Hydraulic fluid change, cylinder drain/bleeding? B21

joea99 · Apr 12, 2017

Having just resealed a couple cylinders, am about to drain fluid and replace filters.

No doubt this has been covered many times. If so, just point me to the right place. "Friendly local Kubota dealer" does not count. Transport being the obvious reason. Being a cheap so and so is the other.

For the filter change, I was going to "pre charge" the filters as I do when changing engine oil as it cuts down the time engine is running with no oil. That is, pour oil into the filter till it does not soak up any more, then invert to drain excess since most engine filters install holes down or to the side.

The work shop manual does not mention draining the cylinders, but that seems prudent to me, so as to not mix old with new. So, is it a good idea? If so, I fully expect some air lock at some point, some where. The manual mentions bleeding, but has no examples.

KennyV · Apr 12, 2017

If you don't mind putting the extra effort into draining all the cylinders, no problem... Most just consider the percent of residual old oil as compared to the complete system, as being too insignificant to justify the time and effort...
as for bleeding the air, when you activate any hydraulic circuit the oil will flow in and displace the air shoving it out and eventually into the main tank where it will vent. so no problem with air. KennyV

joea99 · Apr 18, 2017

Managed to get them resealed, (or packed if you prefer), fluid and filters changed. Gave me a scare when I fired it up and had no hydraulics at all. After a few top offs and restarts, decided I was babying it and got the revs up to normal, then heard "something" happen and the hydraulics began working.

A plus - nothing is leaking. So far.

100 td · Apr 19, 2017

You drained the axle housing bungs as well?

joea99 · Apr 19, 2017

100 td said:
You drained the axle housing bungs as well?

There were 3 drain plugs for the hydraulic/HST fluid change. The front I just drained and refilled with gear oil from Walmart. That looked like it had never been changed.