Size of hex head bolt on a 2001 Chevy caviler 2.2 front brakes

Allen wrenches usually come in a set, try 3/8.

these are what is called a Torx fastener and are I think a number T55 or T60.

caliper or most brake part bolts are between 10mm and 19mm for the wheel bolts , get a set online if haven't got tools , don't waste time and money just trying to get a particular size as many different manufacturers are used for the same part and may just get one that uses a different bolt head size

Then it has to be a Metric Allen Size

Need to get a complete set of Domestic,
Metric & Torx Drivers,then you have all you
need for any brake work, as well as other repairs,
for any vehicle

Snap-On Tools--- while expensive, is the way to go

Hello rcvez
Without a model and year I can only give you a general description on how to change chevy calipers.
Jack up the left front and put a stand under it, then remove the wheel. Turn the wheel all the way to the right
On the back of the caliper you'll see 2 female hex bolts(allen head) the size should be 5/16 or 3/8, use a
male hex socket or an allen wrench to remove the bolts, if you use an allen wrench you may have to give
it a couple of wacks with a hammer to loosen them up. Now use a pry bar work the top and bottom of the
caliper and walk it off the roter, set the caliper aside so not to strech the hose. Next, put the new pads in
the new caliper and bolt it up to the bracket, remove the hose from the old caliper and bolt it to the new
caliper, be sure the bolt is clean and use the new copper washer that came with the caliper. Now repeat
this on the right side, bleed the brakes and thats it. Hope this is helpful.

someitmes, you have to remove the brake caliper to get the rotor off. It has 2 bolts going from the inside to the outside. Usually a hex head or a Torx head bolt. Same as Ford Escape.

need a torx 55. must remove caliper in the bracket then remove the caliper. Bracket bolts are 17mm I think.

IT IS 7MM HEX BIT..AVAILABLE AT MOST HARDWARE/AUTOMOTIVE PARTS STORES..BE CAREFUL WHEN REINSTALLING..VERY EASY TO STRIP THREADS OF STEERING KNUCKLE

I think they are a t30 Not sure exactly, But ask the auto parts guy at the store he will be able to tell you exactly

if you have a torch handy, add some heat too the sorrounding area of the bolts should come apart easy then