Caliper problem? Something else?

[CraKaJaX]

Just the other day I noticed my passenger side rear rotor wearing unevenly. The pad is only wearing about half of what it should be (the inner radius is wearing while the outer radius is not at all). Turns out that it looks like both rear rotors have the same problem. There's no squeal (yet) and no shaking of the wheel (yet), but I want to fix this ASAP.

My first thought was the calipers. However I am unsure of when to replace the entire caliper vs. replacing just the pins. It seems to me like the pads aren't making full contact with the rotor because of a seized pin - but both driver AND passenger side at the same time? Seems highly unlikely... but that's why I'm here. Of course I'll be replacing the rotors and pads new, I just am unsure of what to do/buy with the calipers. Any thoughts of what else it could be?

FWIW - 2008 Subaru Legacy 2.5i

Just so you have a better idea, here's a similar picture of what I'm talking about.

http://i111.photobucket.com/albums/n142/nicholasrusso/IMG-20140605-01667_zpsea34f7b4.jpg

Thanks guys

 

[lsd]

Bleed the system first you might have air in the lines. How does the pedal feel when you press it? You can lube the pins while you're there bleeding them.
If it's not that it could be seized caliper pistons. If it's a daily driver I'd just replace the entire assembly if it's that. Water in the system will cause the caliper to freeze or not move freely.

 

[CraKaJaX]

Pedal still feels normal. They haven't gotten to the point I have to slam them to the floor just to stop. I believe I caught it fairly early... so there's still life.

I do plan on bleeding them and at LEAST lubing the pins (if not replacing) when I'm down changing the rotors and pads. I suppose I could bleed the brakes, replace the rotors and pads, lube the pins and keep an eye on how the pads/rotors are wearing? I didn't want to drop the cash on an entire assembly for both sides unless I knew for sure that they were the culprit. Is there a way I could tell for sure when I'm down there replacing everything else?

 

[jlee]

When you take it apart, lube the slide pins and slide the assembly on it - see if there's any binding at all. If everything is straight and smooth, you might be fine.

 

[Bartman39]

When you take it apart, lube the slide pins and slide the assembly on it - see if there's any binding at all. If everything is straight and smooth, you might be fine.

jlee is correct on this it sounds like...? The key to make sure the caliper pins are not corroded and binding in the calipers... A buffing wheel will do in this situation and some HD grease will keep the pins from freezing and causing what is happening to your brakes...

 

[CraKaJaX]

When you take it apart, lube the slide pins and slide the assembly on it - see if there's any binding at all. If everything is straight and smooth, you might be fine.

If it's not straight and smooth, how do you know if it's the pin or the assembly itself? I already plan on lubing the ones that are there, but I want to replace whatever I have to while I'm down there when everything else is being replaced.

 

[boomerang]

When you take it apart, lube the slide pins and slide the assembly on it - see if there's any binding at all. If everything is straight and smooth, you might be fine.

This. I would remove the pads and clean the shim surfaces also. Make sure the pads aren't binding in the calipers. I would do all this before replacing anything. I usually take the pads and rub them on some coarse sandpaper a bit too to remove any glaze before reassembling. Unless there is so little pad material left that they need replacing of course. Do all that and drive it a while and see what your result are.

 

[jlee]

If it's not straight and smooth, how do you know if it's the pin or the assembly itself? I already plan on lubing the ones that are there, but I want to replace whatever I have to while I'm down there when everything else is being replaced.

You can inspect the pin and see if it's rough, bent/etc (shouldn't be). If the pin is nice and clean and straight and lubricated and you're still having problems, then replace the caliper. I suspect that won't be the case. Also make sure the piston assembly is in good shape - if you have torn boots or the piston is seizing in the caliper, you'll want to replace or rebuild it.

 

[JCH13]

+1 on seized slides.

Make sure you use caliper slide grease (not just any old grease) and make sure any boots or seals are in good working condition.

 

[CraKaJaX]

Thanks guys. Initially I was suspecting seized pins as well, but I've never seen it where -both- sides seized up at the same time! As far as removing the pads and cleaning them ... I think the pads and rotors are beyond the point of repair. The rotors are shot unless I have them resurfaced. Since this is my only vehicle and I currently live on my own, resurfacing isn't really an option. Luckily they're cheap enough to replace.

Time to look for some Advanced Auto coupons that are floating around

 

[JCH13]

For what it's worth: the last brake job I worked on had both rear slide pins so corroded we couldn't get them out and had to buy new calipers. One of the brake pistons came out in chunks, it had hyper-extended and become jammed in the rotor vents (the rotor surface was gone).

 

[BudAshes]

Thanks guys. Initially I was suspecting seized pins as well, but I've never seen it where -both- sides seized up at the same time! As far as removing the pads and cleaning them ... I think the pads and rotors are beyond the point of repair. The rotors are shot unless I have them resurfaced. Since this is my only vehicle and I currently live on my own, resurfacing isn't really an option. Luckily they're cheap enough to replace.

Time to look for some Advanced Auto coupons that are floating around

Honestly calipers, pads and rotors are so cheap and easy to install it's probably just worth doing it. I'd probably get the calipers locally though as the core charge is usually more than the calipers themselves and I can't imagine shipping them is cheap.