Uneaven brake pad wear - rotor warped or something more sinister?

My rear brake pads started to get squeaky, so I pulled them out to replace them and was surprised to see that the drivers side pads were dramatically worn compared to the passenger side (they are on the right hand side of the pic):



This is the first time I've changed the pads since I bought the car last year, so I cannot swear if both pads had been done at the same time, but they were both the same model/brand etc. so I would have to think that it was done, so maybe something is up?

I've changed the pads on both sides, bled the brakes and all seems to be working fine, and the car pulls up evenly and straight when braking (as it did before I swapped the pads). Both rear rotors are not even close to the minimum thickness and there are no really bad marks/gouges on the actual rotor face as well.

What makes me think the rotor on that side is warped is that it rubs on one place when I rotate it, but it's only briefly and not very loud. My eye cannot see any wobble but I can hear the sound as it rotor passes the one spot.

I'm happy to replace the rotors and can do that myself, however I just wanted to check if it may be something else apart from the rotor to cause such uneven wear between the two sides?

I've had the new pads on for about 2 weeks now and I removed them on the weekend to check and so far both are wearing even on both sides.

This is on a VRX Wagon if it makes any difference?

Cheers!

If the pedal doesn't pulse when braking then just keep using the rotors. The pad wear could be due to the callipers slides not moving freely, if so just remove the slides clean them lubricate them and refit.

As above check the sliding pins and whether the floating part of the caliper is moving freely on them. Given you've already done the hard yards of jacking the car up, removing wheel, etc I would remove them, clean them and re-grease them.

Also look at the condition of the piston and its rubber seal. If there is any sign of corrosion or the seal failing, then you will need to get the caliper rebuilt.

Did you notice excessive air coming out of the side that wasn't worn when you bled the lines?

Also one of those worn pads looks to have marks on the steel backing plate. Check both sides of the rim to make sure they aren't heavily gouged.

EDIT: Should add that if the pad was dragging it could have been generating a lot of heat, so I think it would be worth comparing how freely the hubs rotates on each side.

Was just one side only have new pads replaced by the previous owner. Maybe to pass roadworthy. Check to see if pads on either side are by same manufacturer!!?
Check for any differences even tiny. Rather miserable if this proves correct. Notice pad on left divided in the middle. If the division goes right down to the backing plate, then looks like there's your answer, as plate on right shows no division.

I think you will find that the line"division" on the pads doesn't go right thru the pad, i think it is worn right down, thats why its not visible, son in law who is A grade mechanic said possibly sticky slide, piston etc same as frosty/ryan said above, doubt if it would be proportioning valve/abs unit if fitted, but said could be anything only way is to check whole system, is best to machine disc's when replacing pads/bleeding brakes if they have not been machined before since new?

I had a similar problem. The slides had seized so only one side of calliper moved and made contact with the rotor, while the other side did nothing.

Thanks for the replies guys, sorry for the late reply I've been swamped.

The pedal does not pulse at all, and the car pulls true to a stop. I'm pretty much getting the squeaking noise at slow braking speeds but not all the time. I'll jack the car up tomorrow hopefully if it's not raining and I get the time and give the slides a good clean and lube. I've been meaning to get to it for a while but my daughters car needed all of her rotors changed out.. when it rains, it pours..

I did bleed the brakes when I did the new pads and the fluid was fairly fresh and no noticeable air that I could see from the opposite side, at least that I can remember now . I've got front pads to do as well (I bought them at the same time) so I'll do a complete bleed and flush when I fit those. I have an air compressor brake bleeder thank god, chich makes the whole thing a hell of a lot easier.

The hubs, off memory, felt even when rotated, but I'll check that again tomorrow. It will give me a chance to see how the pads are wearing on both sides as well.

I'll also check to see if the rotors are gouged or not as well.

Joel32, what was the outcome for you, did a clean and lube fix the problem?

Cheers!

With the wheel off you should be see the calliper move either side when someone else hits the brake pedal.

The slides I managed to get out were rusty. You could sand them back and lube them or buy replacement slides. One of the sides I couldn't out so I had all the callipers rebuilt at a brake shop.

Right, reviving my own thread!

In the end it was the actual caliper that was seizing occasionally. I discovered this while on a road trip down to Canberra from Brissie, luckily it happened just outside of Canberra and I limped to my parents place. Upon inspecting the brakes when inspecting the caliper I discovered that it would push out but not go back in unless forced.

Luckily my father has a nice shed and tools, so I removed it and had it rebuilt in Canberra, I put new pads in and made it back home to Brissie fine.

To be safe I've ordered replacement rotors for all 4 corners of the car, with new brake pads, slider bolts etc. I also scored two new OEM front calipers off ebay which I'll put on the front, I'll do a write up with pics when I do.