Help! Rear brakes sticking, what's this piece on the rear caliper?

[BATOYGIO]

My rear brakes have always created a ton of brake dust, and at about 30k miles I checked the rear pads to find they were almost completely worn. I changed the pads, greased everything up back there and the brake dust still continues to pile on. Before I go changing calipers I wanted to know what this little piece does, does it adjust brake strength or the amount the caliper backs off when I let go of the brakes?? I was thinking I could turn it and maybe make the back brakes less aggressive but I don't want to touch it without knowing what it does for sure.image.jpg

[firefighter]

Pic doesn't work.

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[birdmang8]

That is a bleeder valve. It is used to get all the air out of the lines.

[birdmang8]

Is the problem occurring on both sides?

[Napalm]

bleeder screw - open it to get air out of the system - or to push old fluid out.

question - do you trip the stability assistance often? say on right hand turns? Part of the reactions of the stability system is to feather the brakes to keep the car in alignment of the intended steering wheel input.

Otherwise - you might have a sticking caliper but if you cleaned and greased the pins - that is less likely. did you grease the tabs of the pads and the metal spring clips. Make sure you use a brake grease not a normal grease. (due the heat)

[birdmang8]

Doesn't hurt to make sure the tabs are free of debris and corrosion, this in combination with the brake grease will ensure the pad doesn't have excess pressure on the rotor when brakes are not applied.

[BATOYGIO]

Thanks for the quick input everyone, ok so I won't touch that valve, good thing I asked first. Yes it happens to both sides equally. I greased the pins, but I'll try to grease those metal tabs the pads slide into as well.

Interesting point with the stability system using the rear brakes to keep the car in check. It definitely comes on every now and then, but I would imagine far from often enough to cause the excessive wear and dust. I probably see it kick in two or three times a week tops.

Hopefully greasing the metal tabs works, I'll give it a shot this weekend, wash the wheels, and then drive for another week to see if it builds up just as much.

[MIEngineer]

Here is the information we need:

Do the calipers slide freely/easily on the pins?

What brake pad did you install?

Brake pad compound is the culprit of dust. 30k is a good life span for a G8 with what I am going to assume is a non-factory brake pad that was installed.

If you go to a "ceramic" [which is just a commercial term] vs a "semi-metallic" compound you will see less dust - but if the car is not a daily and is exposed to varying weather, the compounds ability to remove oxidation from the rotor is substantially less as it is a less abrasive compound in general terms

[Napalm]

indeed when you get your calipers apart again - like he said even thought you greased them up you should be able to grab it and move it freely - and evenly along the pins.

OH make sure when you take the pins out and put them back to get that rubber dust boot settled in the groove on the pin such that is accordions smoothly as the pin goes back and forth. Some people accidentally get those bound up on the pin and it won't move right.

regardless of the use pads should last more than 30K miles. I DD my car and I would say you trip the stability light more than 4 times more than I do monthly. so perhaps you are making it pulse the rear brakes more often than you think.

What tires are you using?

[BATOYGIO]

The brake pads are the red ebc ones, but the ones that wore out at 30k miles were the stock ones, the car is far from a daily driver, got it new in 09 and I currently have 31.5k miles. I drive it once a week so the 2-3 times (sometimes less)the tcs light comes on is in that one day a week. The front pads are still fine with tons of material. I'll check that the assembly slides easily this weekend when I grease the metal tabs for the pads. Let's see in a week or so once I grease everything and wash the wheels.