Install the air compressor mounting brace and four capscrews on the cylinder block beneath the air compressor.
Start installing all four capscrews.
Loosely assemble the brace capscrws to the air compressor rear flange.
Align the brace thru holes with the holes in the cylinder block. Make sure the mating face of the brace is as close as allowed by stack-up to the rear flange of the air compressor.
Insert and hand-tighten the capscrews into the cylinder block.
Tighten the capscrews into the air compressor rear flange.