Fit of rear rotor - The 1947 - Present Chevrolet & GMC Truck Message Board Network

that_ry_guy · 01-08-2015, 09:37 PM

Just received the rear disc conversion kit I ordered from Classic Industries for my 71 c10. The kit is for 71-87 GM trucks. The fit of the rotor on the axle seems really sloppy. The studs seem to be 1/2 inch and the holes are about 9/16 or 5/8. Thhe smaller holes which actually seem to be the correct diameter are I think in a 5x4.75 pattern not the 5x5 I need. I have these bushings lying around that seem to fit perfectly over the stud to make a tight fit with the rotor. I am planning on cutting them down to make 5 for each side. Anyone ever had this issue? And would my solution be appropriate?
Thanks

Number98 · 01-08-2015, 09:45 PM

Haven't seen one with that much clearance before, the kit I used from Little Shop Mfg. was a pretty tight fit, over the studs as well as with the center bore. I swapped in a new set of Dutchman axles but they have the same center as my stock axles did.

Andy4639 · 01-09-2015, 06:56 AM

Mine where from CPP. They fitted resnug. I would call them first and see what they say.

MARKDTN · 01-09-2015, 08:09 AM

I am not nearly as concerned with the studs as with the middle. Braking action will move the rotor to the edge of the studs, but if it is not centered on the middle, you will have a big imbalance. The other 2 photos show it centered much better.

that_ry_guy · 01-09-2015, 01:42 PM

Thanks guys! I have sent an email to Classic Industries explaining the fit problem. I have a feeling that the wrong rotor was included in the kit. This rear disc conversion stuff is driving me crazy. I had previously sent back another kit to another company as it turned out to be the car 12 bolt kit instead of the truck one! Learning process I guess. Hope to have it straightened up soon.

Andy4639 · 01-09-2015, 01:48 PM

Good luck with it.

The CCP kit that I used wasn't the best either. the brackets worked good. The spacers not so much. I had to make my own to get the caliper where I neded it. The hard lines on the back where the wrong size for the tee fitting had to buy adapters to make them work which it does but it's just another spot for a leak.

01-08-2015, 09:37 PM	#1
that_ry_guy Registered User Join Date: Apr 2014 Location: North Vancouver, BC Posts: 15	Fit of rear rotor Just received the rear disc conversion kit I ordered from Classic Industries for my 71 c10. The kit is for 71-87 GM trucks. The fit of the rotor on the axle seems really sloppy. The studs seem to be 1/2 inch and the holes are about 9/16 or 5/8. Thhe smaller holes which actually seem to be the correct diameter are I think in a 5x4.75 pattern not the 5x5 I need. I have these bushings lying around that seem to fit perfectly over the stud to make a tight fit with the rotor. I am planning on cutting them down to make 5 for each side. Anyone ever had this issue? And would my solution be appropriate? Thanks Attached Images

01-08-2015, 09:45 PM	#2
Number98 Prestige Worldwide Join Date: Feb 2001 Location: Worldwide Posts: 2,552	Re: Fit of rear rotor Haven't seen one with that much clearance before, the kit I used from Little Shop Mfg. was a pretty tight fit, over the studs as well as with the center bore. I swapped in a new set of Dutchman axles but they have the same center as my stock axles did. Attached Images

01-09-2015, 06:56 AM	#3
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Fit of rear rotor Mine where from CPP. They fitted resnug. I would call them first and see what they say. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

01-09-2015, 08:09 AM	#4
MARKDTN Registered User Join Date: Jan 2011 Location: Chattanooga, TN Posts: 2,171	Re: Fit of rear rotor I am not nearly as concerned with the studs as with the middle. Braking action will move the rotor to the edge of the studs, but if it is not centered on the middle, you will have a big imbalance. The other 2 photos show it centered much better. __________________ '83 K20-TPI '73 C10 '79 C10-ex-diesel(SOLD) '07 Tahoe(Son driving) '14 Suburban-DD '71 C10-current project

01-09-2015, 01:42 PM	#5
that_ry_guy Registered User Join Date: Apr 2014 Location: North Vancouver, BC Posts: 15	Re: Fit of rear rotor Thanks guys! I have sent an email to Classic Industries explaining the fit problem. I have a feeling that the wrong rotor was included in the kit. This rear disc conversion stuff is driving me crazy. I had previously sent back another kit to another company as it turned out to be the car 12 bolt kit instead of the truck one! Learning process I guess. Hope to have it straightened up soon.

01-09-2015, 01:48 PM	#6
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,945	Re: Fit of rear rotor Good luck with it. The CCP kit that I used wasn't the best either. the brackets worked good. The spacers not so much. I had to make my own to get the caliper where I neded it. The hard lines on the back where the wrong size for the tee fitting had to buy adapters to make them work which it does but it's just another spot for a leak. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.



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