Howdy. I have removed the backhoe operator control valve and kitted the boom up/down valve. Now that I have it all back together hardly anything works. The boom cylinder will move in and out about a inch. It swings right ok but will only return about 20% from where it starts. Crowd/curl nothing. Loader and outriggers work fine. I'm assuming this is air? Other than letting it run how do I get the air out? I can find 1 big canister filter for the hydraulics under the cab but are there more tucked in somewhere? I have the shop repair manual and the tech manual but neither shows anything about filter or screen location. Thank's.
Oh, also, the pump is really noisy but when you engage any valve it gets quiet and the rpm’s come up 2-300.
That's a closed center system, so the pump destrokes and SHOULDN'T be pumping any oil when no valve is open. If you're having that much noise and RPM jump, there's an oil leak somewhere and the pump is pumping a significant volume at full pressure, then reducing the load when you reduce the pressure. That's my guess. Is all this at idle? or full RPM? I'd start it at idle, and keep two or three backhoe functions operating at the same time back and forth part of the stroke, closer to the end each stroke, until they have all gone full stroke, but never deadheaded all the controls at once. If you keep another function operating, that will prevent the pressure from reaching max until you have all the air worked out. Then see how the pump sounds and what the rpm does when the oil is warm, full and the air is bled. Maybe the screen is listed as a transmission screen if the transmission and hydraulics share the same oil? can't believe there's nothing in the manual about the screen...
Mostly at idle. I ran it to 1200 rpm for a bit but everything stayed the same just faster. The pump was quiet until I pulled the valve and the loader and outriggers work fine so it must be related to the backhoe valve. I just wasn’t expecting to take so long to get the air out. I’ll go out and try some more after while. Sure would be nice to see some new movement at least on something!