special tool needed for front brake pad removal?

What type of tool is needed to loosen the assembly that holds the front brake pads on an 87 el Camino. It appear to be something like an allen key, but what I think is the right size - doesn't fit. Is it a special tool? What is it called...and do I get it at a local parts store?

I've changed brakes before, but never on my el Camino. Seems like it should have been a simple thing...

I would appreciate any help and experience this forum has. Thank you for your time.

A 3/8 allen key should do it. It might be metric on an '87. I use the ones that go onto a 3/8 drive ratchet. Your local parts house should have them.

Bob