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Discussion Starter #1
A few weeks ago I noticed that I was getting an intermittent squeaking coming from my left rear brake. I didn't think much of it at first, as many brake squeaks are nothing big. A few days later I noticed it was squeaking for my entire commute home, and when I got out that brake rotor was very hot, while the other 3 were cool.
Fast forward 2 weeks as I was travelling with the Volt parked, and I finally got around to addressing the issue.
I jacked up the rear end and it was relatively difficult to turn the wheel by hand. I figured the caliper must be seized, so I went and grabbed a new caliper for about $150 at a local parts depot.

Later that night I got around to working on the car. Pulled the wheel off, and then the caliper. Before I went too far I tried spinning the hub again, and I couldn't budge it without extra leverage. The pads themselves were actually seized into the caliper bracket. I then tried to compress the rear caliper (note, a c-clamp or large pliers don't work for the rears. You need large needlenose pliers and you actually screw in the piston rather than squeeze it). It seemed to compress without too much effort, so it seemed the caliper wasn't the issue.

After spending about 10 minutes prying the pads out, I cleaned the dirt out and reinstalled everything. Then I pressed and released the brakes, and ended up with the same results. So took everything back apart, and again pried the pads out. I then took a die grinder and cleaned up and removed a tiny bit of material from one of the tabs at the end of the pads. It seems the pads were just a touch too long to fit into the bracket. After cleaning it up, and coated the tabs with antiseize and again, reassembled everything.

This time after pressing and releasing the brakes, the wheel spun freely. So now I get to return the new caliper and save myself $150! :)
 

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OEM pads or aftermarket? If it was the OEM pads I'd be concerned I hadn't found the root cause - what caused them to change shape after 5 years?
 

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Discussion Starter #3
OEM pads. I think the problem was mainly corrosion. The rust and dirt had built up and filled what little tolerance there was to begin with.
 

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I replaced my front and rear rotors, pads, and caliper guide pins today. I too noticed that one of the two pads, for each wheel, had extra "tabs" on them, basically forcing me to put that pad on the outside, and the other pad (the one with the wear bar) on the inside...which I didn't really like, but oh well.

Seems kinda weird to me to have the wear bar where you can't see it, but I guess it's a good thing that the pads "don't fit" the wrong way...so maybe the last person forced them in "backwards"?

Regardless of why, good thing you got them fixed!
 

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I replaced my front and rear rotors, pads, and caliper guide pins today. I too noticed that one of the two pads, for each wheel, had extra "tabs" on them, basically forcing me to put that pad on the outside, and the other pad (the one with the wear bar) on the inside...which I didn't really like, but oh well.

Seems kinda weird to me to have the wear bar where you can't see it, but I guess it's a good thing that the pads "don't fit" the wrong way...so maybe the last person forced them in "backwards"?

Regardless of why, good thing you got them fixed!
What replacement pads did you buy? Both my OEM and replacement Duralast Gold inner pads from Autozone are NOT interchangable with the outer, nor are they interchangeable left to right. The inner pads have a single fairly large locator pin that is supposed to align with a notch in the piston (when it's properly rotated). They also have wear indicators that only fit when they are on the proper corner of the car.
 

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Hmm, I didn’t think about the piston holes needing to be rotated to align with the pads...Maybe I should double check my stuff!

I bought WearEver platinum rotors and ceramic pads from advance auto.


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OEM pads. I think the problem was mainly corrosion. The rust and dirt had built up and filled what little tolerance there was to begin with.
Probably not coincidentally, I'm dealing with a similar problem. It seems the clock runs out on salt water brake corrosion after ~5 years. https://gm-volt.com/forum/showthread.php?326159-Rear-Brake-Issue-on-2013-Volt-Gen-1

My right rear brake was fine, the left had zero pad left. The pads were a bear to get out, I had to use drifts and hammer. Making a little extra room by grinding a bit off the tab ends has some sense to it, with a couple of reservations. 1) It's tight to start with in order to avoid chattering, but the spring seat also helps with that. 2) The bare metal exposed by grinding may result in faster future corrosion. Some carefully applied caliper grease might help.

Also, I found a procedure in the to properly tension the hand brake cable. First, release the tension, then apply. This also may play a role in brake drag.
 

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Did you also replace your brake hardware?

Went with the Carlson quiet-glide brand over OEM for all 4 brakes a couple of years ago to get rid of persistent brake squeak and haven't had a brake noise issue on my Gen1 since...
Yes, I replaced all the hardware, including new caliper guide pins and greased them up. Braking is now very smooth; my rotors were pitted very bad and hard braking I would get vibration; that has gone away completely, and there’s zero noise.


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Hmm, I didn’t think about the piston holes needing to be rotated to align with the pads...Maybe I should double check my stuff!
I would put this in the vital category. Otherwise the entire force of the piston is on the little pin(s) with unpredictable results. In case you've lost track, the wear indicators are on the inner pads and they should be "up" (in the direction of rotation) when looking at the disk.
 

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Thanks for the clarification. I actually just got done checking them and they were right, so I didn’t have to change anything. But I’m glad I double checked. Never hurts to look! :)


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Discussion Starter #12
Probably not coincidentally, I'm dealing with a similar problem. It seems the clock runs out on salt water brake corrosion after ~5 years. https://gm-volt.com/forum/showthread.php?326159-Rear-Brake-Issue-on-2013-Volt-Gen-1

My right rear brake was fine, the left had zero pad left. The pads were a bear to get out, I had to use drifts and hammer. Making a little extra room by grinding a bit off the tab ends has some sense to it, with a couple of reservations. 1) It's tight to start with in order to avoid chattering, but the spring seat also helps with that. 2) The bare metal exposed by grinding may result in faster future corrosion. Some carefully applied caliper grease might help.

Also, I found a procedure in the to properly tension the hand brake cable. First, release the tension, then apply. This also may play a role in brake drag.
I applied some anti-oxide grease to all the moving parts, and anywhere I ground the metal down.
I checked the parking break first, but it didn't seem to have any affect.
 

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Glad you posted this thread. It reminds every one that even though your brake pads can last the lifetime of the car in an EV, they still need to be inspected and cleaned to make sure they don't start hanging up from dirt and corrosion.
 

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I applied some anti-oxide grease to all the moving parts, and anywhere I ground the metal down.
I checked the parking break first, but it didn't seem to have any affect.
Okay, after taking a close look at the tab ends, I did a little grinding (bench-mounted disk sander actually, to keep the surfaces dead flat and square). The raw ends are very crude; smoothing them off likely changed the overall length very little, but should let them move more easily.
 

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Glad you posted this thread. It reminds every one that even though your brake pads can last the lifetime of the car in an EV, they still need to be inspected and cleaned to make sure they don't start hanging up from dirt and corrosion.
Indeed. Manufacturers have made enormous improvements in eliminating rust issues with car bodies. I wish they'd do the same for brake materials, for example, using stainless steel pad backing material instead of the same old pot metal you'd find on a 1970 Pinto.
 

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Discussion Starter #16
Indeed. Manufacturers have made enormous improvements in eliminating rust issues with car bodies. I wish they'd do the same for brake materials, for example, using stainless steel pad backing material instead of the same old pot metal you'd find on a 1970 Pinto.
In the average car, the pads wear out before corrosion becomes a serious issue.
 

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In the average car, the pads wear out before corrosion becomes a serious issue.
Not for the rear pads, in my experience up here in the artificially salted frozen north ...
 

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Discussion Starter #18
Well I had another issue with my rear brakes this month, this time on the other side.

I was overdue for a state inspection, so I dropped it off at a regional chain tire shop (I knew I needed 2 new tires too).
I got a call a couple hours later that my brake pads had delaminated and was hanging partially out of the caliper. They told me I would need new pads and rotors because the rotor was rusty, and possibly a new caliper.
They quoted me over $450 for pads and rotors, and another $550 if I needed a caliper (which if I let them do it, they probably would have decided was required). I declined obviously and picked up new pads and a rotor at the Autozone next door ($25 for pads and $55 for a rotor).
The outside pad on the right side was clearly the problem. The only thing holding it in was the hub of the rotor.
I carefully drove home, relying on the regen braking so I didn't risk losing the pad. At home I pulled the wheel off, and replaced the pads on both sides. The rotor just had some surface rust, so I didn't even both replacing it.
On my way back to the shop I just pulled the parking brake a few times while driving. By the time I got there the rotor looked nearly brand new.
So for 45 minutes of my time and $25 in parts, I saved $1000. Needless to say I won't be returning to this shop for inspections in the future.
 
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