Quick question. New to owning an excavator. Early 90's Hitachi EX60URG. Essentially an EX60-1 but with a compact counterweight (doesn't stick out much at all) and one of those funky booms that can be offset for digging next to a wall. When replacing the main filter and pilot filters, is it necessary to bleed the air out of the hydraulic pump(s)? I have an EX60 service manual - very similar machine. It doesn't say to bleed any air out of the system when changing the filters - just when draining/refilling the hydraulic tank. I'll of course prefill the pilot filter housing prior to screwing it back on there to minimize the amount of air in there. The main filter didn't look like bleeding was necessary at all as it was just sitting in a sump of oil... The pictures in the manual are pretty crappy and the manual can be vague at times. I am of course worried about damaging the pump(s) with a slug of air. Second question. After operating a while (warm machine), the boom lift is very slow under load. I'll still pick up a stump - just painfully slowly. Down seems fine, unloaded seems fine. Arm in/out seems fine. Swing seems fine. Same with curl. I just changed the main filter and will exchange the pilot filter prior to operating the machine (hence my previous question). Hopefully that'll clear things up. If not, any other suggestions? thanks, Chris
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