Stubborn/stuck caliper bolts. Advice needed!

Just like the title says I have stubborn/stuck caliper bolts. Any advice on getting these loose would be much appreciated. Working on a 2001 Silverado 1500 2wd I tried driver front and rear and could not get any bolt to budge. Caliper bolts and caliper bracket bolts would not budge. Sprayed wd40 and {deleted canoe 2 days later!} let that sit 5 minutes or so nothing, hit the heads of the bolt with a soft mallet and re sprayed the wd40. Still nothing.

What else can be done? Or is there any better method. Thank you for your time!

When I have a stubborn bolt that is hard to access, I use the combination of wrench/ratchet and hammer. 

I put the socket on then bolt and then use a hammer to hit the ratchet handle to get the bolt to turn. Short breaker bars work well, like the short 3/8” from craftsman.

The trick is to get a good solid bite on the bolt before getting the hammer out, and then use a hammer with enough weight to get some force on the tool.

I like a 4 lb engineers hammer for this, it’s got enough weight to move things but is easy to handle. 

WD40 is not a penetrating oil. Get something dedicated to the task: PB Blaster, Liquid Wrench, etc. It may need a lot more time than five minutes to work.

Agreed on percussive force. Make sure the socket fits the bolt head well or you'll round it. Only hit your ratchet if you don't mind breaking it - breaker bars or wrenches will be more robust.

I suggest smacking it with a dead-blow canoe paddle

sleepyhead the buffalo said:

I suggest smacking it with a dead-blow canoe paddle

Does that disable the time delay fuse?

Freeze Off is what you need!  Your local auto parts store will carry it.

If you aren't starting to deform the bolt (i.e. round or strip the head) then you still have the option to push harder. It's when you're twisting hard enough to start deforming the bolt and it STILL hasn't moved that you have to get creative. Although, even when something starts to deform from a constant force and doesn't spin, it will sometimes break loose and spin from the rapid percussive force of an impact.  

Caliper bracket bolts on trucks are generally the same size or bigger than lug nuts/studs and have torque ratings around 100 lb ft. You really have to crank on them with a hand ratchet and even if you can get it loose it can be questionable whether you'd be able to tighten it as tight as it needs to be without having a long-handled ratchet or breaker bar. If you had a 6" ratchet handle and weighed 200lbs you'd literally have to stand on it to get to 100lbft.  So look up the torque specs for those bolts and make sure the tool you're using is appropriate to get to those torque levels. Preferably you'd have a torque wrench to tighten it with but you need an appropriately long-handled tool to get it loose in the first place without crazy effort.

Just be mindful of the difference between a caliper bolt and a caliper BRACKET bolt. The caliper bolts hold the caliper to the bracket and are usually something like 20-30 lb ft. The caliper BRACKET bolts hold the caliper bracket to the steering knuckle and are usually much larger and torque to something closer to 100, sometimes as much as 140lb ft. If you try to put that big torque on the caliper bolts they'll snap, and if you try to put the small torque on the big bolts they'll work loose. 

Penetrating oil, 6-point socket, and a breaker bar.

Doesn't the factory put a red loctite on those bolts as well?  I know on my Corvettes the first time I pull off the calipers it is a lot easier if I hit it with a torch for a little bit then the breaker bar.

Vigo said:

Caliper bracket bolts on trucks are generally the same size or bigger than lug nuts/studs and have torque ratings around 100 lb ft.

unrelated to OP's issue, but i almost herniated my ballsack torquing the C4 front caliper mounts to their specified ONE HUNDRED SIXTY LB FT.  i've been in the OE brake industry for 27 years now and that's the highest caliper mount torque spec i've ever seen.