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Uneven brake pad wear, no pulling?

04 Subaru Impreza 2.5 TS (Make/model drop downs weren’t working on my phone)

Was checking out brakes and discovered that on the rear axle, driver side pads were worn all the way down while passenger pads still had about 2/3 pad left.

However, my car does not pull when braking. Assuming both sets of pads were installed at the same time, what could be the cause of this?

The rear brakes don’t do much. Can you safely drive at speed and then apply and release the hand brake? That will take the front brakes out of the scenario. You might feel some pull then.

Usual cause is rusted “frozen” piston in the brake caliper.


Concur, calipers the most likely suspect

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I agree that the caliper is the likely culprit here, but if you replace the caliper…also replace the flexible hose at that caliper.
These hoses deteriorate with time and break down from the inside…causing the hose to act like a check valve and not allowing the fluid to return from the caliper… and at 14 years you are at that point.



Could be stuck piston, but could very well be sticky slides where pads are supposed to travel. If one pad is worn unevenly or worn more than its mate, stuck pads are most likely the problem. Either way, a proper brake job will correct the problem. Unless it is the brake line as mentioned by Yosemite. Some technicians, in a hurry will miss that. Then you’ll be back for another brake job soon.

replacing caliper and hose is one option

another option is to reassemble calipers on your own:,2004,impreza,2.5l+h4+turbocharged,1428791,brake+&+wheel+hub,caliper+repair+kit,1720

hoses are to be replaced too

Concur. The pads should wear more evenly than that, even on the back. Sounds like you have to replace the pads anyway, and that should be done on both sides. In the process of doing that you may discover the cause. The first check is to verify that the calipers on each side are both configured the same way, and are properly lubed & sliding on the rails smoothly like they should. Bent guide pins are pretty common cause, so check for that. Guide seals can swell and bind up the caliper too.

if both pads on problem side are worn to the same extent, I would imagine the problem is with sticking piston, but if one pad is worn much more than anotehr, it would point to the problem with guide pins

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To find out which caliper is stickingm jack up both rear wheels and spin by hand while someone presses and releases the brake pedal. If one side drags after the brake is released, that is the bad caliper, it is sticking closed(or the flexible line to the caliper is.) . That should be on the side with the worn out pads.
If neither side drags, the side with the better looking pads is sticking open and that caliper should be replaced.

If you go to a mechanic , most will want to replace both calipers because they don’t want you coming back with problems but I don’t work on cars for money and I have never had a problem replacing one caliper when the other one is working good.