2003 Chevrolet Trailblazer Power steering gear mounting bolts.

Usually to remove a bolt, you use a wrench or socket. I wouldn't know the actual size? To work on your own vehicle, you need a basic set of tools. Wrenches and sockets. Standard and metric sizes. If I grab a socket that is a little too small, I grab the next size up, go from there. If I grab standard size sockets and the size seems to be in between, then I look for a metric size socket. I don't know how most people do it, that's how I do it.

I'm not trying to be flippant or a SA. That's just how I do it. I will look around for the proper wrench or socket, but, our database won't give size.

I did find some socket size info, but, for 06 trailblazer, 13/16 deep and regular socket or wrench, whichever works best. I can't guarantee the 03 and 06 will use the same size for rack/pinion mounting bolts.