Rounded off bolt on caliper

I rounded off a bolt that hold on a caliper on my wifes car the other day while changing brakes. I did while tighting it so atleast the new pads are on. I knew that the bolt did not look good and shuld have went to the parts store but i did not. I have actually never have done this on brakes before. Normally I would use a setaline torch to heat it up and use a pair of vice grip to rutn it. I do not know if I can do this on a caliper because of the hydraulic fluid. Ideas? Taking it to a mechanic is not really an option. I have not taken a car to a mechanic for 12 years now.

You say you did this while tightening it? Is it tight? Will you own the car long enough to need to do another brake job?

Use a Stillson wrench, commonly called a pipe wrench on it if you can. By design, a Stillson wrench squeezes the fastener tighter as you push on the wrench. It usually damages the bolt, but you’ve aready done that.

I wouldn’t use a torch. The heat might damage the seals on the caliper piston. They make sockets specifically to remove rounded off bolts. I would go ahead and remove and replace the bolt. If it’s in bad shape, it might fail.

Go to a local Sears store and purchase this set Pound the appropriate sized tool onto the rounded bolt and remove the bolt.


You also might be able to take a slightly undersized regular socket (12pt works best for this) and pound that on to it to remove the old bolt.

Then buy a torque wrench and use it when installing the new bolt. Caliper bolts should not be going tight enough to get anywhere near rounding off when tightening them. Removal might be a different story if they get seized up for some reason.

I had a similar issue on my old Camry. I took the blade out of the hacksaw and there was just enough room between the halves of the caliper for me to cut the bolt, leaving some above the edge to get a vice grip on. With a little WD-40 it came out and I was able to replace it. It took about 15 or 20 minutes to cut through it.

How big is your “bag of tricks” for dealing with damaged fasteners? sounds like you need to make some more room, you would think after 12 years you would have some experience with damaged fastners.My rule is “you damaged it you get it out” When you suffer the consequences for bad mechanical habits a few times you start to employee better practices. The “setaline” torch is a tool of last resort, not the first one to grab.

I admit I was lazy this time. I should have replaced when I noticed it instead of tightening a damaged bolt. Thanks for all the information. I will go to sears to see if they have a lager set of the fastener removers. I tried a smaller 12 pt socket when it first rounded off, that usually works. I never thougth of a pipe wrench might try it first. Thanks again