I have a 1989 IROC. I need to depress the rear brake caliper piston to change the rear pads but my Haynes manual says not to use a C-clamp to depress the psiton. It says that instead I need to use special tool #J-23072 or equivalent. Is this correct in your experience? I tried a search but cannot find a picture of this tool, and could not really follow the answers in the forum re this. Does anyone have a picture they can post of this tool so that I can either make something up or adapt something that might work? Also, if anyone has any tips to make the job easier, I would appreciate it.

correct, the rear calipers have a mechanical type parking brake. the parking brake replies on a screw-like mechanism and thus you cannot simply compress the piston back into the bore with a c clamp. instead you actually need to screw the piston down. this can be accomplished with either a set of needle nose pliers and some patience. Alternatively a tool exists that accepts a 3/8 drive ratchet and has appropriately spaced prongs that mate with indentations in the piston face. i picked out of said tools up at my local princess auto (unsure what the American equivalent is) for $5.

The tools looks like a 3-d wire frame cube.



-Zander

Thanks for the quick reply and picture. I haven't seen that tool before. Generally there is nothing here that matches up with what is available at US/Canadian auto parts stores - mores the pity. I will try the local GM dealer and see if they have something that will work. Otherwise it maybe a case of 'needle nose pliers and some patience'.

you can compress the piston, sure. i did..but i also ruined my calipers. YES you need the tool. its everywhere. autozone, kragen, gm dealership dont sell tools. but if youre lucky you can find it at harbor freights, pepboys, any autoparts store. if you dont live around them, you can order off the sites. I need to rebuild my calipers now. bye

If you have an 89+ with rear discs, you should have PBR's (single-piston alum) and not the old-style iron Delco-Moraine calipers (82-88). I use a C-clamp all the time.

JamesC

Thanks everyone. Armed with the photo The Zander posted, I was able to find the tool very easily, sold here as a Universal Brake Tool. I will check which calipers I have (car was built March 1989) and will determine if I need the tool or the trusty C-clamp. Either way I am covered. Thanks again.

ok, so my actuator screw may be stripped. where do i find a new one. i tried searching, and looked everywhere. i just got my 18019028 gm# caliper rebuild kit, no actuator screw though plze help.! again i need the actuator screw.