Rear disc drag

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Baker7888

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Dec 3, 2021
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Hey guys i have a rear disc kit on my 78 malibu with 7.5 rear. The kit is identical to inline tube's kit. Anyways i have some pretty bad brake drag. I dont have wheels on yet but rotors are quite hard to turn. Any ideas? Not sure where to begin
 

Streetbu

Know it all, that doesn't
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May 22, 2011
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Did you change the proportioning valve?
 

Baker7888

G-Body Guru
Dec 3, 2021
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Did you change the proportioning valve?
I did not, only because i did a disc swap on an f body awhile ago (ws6 9 bolt rear in place of 10 bolt/drums) and all worked fine with no proportioning valve swap.

Have some people needed to shim/space the calipers? Kit came with what looks like longer spacers but no mention of these in instructions or in item checklist either …

I have not started the engine yet (still have a few things to button up) idk if this will make a difference or not.
 

abbey castro

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Oct 31, 2015
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Inline has an excellent video on you tube on installation and the use of the shims. I tired another companies' conversion kit and was never able to get the e-brakes to work. Took it off and gave it a friend to figure out. Ended doing the Camaro setup. That works great with no problems.
 

Baker7888

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Dec 3, 2021
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Inline has an excellent video on you tube on installation and the use of the shims. I tired another companies' conversion kit and was never able to get the e-brakes to work. Took it off and gave it a friend to figure out. Ended doing the Camaro setup. That works great with no problems.
Oh thanks yeah i saw the inline video but did not see them use shims. Guess ill have to watch again …

Realized by turning the yoke that there is a heavy drag spot and then it frees up some, then goes back to heavy drag. So i went back to the rotor and i can see the caliper “centering” in and out as i turn the rotor. Pads are touching the rotor at all positions. Any thoughts?
 

abbey castro

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Oct 31, 2015
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Oh thanks yeah i saw the inline video but did not see them use shims. Guess ill have to watch again …

Realized by turning the yoke that there is a heavy drag spot and then it frees up some, then goes back to heavy drag. So i went back to the rotor and i can see the caliper “centering” in and out as i turn the rotor. Pads are touching the rotor at all positions. Any thoughts?
Put it together and run it on jack stands. Let the pads wear in and see what happens. Drag on the yoke is drag from the calipers. Video has the shim install at the beginning.
 

Baker7888

G-Body Guru
Dec 3, 2021
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Maine
Put it together and run it on jack stands. Let the pads wear in and see what happens. Drag on the yoke is drag from the calipers. Video has the shim install at the beginning.
Ok yeah the pads seem very thick to me for some reason. When you said “drag on the yoke” above, I did not mean drag on the yoke—I know it is coming from the brakes. What I meant was I was using the yoke to turn the rotors easier. Any chance you could PM me a link to that video? We must be talking about two different videos. My thought is that if i was to shim, the caliper wouldn’t want to go on, as there is already contact with the outer pad as-is…

Seeing the calipers walk in and out on the slide pins as i turn the rotor almost indicates to me that the rotors are warped but i just cant imagine that is possible on brand new rotors …

Edit: I forgot to add…. I am not running or plan on running an E brake.
 
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RabbitHoleSS

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Dec 8, 2019
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Those look like my brake kit. Seville brakes. You have to use the right spacers for the housing end. Mine had 3 sizes,I just used trial and error on that(short ones worked for me). Also you have to shim the bracket from the housing end or it will warp when u tighten it down, most diffs have about 1/16" between the flange and the bearing. I bet this is your issue. My kit had 8 lock washers to be used in the kit.
 
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ssn696

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Jul 19, 2009
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Any chance the axle hubs are out of true? You could use a dial indicator to check.
 
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Baker7888

G-Body Guru
Dec 3, 2021
677
117
43
Maine
Those look like my brake kit. Seville brakes. You have to use the right spacers for the housing end. Mine had 3 sizes,I just used trial and error on that(short ones worked for me). Also you have to shim the bracket from the housing end or it will warp when u tighten it down, most diffs have about 1/16" between the flange and the bearing. I bet this is your issue. My kit had 8 lock washers to be used in the kit.
When you say shim the bracket from the housing are you referring to the backing plate delete shims?
 
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