Long gear wrenches, 13 and 10mm iirc. When you go back together with it, stick all bolts in the compressor while it's still off the truck, and put a rubber band around all the bolts so they don't fall out, then install it, tighten the rear 2 bolts first. I always install and remove them from the top of the motor, but everyone tells me I do it ass backwards. I find it easier that way. I've tried doing it under the trucks, and didn't like it.