HELP!!! 1" to 1 1/4" Rotors - The 1947 - Present Chevrolet & GMC Truck Message Board Network

poolboy65-ls1 · 03-14-2007, 10:35 PM

HELP! I bought 3" drop spindles w/1 1/4 rotors already installed. Come to find out I have 1" rotors on my 81. Can I use my calipers? What do I have to do to make it work? Thanks, Mike

bigblock73 · 03-14-2007, 10:45 PM

I would assume all you have to do is buy the correct calipers. They are pretty inexpensive, about $35 a piece new from NAPA...and perhaps pads to go with them.

beaterC10 · 03-15-2007, 07:33 AM

You would have to swap bearings, rotors, and calipers when changing the spindle size. Since you already have the rotors and bearings all you need are different calipers.

You will very likely have to tweak the banjo fittings on the end of the brake hoses to get the hoses installed so you might want to also get a pair of new hoses.

poolboy65-ls1 · 03-15-2007, 10:28 PM

Have it all put together but I think the lower a arm is rubbing the rim. I have the 15X8 ralleys. Can I just grind it off?

boatpuller · 03-15-2007, 10:39 PM

that's what happened to me.a arms rubbed rally's.i tried grinding and still rubbed where ball joint is.finally said screw it,i don't want something that close to rubbing and bought some 17's.glad i did.

**N2TRUX** · 03-15-2007, 10:54 PM

You can grind the lip on the A-arm back far enough to clear the rims. This will create a weak point on the A-arm that can lead to cracking and failure. If you are anal about safety you can either box the underside of the stock A-arm or replace your rims with a narrow 15" wheel.

As mentioned, if you go to a 17" wheel the problem is resolved

03-14-2007, 10:35 PM	#1
poolboy65-ls1 iamthepoolboy! Join Date: Jun 2004 Location: Benton Arkansas Posts: 175	HELP!!! 1" to 1 1/4" Rotors (updated!) Grinding!! HELP! I bought 3" drop spindles w/1 1/4 rotors already installed. Come to find out I have 1" rotors on my 81. Can I use my calipers? What do I have to do to make it work? Thanks, Mike __________________ Black primed 81 Silverado SWB one owner rust free all original 106,000 project. Steel cowl hood, 89/91 front grill, Blazer tailgate trim, sport rear bumper, 5/6 Drop, 17" Eagle Alloys, Big block is on the stand! COMING SOON: one piece glass, and more. Last edited by poolboy65-ls1; 03-15-2007 at 10:29 PM.

03-14-2007, 10:45 PM	#2
bigblock73 yeller Join Date: Oct 2001 Location: Twin Cities Posts: 13,826	Re: HELP!!! 1" to 1 1/4" Rotors I would assume all you have to do is buy the correct calipers. They are pretty inexpensive, about $35 a piece new from NAPA...and perhaps pads to go with them. __________________ Jeff 73-87.com 73-87.com Facebook page 73-87 cab corner 6x9 speaker brackets for sale 67-72 cab corner speaker brackets for sale 47-54 cab corner speaker brackets for sale

03-15-2007, 07:33 AM	#3
beaterC10 Senior Member Join Date: Jul 2003 Location: Indianapolis, IN Posts: 1,277	Re: HELP!!! 1" to 1 1/4" Rotors You would have to swap bearings, rotors, and calipers when changing the spindle size. Since you already have the rotors and bearings all you need are different calipers. You will very likely have to tweak the banjo fittings on the end of the brake hoses to get the hoses installed so you might want to also get a pair of new hoses.

03-15-2007, 10:28 PM	#4
poolboy65-ls1 iamthepoolboy! Join Date: Jun 2004 Location: Benton Arkansas Posts: 175	Re: HELP!!! 1" to 1 1/4" Rotors Have it all put together but I think the lower a arm is rubbing the rim. I have the 15X8 ralleys. Can I just grind it off? __________________ Black primed 81 Silverado SWB one owner rust free all original 106,000 project. Steel cowl hood, 89/91 front grill, Blazer tailgate trim, sport rear bumper, 5/6 Drop, 17" Eagle Alloys, Big block is on the stand! COMING SOON: one piece glass, and more.

03-15-2007, 10:39 PM	#5
boatpuller Registered User Join Date: Sep 2005 Location: Sun City West, Az Posts: 3,822	Re: HELP!!! 1" to 1 1/4" Rotors that's what happened to me.a arms rubbed rally's.i tried grinding and still rubbed where ball joint is.finally said screw it,i don't want something that close to rubbing and bought some 17's.glad i did. __________________ " Never look up a dead dogs butt."

03-15-2007, 10:54 PM	#6
N2TRUX Happy to be here Join Date: Mar 2000 Location: Cypress, TX Posts: 39,023	Re: HELP!!! 1" to 1 1/4" Rotors You can grind the lip on the A-arm back far enough to clear the rims. This will create a weak point on the A-arm that can lead to cracking and failure. If you are anal about safety you can either box the underside of the stock A-arm or replace your rims with a narrow 15" wheel. As mentioned, if you go to a 17" wheel the problem is resolved __________________ Follow me on Facebook and Instagram @N2trux.com Articles- "Jake" the 84 to 74 crewcab "Elwood" the77_Remix 85 GMC Sierra "Scarlett" "Refining Sierra"

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