Cadillac RWDs.
These are the parts needed to
install the tall spindles onto a 1964-72 GM A-body, and these parts can
be located at an auto parts store like Pep Boys, AutoZone, et.al:
A set of Camaro ball joints
are needed, which are (lower) TRW P/N 10277 (Moog K-6145) and (upper) 10268
The lower ball joint (TRW 10277/Moog
K-6145) must be turned .080" to fit into the 1964-72 lower A-arm,
The tie rod ends used are TRW ES2033R/Moog
ES2033RL (1964-70), and TRW/Moog ES427 (1971-72). The same part #s
are the same with the generic McQuay-Norris product line.
Note: the tie rod ends used are originally used with 1975-81
Firebirds and 1973-77 GM A-bodies (Moog ES427R), and the ES2033RL part
is originally used with 1978-88 GM A/G intermediates.
*A rebuild with Moog offset control arm shafts, in which
excessive shimming is avoided.
*Some portions of the upper control arm might have to
be trimmed, if an excessive amount of shims are needed.
*Another way to avoid a thick shim pack is to use lowered
springs, about 1 1/2 inches.
*Use the aftermarket upper arms available from Global
West of Hotchkis Performance (if anyone ends up with a set of F-car spindles
for less than $100 or for free, spend the extra $$$ for the upper A-frames!).
When using the upper arms, follow the manufacturer's instructions.