HST Hydraulic Fluid Drained VS. Capacity

[TN8Man]

I just did my 400 hour maintenance and was expecting more hydraulic fluid to be drained. My capacity is 11.89 gallons but what drained was about 10 gallons or slightly under so about 2 gallons less than capacity. I did have all the hydraulic cylinders compressed.

Is this normal?

 

[LouNY]

You will never get all the fluid out, there is a lot held in the hydro pump and motor. Plus whats outside the main hydraulic pump, lines and cylinders. Even with your cylinders retracted the other side of the piston is still full, plus your steering pump and system.

 

[RjCorazza]

It's normal on my last 2 Kubota tractors. Mine seem to retain maybe a gallon on a fluid change, but I don't bother measuring it anymore.

 

[oldnslo]

Did you pull all the drain plugs? On my Branson there are three plugs, the main one gets vast majority out other two drain low spots on the trans-axel housing. Even then I never put in what manual states it should hold.

 

[TN8Man]

Did you pull all the drain plugs? On my Branson there are three plugs, the main one gets vast majority out other two drain low spots on the trans-axel housing. Even then I never put in what manual states it should hold.

That is a good question. My manual says to remove the drain plug on the bottom of the transmission to drain. Then it says "If the fluid does not flow out freely, unscrew the plug on the side of the hydraulic cylinder on the left of the top link bracket to facilitate drainage."

I do however have two drain plugs (painted red) on the trans-axel but the manual never refers to them.

My manual also claims the HST hydraulic capacity is 14.6 gallons but my shop manual claims its 11.89 gallons which seems to be correct.

 

[dcsco]

I just changed hydraulic fluid on a dk5510. Capacity is 11.xx gallons and it took about 9.5 to refill.

 

[TN8Man]

I just changed hydraulic fluid on a dk5510. Capacity is 11.xx gallons and it took about 9.5 to refill.

Thank you, this is helpful. I was thinking I should drain a gallon or so from each low-point drain port on the trans-axel and then add back fluid. But since people are reporting they typically don't get full capacity out at about 1-2 gallons I'm thinking it might not be worth the effort.