Is my brake caliper seized?

[Stu]

I've had this peculiar issue with my front-left brake where I've seen a ring of rust due to non-contact. I went to a shop, was told that the pads are essentially new and probably aren't bedded yet.

Well, that was about a month and a half ago. I haven't seen any improvement whatsoever, and the brake seems to be slightly discolored compared to my others. Wheel cleaner that I sprayed onto it about 4 weeks ago still has not come off. Could I have a seized caliper? I stopped using the wheel cleaner once I saw zero improvement.

Front-left:


Front-right (what's up with the gouge in the rotor?):


Rear-right:

[danewilson77]

Bro....take the caliper apart...and inspect that sheeet. Before you remove the caliper from king pin.....lossen the two caliper slide bushings...by removing the dust covers, and loosening with approiate sized hex socket.

Super easy bro. Then....lube em up with some good grease....and then you will have verified freedom of movement.

I'll see if I gots some pics. Do you need more help than that?

[billschusteriv]

You can check the caliper by rotating up and away from the rotor (like doing a brake pad change) and force the piston in with a C-clamp/2x4 or a "caliper press". Note the amount of travel.

Then reinstall the pad, reinstall the caliper on the rotor and pump the brakes. Don't pump the brakes if the caliper and pad are not in place over the rotor - you could overextend and damage the piston and seals.

Then rotate the caliper up and away from the rotor again and repeat the above process with the C-clamp. Did the piston move?

[danewilson77]

Yup...Billy is correct.

The guide pins are spotted in this video...right at the beginning.

[billschusteriv]

Bro....take the caliper apart...and inspect that sheeet. Before you remove the caliper from king pin.....lossen the two caliper slide bushings...by removing the dust covers, and loosening with approiate sized hex socket.

Super easy bro. Then....lube em up with some good grease....and then you will have verified freedom of movement.

I'll see if I gots some pics. Do you need more help than that?

Good stuff Dane.

They also make a rebuilt kit - so you can DIY. Rebuilding the caliper is not difficult.

I don't have access to the proper tools to rebuild to my standards. I like to disassemble, run everything through a bath of parts cleaner, dry with compressed air, put it in a sand/bead/media blasting cabinet to get rid of residual stuff, run through parts cleaner again, and then re-assemble with the new parts.

I had a blockage in my right rear caliper on my e30. Needed to take everything apart as described in my rebuild procedure above and then hook up compressed air to the port where the brake line hooks up. You could have a blockage. Best way to detect this is to bleed your brakes - see if you can get fluid from this caliper.

[danewilson77]

I honestly would take apart and look for freedom of movement.

[static667]

You can check the caliper by rotating up and away from the rotor (like doing a brake pad change) and force the piston in with a C-clamp/2x4 or a "caliper press". Note the amount of travel.

Then reinstall the pad, reinstall the caliper on the rotor and pump the brakes. Don't pump the brakes if the caliper and pad are not in place over the rotor - you could overextend and damage the piston and seals.

Then rotate the caliper up and away from the rotor again and repeat the above process with the C-clamp. Did the piston move?

When you do this, crack the bleed valve open and let the fluid run out. I've been told that forcing fluid back through the abs system could cause some issues.

[billschusteriv]

Good stuff Static. I'll be sure to do this next time.

[static667]

Get yourself about 18"-24" of tubing that fits snugly over the bleed valve's head and an empty water bottle. Drill the right size hole in the bottle lid and insert the tube. You now have a mess free bleed bottle. These things rock.