Bolt size for 96 chevy front caliper

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

1st jack up your car & remove the tire. The calipers are generally held on by 2 large allen head bolts. Personally I prefer to use an allen wrench that fits on a ratchet, but just an all steel allen wrench will work. You should be able to remove the calipers at this point. When re-installing the calipers you'll need to push in the caliper pistons (usually 2 per side of car) I've had good luck using about a 6" c-clamp to push the caliper pistons back in . I hope this helps.

Allen wrench size to remove brake caliper on my 2008 mercury mariner

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.

The caliper guide pins will usually have either a 3/8 inch or a 5/16 inch allen head bolt. If the brake calipers are found to have phenolic pistons then it would be advisable to change them with calipers that have metal pistons.

I think you need a 3/8" allen wrench.

There are no springs on the front brakes of a GM vehicle. The calipers are floating type, and all alignment is accomplished by sliding bolts in the caliper. If it's these bolts that you are referring to, then it takes an allen wrench.

some are 7/16 and some are 3/8 amd some are torx

For a wrench or for the acctual bolt size.
To remove front pads..you need 8mm allen socket to pull the caliper guide pins, then 17 or 18mm..To remove rear pads...you need 13mm socket for lock bolt on guide pins and 15mm open end wrench (thin section to hold guide pin while you remove lock bolts..I ground down a spare wrench). You DO NOT have to remove rear carriers to change rotors..just remove lock screw and angle rotor out. The B5 Passats don't have the electronic parking brake so you don't need VAG Com to change pads.
Installation tips:
Clean and regrease the guide pins with "synthetic caliper grease"
Rear lock bolts come with preapplied thread locker and "are not to be reused"..I just wire brush the threads and use some Loctite Blue on em. I smear just a little antisieze on the inside bore of the rotors and on the lock screw threads to prevent corrosion and make next rotor change ez. Torques:
Front caliper guide pins:18 ft lb
Front carrier bolts: 89 ft lb
Rear guide pin lock bolts:26 ft lb
Wheel lugs: 89 ft lb

It's either 8mm Allen OR 8mm 12 point