The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post

*Shane* · 03-21-2001, 08:25 PM

72BBGMC,

I opened up the backing plate center hole on a Bridgeport mill, with a boring head. Once i had the center hole bored out, I re-drilled the mounting holes. Most machine shops should be able to do this for you. You need to make them a sketch with the dimensions of the bored hole and the position of the new drilled holes. Better yet, take your old backing plate (drum brake baking plates) with you and tell them to use that as a reference for your modifications. You will also have to have the axles turned to fit the rotors too. I suggest buying new rotors and take them to the machine shop, so the machinist has something to use as a reference. If you cant find anyone to do this for you, email me, i may be able to work something out for you.

I cut the "pie-shaped" section with a "Zizz" wheel, or however ya spell it. I made sure that i had at least 2 bolts opposite the rotation of the wheel/tire. This is to counter act the torque placed on the backing plate when the brakes are appplied. With the Caddy setup, the passenger side caliper is mounted on the the rear of the axle and the drivers side caliper is mounted on the front of the axle. On the passenger side, i cut it so that the top of the backing plate has two bolts in it and the bottom has one, where as the drivers side, the plate has the two bolts on the bottom and only one bolt on the top.

I got the idea of only using 3 bolts and mounting on the back of the flange from the aftermarket kits you can buy for the Chevy 12 bolt rear end. They use Caddy calipers and Caddy rotors, which you can buy at your local parts place. What your paying the extra money for is the brackets that they have designed and made. Their brackets are 2 piece and only use 3 of the 4 bolts on the axle flange.

I had to mount the backing plate on the back side of the flange in order to get the correct spacing. With the bracket mounted on the front of the flange, the caliper would not line up with the rotor and the backing plate. Once placing it on the back of the flange, it lined up perfectly.

I hope to have you guys some pics this weekend. Hope this explanation helps out some.

------------------
Keep On Truckin'

Shane
nduroracer@aol.com

[This message has been edited by Shane (edited 03-21-2001).]

03-21-2001, 08:25 PM	#11
Shane Account Suspended Join Date: Jun 2000 Location: over yonder Posts: 14,270	72BBGMC, I opened up the backing plate center hole on a Bridgeport mill, with a boring head. Once i had the center hole bored out, I re-drilled the mounting holes. Most machine shops should be able to do this for you. You need to make them a sketch with the dimensions of the bored hole and the position of the new drilled holes. Better yet, take your old backing plate (drum brake baking plates) with you and tell them to use that as a reference for your modifications. You will also have to have the axles turned to fit the rotors too. I suggest buying new rotors and take them to the machine shop, so the machinist has something to use as a reference. If you cant find anyone to do this for you, email me, i may be able to work something out for you. I cut the "pie-shaped" section with a "Zizz" wheel, or however ya spell it. I made sure that i had at least 2 bolts opposite the rotation of the wheel/tire. This is to counter act the torque placed on the backing plate when the brakes are appplied. With the Caddy setup, the passenger side caliper is mounted on the the rear of the axle and the drivers side caliper is mounted on the front of the axle. On the passenger side, i cut it so that the top of the backing plate has two bolts in it and the bottom has one, where as the drivers side, the plate has the two bolts on the bottom and only one bolt on the top. I got the idea of only using 3 bolts and mounting on the back of the flange from the aftermarket kits you can buy for the Chevy 12 bolt rear end. They use Caddy calipers and Caddy rotors, which you can buy at your local parts place. What your paying the extra money for is the brackets that they have designed and made. Their brackets are 2 piece and only use 3 of the 4 bolts on the axle flange. I had to mount the backing plate on the back side of the flange in order to get the correct spacing. With the bracket mounted on the front of the flange, the caliper would not line up with the rotor and the backing plate. Once placing it on the back of the flange, it lined up perfectly. I hope to have you guys some pics this weekend. Hope this explanation helps out some. ------------------ Keep On Truckin' Shane nduroracer@aol.com [This message has been edited by Shane (edited 03-21-2001).]