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Confused about unever rear brake pad wear


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Hoping someone can help me out. I recently replaced the brake on my wife's 2011 and found the rear pads to have worn uneven from one side of the rotor to the other. The side on the piston was worn the preferentially and not parallel to the backing pad. When I took everything apart I did find one broken caliper slide (part pad slides on...not the slide pin). I also checked the slide pins which were moving free, the only thing I noticed was the vacuum/pressure effect was different from side to side. Anyway I regreased the pins and put new clips in before installing the new pads. The calipers also turned in with minimal effort. So I am kind of at a loss for what would have caused this uneven wear or why the brakes appear to be dragging now. I know the piston was pushed out far enough since it fit easily over the pads and I had to pump the pedal a few times to get them to contact. Any ideas? I am starting to think the parking brake but I would have thought if this were dragging both sides would wear not just the one. To me one side wearing over the other points to the slide pins...but they were fine.

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It sounds like you have a bad caliper that is not free to return when the line pressure is released. This would cause the pads to drag on the disk. Usually the caliper but sometimes the flexible brake lines can fail and have the same effect. If the slides and all hardware are in good working order I would be pretty certain it's the caliper.

Edited by PaulSchott
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But if it were the caliper the wear should have been more or less even when you compare the inboard pad to the outboard pad. But in my case the inboard pad had more wear which normally would point to either the pad not free to move in the carrier or the slide pins being seized. All of this seemed ok but I replaced all of the carrier clips anyway. Also both the drivers and passenger side had the same wear pattern, I guess both could have failed but wondering if it could be the parking brake since that would effect both sides and could also account for the heating I see with new pads and rotors. Just not sure how the parking brake works, would have thought this would balance the pressure across the rotor too. Maybe I should look for a parking brake adjustment just to rule it out.

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I had the exact same issue with my rear brakes. Rust had formed on the caliper bracket underneath the clips. This caused the clips to press too tightly on the brake pads causing them to not release completely. The solution was to grind away the rust on the bracket, underneath the clips, and remove an additional 5 MM of material from the bracket Liberally coat the bracket underneath the clip with anti-seize to stop future rust. This allows the pads to move more freely and not drag. I also cleaned and greased, with synthetic brake grease, the caliper slide pins and thoroughly cleaned the holes or apertures that the pins slide into.

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Fixed my brake issue.

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Most likely a combination of issues. First I have the same issue of the inboard pads wearing more on my wifes OEM brakes on her 2011 ford edge. I however do not have the same issue with my 2011 Ford Edge. Here is why: I changed my pads to Full ceramic pads and High carbon steel rotors. I also thoroughly cleaned and removed all rust from the brackets by light sanding and brushing. I have also blasted the brackets. New guide clips and ceramic CRC brake grease liberally applied to all moving contact surfaces. No abnormal wear on the rear brakes after one year and 60K miles!!!!

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The rust causes the outside pad to stick and the inboard pad is forced to move and push against the outside pad. Thus the outboard pad has less contact and friction. This also results in degraded braking. You have to check and maintain the brakes every year.

Ā 

This is how I perform brake maintenance on the 2011 Ford Edge:

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Man I am kicking myself tonight. Yesterday morning I had other projects to do outside before it got too hot and while I was working on that the wife ran out to get lunch. When she came back the brakes were a normal temp even though she went off the mountain so I figured they were fine. Then this morning she drove 40 minutes to go to the mall then back no problem. At this point I thought we were out of the woods until tonight. We drove to my mom's for dinner and while it was fine going there coming home apparently the one side got stuck again and was hot and smoking a little when we got home. Figures, now I don't have time to do this before I go to work. But I guess I will be pulling this apart again this week.

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Unless your caliper has pistons on both sides of the rotor (typically only found on higher end sports cars), the pad on the piston side will always wear out first. It will typically show tapered wear as well, more at the front, less at the back.

Ā 

If it's *really* uneven, yea you have a problem. If one looks at 20% more worn than the other, I'd call that normal.

Ā 

Edit: Greasing the slides is a good idea when the tires are rotated.

Edited by IWRBB
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Still battling this. I have taken these apart so many times to grease and check things it is pretty sad. The other day one side got really hot again when my wife drove to the mall. I left work to go see what I could do and was able to drive it home with NO heat build up issue. Last night I took them apart to check everything out again and I can find nothing. Based on mrgroupers recommendation I popped the clips out and cleaned that up but mine were surprisingly good. Since the bracket seemed good I was reluctant to grind anything away so I cleaned it and put some anti seize on it to hopefully keep it from rusting. But I did notice that the slides that clip in had markings like the pads bound up. Unfortunately I don't know if this was due to heat build up or what caused the pads to stick. Since the bracket was clean I figured it was safer to grind a little off each brake pad to get the extra clearance figuring I can buy new pads cheaper and faster than brackets. So last night I did that on the drivers side only and just regreased the passenger side. Driving to work this morning the truck felt great and I even averaged 25mpg which has never happened. So I figured I had this licked but wanted to grind a little off the passenger side too. So I did this on my lunch and took a quick spin. While the brakes didn't smoke they do seem quite hot for such a short trip. I found the rears to be hotter than the fronts, I guess maybe the vented rotors and added mass may help but seemed strange to me. I guess I will have a better idea if this grinding of the pads did anything. As a side note I took a measurement of my new pads and will compare that to my old ones tonight to see if they are slightly oversized.

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So on the truck seemed to drive fine home as well but the average MPG dropped to just under 20. This is more typical for us and I do know my other vehicle gets 2-3mpg less on the way home (slightly different route). When I got home all four wheel were more or less the same temp and I measured the old pads only to find they were 3 thousandths wider from ear to ear than the new ones. So there goes that theory that the new pads were slightly oversized. Either way two trips down and no over heating so hopefully tomorrow will be good too. If not I am taking it in for a trans flush anyway so I can have them take a look. Normally I would keep at it myself but we are about to drive from NJ to SC and don't need/want issues I don't have time to resolve.

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Another trip and no issues, some at work are starting to wonder if it is my wife's driving....I won't say that to her though. Even managed to get 27.5mpg on the way to work and confirmed on Google that the ride to work is more or less down hill so that accounts for the difference each way. Just surprised the Edge takes such a hit (6-7mpg) for only a 700ft change. Seems like a big drop over a 40 mile route.

post-15776-0-24940100-1472036258_thumb.jpg

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as far as my wife the gas and brake peddle are welded together.

Another trip and no issues, some at work are starting to wonder if it is my wife's driving....I won't say that to her though. Even managed to get 27.5mpg on the way to work and confirmed on Google that the ride to work is more or less down hill so that accounts for the difference each way. Just surprised the Edge takes such a hit (6-7mpg) for only a 700ft change. Seems like a big drop over a 40 mile route.

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