Prematurely worn out inner brake pads

[cls1989]

2019 Ford Transit Connect 2.0L, only has about 34k miles.

1. Vehicle was making a grinding sound when coming to a complete stop.

2. Discovered the inner brake pads on both the rear driver and passenger side are worn down to nothing. See photos. Photo is comparison of the worn pad vs a new one.

3. The outter rear pads had more thickness than the inner pads.

4. It appears the piston is sticking? It just seems unlikely that the rear piston would be sticking on both the driver and passenger side?

5. I turned the rear driver side piston and it turned back to its home position without much effort. With that being said, I did use one of those brake caliper compression tools, not sure if this tool would hide any type of resistance/ problem with the piston?

6. Could this be caused by something else? Stuck emergency brake?

Any help would be appreciated. Thanks

 

[Elkins45]

If your slide pins are frozen the inner pad gets pressed against the disk but the outer pad can’t move in response.

 

[ctechbob]

If your slide pins are frozen the inner pad gets pressed against the disk but the outer pad can’t move in response.

This, double-check the slider pins.

 

[cls1989]

If your slide pins are frozen the inner pad gets pressed against the disk but the outer pad can’t move in response.

Thank you. The slider pins on the rear driver side looked fine. Didn’t appear to be warped or anything like that. Sill check the passenger side tomorrow. Is there anything specific on the slider pins I should be looking for outside of warped pins? I should note that I wire brush my pins and grease when reinstalling. Maybe makes sense to just buy a new set of slider pins?

 

[DemoFly]

I've seen something very similar to this happen from TOO MUCH grease in the slide pin bore. Essentially a hydraulic lock out from full float. Can't float the caliper back towards caliper bracket and rides the inner pad.

An even coating of silicone grease is all you need.

 

[ctechbob]

How well do the pads slide inside the bracket. They should be fairly loose and easy to move.

Only other thing I can think of is that when they were installed, they moved and got stuck, which seems pretty unlikely, especially since it happened twice, or they got hung up somehow. But it would have to be a big hangup, there's a good bit of force behind a brake pad, it should at least show some wear.

 

[cls1989]

How well do the pads slide inside the bracket. They should be fairly loose and easy to move.

Only other thing I can think of is that when they were installed, they moved and got stuck, which seems pretty unlikely, especially since it happened twice, or they got hung up somehow. But it would have to be a big hangup, there's a good bit of force behind a brake pad, it should at least show some wear.

Ill check again tomorrow, but from what I can remember the old pads fit the bracket properly. At 34k miles these are the original factory brakes.

 

[ctechbob]

What do the other side pads look like?

 

[cls1989]

What do the other side pads look like?

I’ll have to get a photo tomorrow morning. From what I can recall they had some thickness to them still.

 

[Elkins45]

Thank you. The slider pins on the rear driver side looked fine. Didn’t appear to be warped or anything like that. Sill check the passenger side tomorrow. Is there anything specific on the slider pins I should be looking for outside of warped pins? I should note that I wire brush my pins and grease when reinstalling. Maybe makes sense to just buy a new set of slider pins?

You should be able to move them in and out with your hands, or at least that's been my experience with all of my vehicles.

 

[The motor guy]

Happens with my truck all the time. will have an 1/8"of pad on the outside, but will down to the metal on the inside and the slide pins end up being stuck. My truck being a diesel, hides any noise from the screechers.

 

[DemoFly]

Thank you. The slider pins on the rear driver side looked fine. Didn’t appear to be warped or anything like that. Sill check the passenger side tomorrow. Is there anything specific on the slider pins I should be looking for outside of warped pins? I should note that I wire brush my pins and grease when reinstalling. Maybe makes sense to just buy a new set of slider pins?

With the pistons still pressed in, and the pads installed, and the caliper mounted. You can manually float (slide) the caliper back and forth in the caliper bracket. Ensure it slides the full range of motion and slides uniformally.

 

[cls1989]

With the pistons still pressed in, and the pads installed, and the caliper mounted. You can manually float (slide) the caliper back and forth in the caliper bracket. Ensure it slides the full range of motion and slides uniformally.

I actually did check this. See video link below. This was the rear driver side after the piston was compressed and new pads were installed.

It doesn’t seem like it’s necessary, but it’s easy enough for me to replace both the guide pins and rubber boots with new ones. I can purchase a new set from my local auto parts store in the morning and install. Unfortunately it’ll have to be their store brand since they don’t carry OEM guide pins and boots. I would Imagine store brand should be fine?

My ultimate concern is that whatever caused the premature ware on the rear inner pads could reoccur and than the new pads will get worn done quickly / prematurely.

 

[cls1989]

Another piece of information that might be helpful. This problem was on the rear passenger side only.

After removing the caliper guide pins so I could remove the caliper from rotor and take out the old pads, I discovered the caliper wouldn’t come off. It was seized up and stuck to the rotor. I had to use a pry bar and carefully get it off. Again I still haven’t compressed the piston on the rear passenger side. I’ll do this in the morning.

 

[Lubener]

Excessively worn inner pad is from the caliper piston hanging up. I would look at the calipers themselves or the hydraulic hose feeding the calipers. Generally binding slides will cause an issue with the outer pads wearing harder.

You could have cracked open the bleeder screw on the seized caliper to see if the caliper relaxes. That would tell you if the problem is the caliper or the hose.

 

[cls1989]

What do the other side pads look like?

These are the pads for the rear driver side. As you can see there is uneven wear between the inner (bare metal) and the outter (has thickness). The rear passenger side is similar. Only difference is the inner on the passenger side has a very small amount pad material left.

 

[Mcbeem5]

Is that your rotor, it looks like it has alot of corrosion.

 

[mk378]

Yes the rotor has serious rust on the friction surface that the pads touch. That will cause uneven pad wear.

The "ring of rust" syndrome usually starts because the car is not driven often enough to rub off the light rust that normally forms from rain or dew while the car is parked outside. If the rust is thick enough, it will chew into the pad instead of the pad rubbing the rust off. Then rusting continues and increases since there is a groove worn in the pad and it will never touch the rotor in that area again. The remaining area of pad that can touch bare metal has to do all the braking. The performance of the brakes is reduced.

 

[cls1989]

Is that your rotor, it looks like it has alot of corrosion.

yes that is the rear driver side rotor (inside face). Yes there significant rust on the rust. See photo.

 

[cls1989]

Yes the rotor has serious rust on the friction surface that the pads touch. That will cause uneven pad wear.

The "ring of rust" syndrome usually starts because the car is not driven often enough to rub off the light rust that normally forms from rain or dew while the car is parked outside. If the rust is thick enough, it will chew into the pad instead of the pad rubbing the rust off. Then rusting continues and increases since there is a groove worn in the pad and it will never touch the rotor in that area again. The remaining area of pad that can touch bare metal has to do all the braking. The performance of the brakes is reduced.

So you believe the uneven bad wear / excess wear on the inner pad was caused by the rust on the surface of the rotor and not a bad piston and/or sieved guide pins?