Uneven Pad Wear Rear Discs

PC

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#1
Make
Ford
Model
Fusion
Year
2012
Miles
61000
Engine
4 cyl.
Have a 2012 Ford Fusion, rear outboard pads worn out, inboard pads still serviceable. Replaced pads, clips and rotors,cleaned and lubricated sliders, pistons turned in nice and easy. Now less that 10,000 mi, outboard pads show noticeable wear and inboard pads look fine. Parking brake applies and releases, doesn't stick. I don't want to throw more pads and rotors at it if something is going on. Strange that the outboard pads wear before the inboard pads. Any ideas?
 

jd

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#2
My first blush reactions are: Something Hydraulic:

Sticky Caliper Pistons
Restrictive Rear Brake Hose(s)
Clogged Compensation Port in Master Cylinder

Which Engine? Might determine different brakes.

Rear Disc is Parking Brake, too, Correct? Were you able to retract those parking brake ratchets when you did pads? Doesn't sound like it might be the problem, mostly curious.
 

jd

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#3
Sorry... saw "4-cyl" and looked the calipers back up on RockAuto.com. Those look like parking brake ratchets in the rear pistons too. Curiosity satisfied.

Still suspect Hydraulic. Noticed it has a flex hose to each caliper. Are they clamped with steel guides anyplace, that might be rusted and pinching the hoses? The usual problem with hoses is the liner fails, and collapses. This creates somewhat of a check valve. Pedal pressure can apply the brakes, but not all pressure is relieved when the brake is released.

For that matter, make sure your brake pedal IS returning all the way to full release.
 

PC

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#4
Restriction a possibility, but BOTH rear discs and if so, shouldn't the inboard wear first if the piston exerts a bit of pressure on the pad. The original outboard pads were down to the metal while the inboard pads were still serviceable. I wonder how these rear calipers self-adjust and does the parking brake play a role with self adjustment. Could that parking brake contraption keep the caliper from releasing? Don't know. I watched while a helper operated the parking brake and that lever moves and the rotor turns when released. I even thought software sending more pressure to the rear brakes, but even then BOTH pads should wear evenly. Have another set of pads and rotors waiting to install.
 

nickb2

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#5
Only thing that can cause this are guide pins.

Sherlock holmes theory needs to be applied here.

Most likely, the guide pins are loose or seized in the guide holes allocated for this.

Best way to fix this is with a complete loaded kit.

There are three major components to a caliper kit. The caliper itselfs which drives pistons to apply hydraulic pressure. Those must be free to travel to allow freeplay and NO brake drag. Same thing for the guide pins. They must allow for the caliper to move freely once hydraulic pressure is released. Then come the anchor for the pads. If those are sticking due to rust or grime buildup, one or more pad wear situations may occur. Uneven or tapered wear. In some cases, guides pins will do the same.

Never will a caliper drive an outboard pad to wear put before the inbourd if it is working in conjunction with the rest of the loaded system.

My guess, guide pins are shot. They are working off axis, binding to the stage were the caliper will release pressure on inboard, but out is always in friction mode.

https://www.autozone.com/brakes-and-traction-control/brake-caliper-rear/ford/fusion/2012

AT least we know you have discs and pads. Although, you might want to consider some premium pads. Screenshot (218).png
 
Last edited:

nickb2

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#6
Of note also, on these models, resembles volkswagen, bmw and other such shyte system. If the spring loader for out board pads was forced or broke, or just not installed, will cause outboard wear because it is causing off axis motion. This has nothing to do with proper working pistons, slides or guide pins. That is why a loaded kit takes all the guess work out of it, They come loaded. I prefer the semi metallic ones, they even come with the pads pre installed. ;)

That way you don't look like an idiot taking your wheels off every other week installing some organic crap and blaming the high heavens for lack of tooling or even just not knowing how to hook up a dial indicator to see the axial off play when hydraulic pressure applied. That is why the engineers of this system invented this beauty.

It is usually called a outboard pad retainer clip. Or something to that bull my french translation does not want to translate, Should look something like this. When these are not installed right, all kinds of things go wrong. ESPECIALLY OFF AXIS GUIDE PIN WEAR. Remember, the actual contact of the anchor to guide pin surface on this model is no more than one inch. Most models have at least 2 1/2 to 3 inch of guide pin contact and WAY less axial play. That is why this retainer is all important and way overlooked. Especially since for the un initiated, they are a bitch to take off and re install without distorting the shyster out of them and hence rendering them useless.

2010-01-08_033135_06_Focus_Front_Disc_Rattle_clip.jpg
 
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big al

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#7
Ill thtow in my $.02 here, did a rear brake job on a fusion a while back. Lucky for me it was a friend and not a paying customer. I was kinda lax as i was doing it, got the brake job done and they were good. Some thousands of miles later he calls and says the brakes on the ford are grinding. Come on over ill have a look. Outside pads gone (metal to metal) inside pad still usable but also worn. After giving it more attention it was my fault. Here what happened- - after turning in the caliper piston i did not line up the notches on the piston with the tits on the brake pads. So i did the job again this time paying more attention, lined up the notches in the caliper piston with the tits on the pads. Everything went very well, and i havent touched the rear brakes on that car in 2 years. The problem was when the brakes were applied it put an extreme amount of pressure on the outside pad while the piston continued to adjust accordingly. NOW im not sure if your fusion is the same but this is something youll want to check.
 

nickb2

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#8
I remember installing rebuilt crap like this, the caliper guides were so worn, they would install nylon sleeves to take up the guide pin play and sell those shyte kits for "new and improved". Mazda was pretty strong on that crap.

You have the same system on your fusion. Just a mazda in disguise.
 

nickb2

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#9
Here what happened- - after turning in the caliper piston i did not line up the notches on the piston with the tits on the brake pads
Yes, and yes again, that also is a beginner mistake. . I completely forgot about that, cuz I am so used to aligning those up now due to my own noob mistakes of past, it just is second nature now. A huge thx for pointing that out. Might help OP to get satisfaction.

Thx Big al for being honest.
;)
 

big al

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#11
Lol, yeah ive done many brake jobs but just got a little lax,lazy,cocky whatever you wanna call it. Always gotta be on your A game with the crap now adays. Yes a beginner mistake for someone whos been turning wrenches for very long time. Hopefully hell let us know what the outcome was. Its good being able to help people.
 

nickb2

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#12
@ big al, you will notice in the snapshot I provided, the engineers actually put a notch in the anchor plate to line up the divets for the "tits of the pads.

Look closely, I will snap shot that again. With my fine art of whatever.

Screenshot (218).png Screenshot (220).png
 

big al

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#14
Doing well, still going. No other way to go. Looking foward to getting my 1951 chevy custom car for some play, my son has already played with his 469 cubic inch trans am. It fun playing with the old stuff sometimes.
 

jd

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#15
Uh Uh... Does Honda Accord EX V6 2005, have tits on its rear pads? If so, I have a sister's car to take back apart. Odd, since over my lifetime, I've gotten more trouble concentrating ON those things, not overlooking them.