I am changing my front rotors and thought I was home free after getting the disc retaining screws out using an impact wrench + heavy hammer, but now I can't get the 17mm caliper bracket mounting bolts loose. Any advice on how to loosen them?
(I had started with the screws because I thought that that would be the rate limiting step for do-it-yourself.)

 

Heat the bolts, or you can get some PB penetrating lubricant.

 

The normal mounting torque for those bolts is only like 24 ft-lbs. They should come loose relatively easily. Make sure your using an open end wrench to hold the caliper pin when you turn the mounting bolt. You have to be careful not to damage the pin boot with the wrench. The last mechanic to do this may have used some locktite on the caliper mounting bolts ( I do, but the factory doesn't), or they may be locked in because of heat cycling. So, you may have to give them a sharp bump, rather then a gradual exertion of torque to get them to break away.

Good luck.

 

I think he is talking about the two bolts that mount the caliper assembly to the wheel, not the pad retainer bolts.

I can't imagine a proper size 6 pt. 1/2" socket with a breaker bar wouldn't loosen it in a jiffy... I can usually break them loose with just an oversize box-end wrench.

 

Thanks Gloffer, but these are not the caliper bolts for changing pads. They are the large 17mm bolts that hold the whole caliper assembly to the knuckle. The caliper assembly has to be removed to get the rotor off (which I have already gotten loose by removing the screws). That's where I am stuck. Anyone who removed the calipers for rotor change or powder coating with advice?

 

I tried a long box-end wrench, even with blows from a hammer and penetrating oil, with no success. Must be seized from all the overheating from track events. Other than the breaker bar, which I don't have, any other suggestions?

 

Put a piece of pipe over the box end wrench or standard 1/2" ratchet to increase leverage.

...or better yet, if you don't have the right tools, run down to sears and get a decent Craftsman 1/2" metric socket set. They are pretty inexpensive, making working on your car much more enjoyable, and in the long run will be much cheaper than screwing something up because you don't have the right tool for the job.

 

Oops, sorry, mine came off without any trouble either when I replaced my rotors last month. Try some liquid wrench or this stuff called PB Blaster. If you can get one back in there you might try your impact wrench with the proper size socket on it. The torque spec on those bolts is like 80ft-lbs.

 

I'll try the pipe over the long box-end wrench (Craftman btw), though there is not much room under the fender to allow much more leverage than the wrench itself. And I will also invest in a Craftsman 1/2" socket set in any case.

 

Use a 1/2" tire arm about 18" long. It should just come right off. A good selection of the right tools make the job easier.