car vibrates at 70mph feels like rear brakes slightly locked?

[grimm]

i've noticed some new vibrations when driving lately, it's not totally constant and seems to change amplitude. It feels like it's coming from the rear driver side wheel. when i got to work, which is about an hour drive i felt my rotors and that rotor was a good bit hotter than the others. I am struggling with what the cause is. anyone ever experience anything similar. My car is a 2002 wrx.

[grimm]

well i just took my rear caliper off and tried to compress the piston and got the big FU from it. It wouldn't budge at all. So i removed the shims so the pads weren't pressed against the rotor. I figure if i can't compress it, it shouldn't be able to extend either so I shuold be able to get home without it riding on the rotor for over 50+ miles at 60-70mph.

FYI 150K **** just start to fall apart.

[SovXietday]

I was about to say it's your piston in your caliper freezing up. I literally just fixed one in my DD yesterday.

You either need to pull the piston out, clean it off, regrease it (I use vaseline for this actually lol) and then put it back in. Or just get a whole new caliper. Your choice.

It's really not anything to worry about. Nothing is "falling" apart or anything. The boot on the caliper probably went and the piston got rusty inside. Happens, it's a high stress part.

[abrok99]

yeh what he said. also check your pads to see if they are more worn than the other side. i would recommend replacing the pads/rotors after fixing or replacing the caliper just for good measure.

[Protege v2.5]

just curious but are they the type of caliper that the piston has to be spun to be compressed?

[jpalamar]

I was about to say it's your piston in your caliper freezing up. I literally just fixed one in my DD yesterday.

You either need to pull the piston out, clean it off, regrease it (I use vaseline for this actually lol) and then put it back in. Or just get a whole new caliper. Your choice.

It's really not anything to worry about. Nothing is "falling" apart or anything. The boot on the caliper probably went and the piston got rusty inside. Happens, it's a high stress part.

I highly doubt Vaseline is designed to take the amount of heat generated from brakes.

[grimm]

i plan to rebuild the caliper this weekend if the kit comes in time. Last night i got the piston to compress back into the caliper, i drove the car around the block, then took it off and compressed it again. I did that one more time making sure it would be ok for my ride to work today. Today it didn't seem to rub on my way in, but i brought the tools i would need to compress it if it does seem to freeze again.
i understand it's normal wear and tear. just blows.