We are still working on the boom cylinders but need to fire the machine for a short time. Curious if the boom level is not operated, if we will need to install block offs on the oil lines or not? Looking at the hydro valves, it does not look like it will need it but I was wondering about the load check acting funny or something along those lines.
You'll have leakeage if you don't cap the lines since it has make-up valves that'll open to the cylinder ports whenever there's a higher pressure in the return channel in the valve block.
It is CORREECT Per Eriksson
In this case you need to plug all the lines to avoid leakage, but as a general principle I would plug all lines irrespective of whether or not the System Operation indicates oil should or should not come out of them when I fire the engine up. It's both a good safety & also a contamination control practice in my opinion.
Thanks. I also wanted to ask about purging new cylinder builds. Can we cycle the cylinders safely to purge air or do we need to use the bleeders aways from the cylinders to try and get the air out?
When I do cylinders like that, I use proper pressure caps/plugs on pipe connections, fit one cylinder (if doing boom cylinders), pin it off to base of machine, keep cylinder horizontal, and support rod end of cyl with crane. Have cylinder fully retracted, connect hose to piston side of cylinder. Start machine and the make up valve will put oil in the cylinder and extend it purging air out of open port of rod side of cylinder. Shut machine down, connect hose to rod side of cylinder. Then pin the rod end to the boom. Move on to next cyl, same process. Be careful if it has 4 bolt flange hose connections, those puppies will spray you when you break them loose if pressure is on them.
LOL, done learned about those 4 bolt flanges. As I was explaining the dangers of air in a hydro system, I got a lesson myself in for form of an oil bath. There are drains on the flanges but if you don't use them, they don't work... Is there any danger of getting the full mouthful of air in the system to work back to the tank or will that prove problematic. I also have the rod side bucket cylinder line pulled. I would just crack the bleed bolt but the cylinder is looking down and not sure we will get much air out that way.
If you purge cylinders using method I described, not much air goes back into system. What little air is caused by breaking connections has little consequence.
When I do cylinders I install the barrel end pin, hook both lines back up, suspend them in some manner so the rod is free to move and cycle them slowly end to end a few times and then line it up to put the rod end pin in, haven't failed me yet.....
IMO you don't have to worrry too much about the air in a newly installed cylinder working its way back to the tank, but you DO have to worry about the oil level in the tank dropping so far the pump can start cavitating. I usually make sure the tank is over-full before cranking up the machine and exercising the cylinder(s).