The goal in changing and oil in machinery is to get as much of the old dirty oil out. There are a few things that you can do to ensure that you are getting the maximum amount of oil out of the system.
Make sure all of the cylinders on the hydraulic system are in closed position. When the cylinders are in closed position little oil is left in the components. This is also true for other expansion components located in the hydraulic system.
Some complex hydraulic systems have more then 1 drain port where you can drain oil from. The largest drain port should be located on the main reservoir, some components my have individual drain ports to remove remaining oil from low areas.
Also pull any return-line filters, these can hold a large amount of oil, and by removing them you can unblock the return-lines for additional draining.
When draining air must be allowed into the circuit to let any oil drain out. All breather ports should have breathers on them to filter out moister and debris.
Each system will have different ways of replacing and changing oil, but all will have the same basic steps.
1. Remove drain plug.
2. Allow oil to drain.
3. Replace filter.
4. Fill with new oil.
Get your OEM filters and replacements with Online Filter Supply!