Wagner 505 paint sprayer
I know this question is a stretch from the normal theme of this forum, but I have been all over the net and this is a last resort. Has anybody replaced the diaphragm in a 505 Wagner paint sprayer? I bought a used one at an auction and the guy said he thought it needed a new diaphragm. It was pretty obvious where it was located, so I took off the pump head and of course all the fluid between it and the piston ran out. I ordered an new diaphragm (the old one looked ok) and a quart of wagner hydraulic fluid. I didn't have a manual, so I looked on line for one before reassembling it and the first thing I found was a picture of the head with the warning NEVER REMOVE THESE 4 BOLTS (which I had already done) Is there anything I should know before filling the diaphragm cavity with fluid and replacing the head? Everything I can find advises to return it to a Wagner service place to have diaphragm serviced. I can't see any obvious reason for this unless there is some special procedure to insure that there is no air entrapped in the fluid. Anybody been there and done that???
might be worth talking to a hire company tech... they usually know this stuff