Problem reinstalling new brake pads and rotor

2007 JK Sahara with 102,000 miles. I have done rear pads before on it with no issues, and i have replaced front pads and rotors before with no issues. Today i was working on putting new rotors and pads on the rear. I bought Wagner OEX pads part# OEX1274 which matches my vehicle. For the rotors i went with Brake Best Select part#780519RGS. Both of these came from O'Reillys and i verified they matched. Ii removed the entire caliper assembly from the rotor by removing the 2 18mm bolts which is what I normally due when I do pads. I had to back off the parking brake adjustment a bit to get the rotor off but no real issue there. I put the new rotor on and then depressed the piston on the caliper with a c clamp until it was completely flat. I installed both pads in the caliper and was ready to reinstall the assembly back on the rotor when I ran into an issue. The caliper assembly would not go back on. The front pad (the one that is fixed and doesnt move on the piston) was resting flush against the front of the rotor and the rear pad had plenty of clearance since I had depressed the piston fully. With that front pad flush on the rotor, the rear bracket on the assembly that has the mounting holes for the 18mm bolts would not clear the mounting bracket to get the bolt holes to line up. Its like the new pads were too thick or something. I tried every which way I could to get it back on and it just did not seem possible.

I then thought maybe the rotor they gave me wasnt the right one, so I put the old rotor back on and tried to put the caliper assembly on with the new pads and had the exact same issue. Then I thought maybe the rotor wasnt completely pushed on the hub but I couldnt see where it could be pushed on any further as the base of the wheel studs was showing flush with the holes in the rotor. After fiddling with it for an hour and cussing myself, I gave up and just put the old pads back in there as they still have a little life left and put them on the old rotors as I didnt want them on the new rotors.

What am I missing? The pads dont seem overly thick and I have used Wagner pads before. I verified I installed them correctly I just cant figure out why that caliper wont go back on. It just didnt seem possible.

Any help is appreciated and sorry for not posting pics. My hands were covered in brake dust and I didnt want to get it all over my phone.

Dumb question, but was the pad that mounts on the outside seated totally flush to the outside caliper? There is some play in that outside track it fits in.

And I know you said you pressed the piston flush, but are you positive? When I did mine a couple weeks ago, I thought I had, but I didn't.

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Sounds abnormal. Not sure what the issue is. I always put the mounting bracket on first, then put the pads in the mounting bracket against the rotor, then install the caliper into the bracket.

Wouldn't be the first time that I got the right box with the wrong parts. If the piston is flush, and old rotors don't fit, I'd say your new pads are wrong.

WJCO said:

Sounds abnormal. Not sure what the issue is. I always put the mounting bracket on first, then put the pads in the mounting bracket against the rotor, then install the caliper into the bracket.

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^^^^ this. Didn't read you were putting the pads in the caliper while it was off.

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post up a pic - I used the same brake pads and had no issues installing them

Are the calipers able to slide freely on the sliders? If they are suck on the sliders, they may be stuck in a position where the stationary pad is pushed too far toward the rotor. Good luck.

Make sure the clips that hold the pad are installed correctly. They are specific to each side. If you installed the brake pad clips into the wrong groves on the caliper it will cause the pad to sit awkwardly. I've don't it before.

^^^^ This, the clips will go in upside down and muck things up. Make sure that they are oriented correctly.

BaddestCross said:

Dumb question, but was the pad that mounts on the outside seated totally flush to the outside caliper? There is some play in that outside track it fits in.

And I know you said you pressed the piston flush, but are you positive? When I did mine a couple weeks ago, I thought I had, but I didn't.

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Yes, the outside pad is mounted flush. Checked this a couple times. And the piston is fully depressed. There is plenty of gap on the piston side between the pad and the rotor. It's on the fixed side where the problem is.

Bigjimbo said:

Wouldn't be the first time that I got the right box with the wrong parts. If the piston is flush, and old rotors don't fit, I'd say your new pads are wrong.

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I thought this too but the pads have the part number printed on the back of them and it matches the box.

BaddestCross said:

^^^^ this. Didn't read you were putting the pads in the caliper while it was off.

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I have not tried it this way but will likely be my next move. In the past I have always removed the entire bracket/caliper assembly by removing the 2 18mm bolts. Are you saying to reinstall the assembly using the 18 mm bolts then to loosen the smaller bolts on the caliper so it swings out and install the pads? Still trying to figure out how this will work if the front pad will likely not clear the rotor by doing it this way.

kpig said:

Are the calipers able to slide freely on the sliders? If they are suck on the sliders, they may be stuck in a position where the stationary pad is pushed too far toward the rotor. Good luck.

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This sounds more like what my issue is but I'm not sure how to fix it. When you say sliders are you referring to the 2 bolts that the caliper uses to mount to the bracket assembly? If so, how do I adjust that so the stationary pad is pushed back?

sipafz said:

^^^^ This, the clips will go in upside down and muck things up. Make sure that they are oriented correctly.

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Yes I made sure these were installed correctly.

puckjer said:

Yes I made sure these were installed correctly.

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You should post a picture of the issue.

puckjer said:

This sounds more like what my issue is but I'm not sure how to fix it. When you say sliders are you referring to the 2 bolts that the caliper uses to mount to the bracket assembly? If so, how do I adjust that so the stationary pad is pushed back?

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There are two sliders that connect the calipers to the mounts. The sliders should slide freely into the mounts. The calipers bolt to the sliders.

puckjer said:

I have not tried it this way but will likely be my next move. In the past I have always removed the entire bracket/caliper assembly by removing the 2 18mm bolts. Are you saying to reinstall the assembly using the 18 mm bolts then to loosen the smaller bolts on the caliper so it swings out and install the pads? Still trying to figure out how this will work if the front pad will likely not clear the rotor by doing it this way.

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Once the piston is collapsed and the whole assembly is back on, the pads will slide in when everything is mounted up. There still should be plenty of play until you step on the brake pedal to seat everything.

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ok, i think i have found the issue. i went back out and took it apart and this time removed the caliper from the bracket by using the 13 and 15mm wrenches to loosen the sliders. the bottom slider seems to move freely on the boot allowing for some play. the top slider however does not move. i have tried loosening the 15mm bolt at the end of the boot but it is super tight. the other ones looked like they had locktite on them or something. before i put more leverage on it, is the 15mm bolt a standard thread, righty tighty, lefty loosey? this bolt is what is causing the issue. it needs to slide back in as it is too far out. the bottom one moves just fine.

puckjer said:

ok, i think i have found the issue. i went back out and took it apart and this time removed the caliper from the bracket by using the 13 and 15mm wrenches to loosen the sliders. the bottom slider seems to move freely on the boot allowing for some play. the top slider however does not move. i have tried loosening the 15mm bolt at the end of the boot but it is super tight. the other ones looked like they had locktite on them or something. before i put more leverage on it, is the 15mm bolt a standard thread, righty tighty, lefty loosey? this bolt is what is causing the issue. it needs to slide back in as it is too far out. the bottom one moves just fine.
View attachment 250168

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Yes, standard threads. You might need some heat to get it loose.

sipafz said:

Yes, standard threads. You might need some heat to get it loose.

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i was able to get enough leverage to get the pin to turn but i cant seem to get it to pull out. i have tried tapping the flat part with a screwdriver and hammer and no go. i know heat was suggested. should i cut the boot off and try to apply heat to the pin part? i dont have a torch. should i go with heat gun or lighter? any other methods that could work?