I got the caliper off, but one of the carrier/hanger bolts is rounded (from a previous owner, I believe) and stuck. It's the lower bolt, and it's difficult to get at. I tried PB Blaster and a pipe wrench. Still holding fast. Any thoughts on freeing a frozen, rounded bolt in a difficult place? Also, if I ever manage to get the bolt off, it will need replacing. Is it a standard size I can find at a hardware store, or is it a Volvo part (or OEM part) that I need to buy specifically for this? Thank you, as always!

Hi Kevin,

Agree that the application of heat or other methods are warranted given the situation but if access to the stripped bolt head is the major obstacle to applying the torque required to turn it, you might look into a "bolt-out".

One of these (https://shop.advanceautoparts.com/p/irwin-bolt-out-with-case-394001/9010233-P?) saved my butt recently when an engine mount bolt head stripped during removal. It even worked to put the old bolt back in!

Best of luck,

Will

Cut or grind the bolt head off and slide the caliper off. Now you have the bolt shank to heat and grab. Use the good bolt to match the new one. This is the easiest way I can think of, unless you want to struggle for hours.

I used to get OEM rotors which come with 2 bolts, with a smear of red loctite on them. Take the top bolt to your hardware store, not Home Depot or Lows, and get a hardened steel match.

To remove the lower bolt, you will need a torch to get the bolt red hot, and then use the pipe wrench to get it off.
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Keeping it running is better than buying new

I will second the suggestion to get good quality hardware. Stay away from Lowe's. I've had several of their "grade 8" bolts shed threads or break at half the torque rating required for an application.

I go to FastenAll suppliers for critical hardware.

Erwin

You can find the brake hardware at most quality parts outlets
Get the new pins and other brake hardware there.
Put Never-Seez in the threads, so next time isn't a disaster.

I found a set of long handle Torx keys on Ebay (they look like Allen keys)
They're perfect for the brake pins.

The ones I got were security Torx with a little hole in the tip.

If you are trying to remove the bracket for the caliper, get MAPP gas on the bolt head for a minute or so, and the heat should free that bolt, with the pipe wrench.
Get it red if you can, a little PB spray or Mystery oil won't hurt when it's hot,
just don't breath the fumes. If it doesn't bust loose at first heat it again a little longer. Get that bolt at a quality hardware, avoid Home Depot hardware which features crap bolts out of cheap soft steel. UGH ask me how I know.

Bill

Torx?
The pins in my V70's (up to now?) take a 7mm hex.

Did Volvo use Torx on the XC's?