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Budget GM Rear Disc Brakes

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While old muscle cars are cool, drum brakes are not. There probably isn’t a breathed-on Camaro, Cutlass, Tempest, or Buick Special left in the world that doesn’t already have front disc brakes. But we’ve noticed that rear drums are still hanging in there. If it’s the cost involved with a $900 aftermarket conversion that has you clinging to those antiquated rear drums, we have a simple and inexpensive solution. Our pals who prowl purgatory yards have noticed that third-generation V8 Camaros and Firebirds were commonly fitted with generous rear disc brakes, 11.5-inch rear rotors and aluminum, two-piston calipers. This caliper and rotor package remained consistent between 1988 and 1997, offering a 10-year span of F-bodies from which to choose.

Upgrading your GM to Rear Disc Brakes The simplest plan is to find a rear disc brakes donor Camaro or Firebird and yank the calipers and mounting brackets. We’ve found these pieces for as little as $50 at a local yard. The rear axle bolt flange on the third-generation Camaro rear axles is the same as the older 10- and 12-bolt GM rear axlehousings, so these calipers will bolt on virtually any ’64 and later 10- or 12-bolt rear axle assembly. Replacement rotors and pads are inexpensive enough to dismiss those used pieces. A new rotor will measure around 0.790 inch thick, while minimum thickness for a used rotor is 0.720. More than likely, the caliper will be in decent shape, so all you will need is a new pair of rotors, pads, and new hydraulic hose. A new replacement hose will be metric, which will require an adapter fitting to adapt the metric hose to an existing hard line, or an aftermarket AN line can be used. The hydraulic fitting into the brake caliper is a 10mm banjo fitting, and Russell makes a straight 10mm banjo fitting with a male -3 AN fitting on the end. The fitting will use a Russell 10 mm x 1.5-inch banjo bolt and a pair of copper flat washers to seal, then you’re all but hydraulically connected.

Assuming your car is currently rolling on rear drums, it is critical to include an adjustable proportioning valve somewhere between the master cylinder and the rear calipers. This provides a way to custom tune the pressure to the rear brakes to compensate for variables such as adding rear discs, tire diameter changes, and ride height. The key is to adjust the pressure to the rear brakes to prevent premature rear brake lockup that can induce a loss of control. The only other installation issue is the parking brake cable connection that in the interest of brevity we’ll leave to you.

As for pads and rotors, there is a world of options, from basic stock replacement parts that cost almost nothing to drilled and slotted rotors and high-performance pads that are still affordable. We’ve listed a few budget rear disc brakes replacement parts, so you have no excuse not to hit the boneyard. Perhaps the biggest hassle in mounting this rear disc brake conversion on an early car is pulling the rear cover to yank the C-clips so the rear axles can be removed. The rest is easy.

Parts List

Description PN Source Price
Raybestos 11.5 replacement rotor 56407R Rock Auto $24.79
Raybestos service grade brake pad SGD413M Rock Auto 20.89
Raybestos ceramic performance pad ATD413C Rock Auto 68.79
Wilwood brake pad 15Q8482K Summit Racing 86.81
Hawk HPS pad HB112F-540 Summit Racing 67.69
Raybestos caliper seal kit WK2746 Rock Auto 8.93
Raybestos rear caliper piston DPA85167 Rock Auto 14.70
Russell 10mm banjo to -3 male fitting 640471 Summit Racing 8.95
Russell 10mm banjo bolt 640680 Summit Racing 6.99
Wilwood brake-proportioning valve 260-8419 Summit Racing 41.94

SOURCES
Rock Auto
6680 Odana Road
Madison
WI  53719
866-762-5288
http://www.rockauto.com
Wilwood Brakes
4700 Calle Bolero
Camarillo
CA  93012
805-388-1188
www.wilwood.com
Summit Racing
Akron
OH
800-230-3030
330-630-0240
http://www.summitracing.com/
Raybestos
McHenry
IL
815-363-9000
www.raybestos.com
Hawk Performance
6180 Cochran Rd.
Solon
OH  44139
800-542-0972
www.hawkperformance.com
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2 comments
ghostgta89
ghostgta89

im taking suggestions, looking to do a turbo with blow thru for small block chevy.

ubushaus
ubushaus

Cutlass, Tempest, & Buick Special all had the bearings pressed on the axle until they switched to the GM corporate rear end (197?) - they are not c-clip. Based on this article, I picked up these parts at a boneyard and am now trying to see if this will work on BOP rear ends. It will require cutting a corner off of the iron mounting bracket (leaving three mounting bolts) for the bracket to mount on the outside of the bearing retainer plate with the axle in place. I have no idea if the caliper location will match up with the rotor - we'll see. For the BOP crowd, this is not as easy as the article implies.

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