Changing transmission/hydraulics oil question.

[twomanyprojects]

Have an old L225, and I don't like the look of the tranny fluid (who knows, might be the original.....) I have drained it but am thinking about how to push all the hydraulic fluid out of a backhoe on the tractor. I'm probably going to disconnect the return line and see if I can catch everything so it does not contaminate the new oil in the tranny.

My question is, if all the backhoe controls are neutral, does the oil recirculate back into the tractor tranny, or does the valves shut off the flow and the pump just work against a regulator valve to maintain a constant pressure?

I plan on disconnecting hoses to excercise each cylinder and push out as much old oil as possible.

Thanks for any suggestions

Frank

 

[Blkvoodoo]

I recently took ownership of a B2400, and I will be changing the trans/hydro fluid in it soon.

Mine has a loader on it, not a back hoe, but the control valve workings should be similar. the control valve is flow thru, and the spool valves divert fluid as needed.

My plan is to drain the trans, replace the screen and filter, refill, let it run for a few minutes, then work the hydraulics several times, and drain it again and refill. I doubt I'll use Kubota fluids, as they are quite spendy compared to TSC or AgriSupply.

Unfortunately double acting cyls trade equal amount of fluid end for end when they work, so you always have a residual amount of "old" fluid in the system, more so than what you would have in the lines alone. getting it ALL out would require some disassembly and time ( and mess )

and be VERY careful disconnecting hoses, know damn sure which hose is holding the weight of what you are working on, one wrong wrench turn can be quite harmful ( or deadly ) to the wrench turner.....

 

[kuboman]

One way to get the oil out especially with a loader is put the loader in the high/extended position. Drain your oil and then with engine off of course let the loader down to the ground. That will push the oil out of the lift side of the cylinder and with the engine off there will be no oil pumped to the down side of the cylinders.