Edmond, the rear disc mods - The 1947 - Present Chevrolet & GMC Truck Message Board Network

nu2-72 · 01-22-2011, 06:46 PM

Edmond, here are the pics I said I would post on the rear discs and the explaination. I started with the factory rear end. 1972 Chevy 3/4 ton 4x4. This is the 10 bolt Eaton HO52-HO72 swap. I removed the axles. Pulled the drums and hubs. Pressed out the studs and removed everything to the flanges and cleaned. The threads were chased and while I was at this, I disassembled the entire rear end. Added a locker, ground all the burrs off the housing and chased the 3rd member and cover holes. Then it was off to the car wash with the oven cleaner and pressure washer. I had a set of backing plates from a 72 Dana front axle. These are the "U" shaped stamped plates with the tin dust shields.
The backing plates on a 1979 3/4 4x4 are full 360 degree x 1/4" stamped steel and allow for much easier machining. The Diameter is still 12.5" rotor and the axle is the 79 Corporate front axle, 10 bolt.

nu2-72 · 01-22-2011, 06:53 PM

I then measured everything and drew in ACAD. The next step was to machine the plate spacers. I added 1/4" and cut a shoulder to allow for the thickness of the plate. The spacers were machined for the 4 bolt pattern and recessed to allow the bolts to set flush. The plates were machined to match the diameter. I bolted the spacers on and rotated the plates until the bleeders were straight up. They were marked and removed. I TIG welded the front and MIG welded the backs. Rotors are assembled to the hubs and the original seal covers can be used. That is it. 76 Caddy calipers and away we go.

nu2-72 · 01-22-2011, 06:55 PM

The last thing was to disassemble, clean and paint the entire rear.

Edmond · 01-22-2011, 08:23 PM

Kevin that looks amazing. Very nice set up with the dust covers.
My rear discs are open all the way.
Do these 76 Caddy calipers have parking-brake on them?

Cya,
Edmond

nu2-72 · 01-22-2011, 10:32 PM

Yes. Missouri requires parking brakes and these use a mechanical system to do that. You can see the lever in one of the pics.

Edmond · 01-23-2011, 05:13 AM

Yep I see it now. Missed it the first time I looked.
Must have been late

Cya,
Edmond

nu2-72 · 02-14-2011, 08:26 PM

OK, I hope the pictures are good enough that you can see the details. I have TIG welded the front of the plates to the spacers. As I said, I machined a 1/4" step on the spacers for the thickness of the plates. I then chamfeped both and filled the bevel with TIG material. I then placed the plates in the lathe and MIG welded the back sides with a beautiful continous weld. Then back to the blast cabinet and on to paint. Everything has been primed and painted with Eastwood Chassis Black.

Edmond · 02-15-2011, 04:29 AM

Thanks for posting the pictures.
Your making quite some progress on the truck Kevin.
It looks like the spacer belongs there on the plate!
Just like it came originaly from the factory. My compliments!

01-22-2011, 06:46 PM	#1
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	Edmond, the rear disc mods Edmond, here are the pics I said I would post on the rear discs and the explaination. I started with the factory rear end. 1972 Chevy 3/4 ton 4x4. This is the 10 bolt Eaton HO52-HO72 swap. I removed the axles. Pulled the drums and hubs. Pressed out the studs and removed everything to the flanges and cleaned. The threads were chased and while I was at this, I disassembled the entire rear end. Added a locker, ground all the burrs off the housing and chased the 3rd member and cover holes. Then it was off to the car wash with the oven cleaner and pressure washer. I had a set of backing plates from a 72 Dana front axle. These are the "U" shaped stamped plates with the tin dust shields. The backing plates on a 1979 3/4 4x4 are full 360 degree x 1/4" stamped steel and allow for much easier machining. The Diameter is still 12.5" rotor and the axle is the 79 Corporate front axle, 10 bolt. Attached Images __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

01-22-2011, 06:53 PM	#2
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	Re: Edmond, the rear disc mods I then measured everything and drew in ACAD. The next step was to machine the plate spacers. I added 1/4" and cut a shoulder to allow for the thickness of the plate. The spacers were machined for the 4 bolt pattern and recessed to allow the bolts to set flush. The plates were machined to match the diameter. I bolted the spacers on and rotated the plates until the bleeders were straight up. They were marked and removed. I TIG welded the front and MIG welded the backs. Rotors are assembled to the hubs and the original seal covers can be used. That is it. 76 Caddy calipers and away we go. Attached Images __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

01-22-2011, 06:55 PM	#3
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	Re: Edmond, the rear disc mods The last thing was to disassemble, clean and paint the entire rear. Attached Images __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

01-22-2011, 08:23 PM	#4
Edmond Registered User Join Date: Jan 2000 Location: The Netherlands Posts: 1,063	Re: Edmond, the rear disc mods Kevin that looks amazing. Very nice set up with the dust covers. My rear discs are open all the way. Do these 76 Caddy calipers have parking-brake on them? Cya, Edmond __________________ 1971 Chevy C/20 Longhorn, 350/TH400, Edelbrock Performer, IMPCO 425 LPG Carb 1974 Chevy Camaro Z28 (Original) ------------------------- The Netherlands

01-22-2011, 10:32 PM	#5
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	Re: Edmond, the rear disc mods Yes. Missouri requires parking brakes and these use a mechanical system to do that. You can see the lever in one of the pics. __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide Last edited by nu2-72; 01-22-2011 at 10:33 PM. Reason: spelling

01-23-2011, 05:13 AM	#6
Edmond Registered User Join Date: Jan 2000 Location: The Netherlands Posts: 1,063	Re: Edmond, the rear disc mods Yep I see it now. Missed it the first time I looked. Must have been late Cya, Edmond __________________ 1971 Chevy C/20 Longhorn, 350/TH400, Edelbrock Performer, IMPCO 425 LPG Carb 1974 Chevy Camaro Z28 (Original) ------------------------- The Netherlands

02-14-2011, 08:26 PM	#7
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	Re: Edmond, the rear disc mods OK, I hope the pictures are good enough that you can see the details. I have TIG welded the front of the plates to the spacers. As I said, I machined a 1/4" step on the spacers for the thickness of the plates. I then chamfeped both and filled the bevel with TIG material. I then placed the plates in the lathe and MIG welded the back sides with a beautiful continous weld. Then back to the blast cabinet and on to paint. Everything has been primed and painted with Eastwood Chassis Black. Attached Images __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

02-15-2011, 04:29 AM	#8
Edmond Registered User Join Date: Jan 2000 Location: The Netherlands Posts: 1,063	Re: Edmond, the rear disc mods Thanks for posting the pictures. Your making quite some progress on the truck Kevin. It looks like the spacer belongs there on the plate! Just like it came originaly from the factory. My compliments! __________________ 1971 Chevy C/20 Longhorn, 350/TH400, Edelbrock Performer, IMPCO 425 LPG Carb 1974 Chevy Camaro Z28 (Original) ------------------------- The Netherlands



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