Found this out trial and error. First do the MC. Get the air out of it using the proper procedure (can't rememeber it), get it ready to install.

Set up the installation procedure to have minimum time that the brake lines are open. This means first loosening the line fittings until they drip a little and then barely tightening up. Then remove the bolts holding the MC to the power booster. The MC will stay in place OK.

Remove the fittings, hand MC to helper, get new MC from helper, connect fittings ASAP. Wipe up leaks, fluid eats paint. Then reattach bolts and tighten fittings.

OK, there's a little air in the lines. If you were quick enough, the bubbles are still in the vertical lines down to the junction block. They will float upward, slowly.

Next do a pad replacement job on the front brakes. The action of pushing the old pads back, and thus the pistons into the caliper cylinders, will force fluid back up into the MC, taking the air bubbles with it. I have had good results with this every time. BTW, wrap a rag around the MC filler cap in case fluid is forced to overflow. AND, remember to gently pump up the brakes as soon as the job is done. If you forget, it will be the only time you ever forget that little task.

Good Luck,

Bob

:>)