Not in the shop with the service manual right now so I'm doing this from memory. The accumulator like you mentioned was something to check and they wanted it between 90 and 110 psi. Can you check this with just a regular air pressure guage? guess I haven't looked at it yet, but they were saying you were supposed to use some special tool.

They don't specify a flow rate to be tested for it. They do specify a pressure though. Seems like it was something like 235 PSI or thereabouts (I'll look again before I test it). Am I missing something in the manual?

For what it's worth, I spent some time with a tech in their room where they keep their service manuals while he was trying to learn what way I should install my bushings in the shaker system. The later combine service manuals are significnatly more comprehensive than the older ones. It seemed the 2188 was when things started getting really good as far as the service manual is concerned. The 1480 has some good things (like hydraulic diagrams, electrical diagrams, etc) but is a little lacking in other areas like the shaker system, etc.