Hydro fluid drain and fill on Bobcat zt225

killshot1

LawnSite Member
Hey guys, id like to do a hydrostatic fluid change on a bobcat zt 225. model# 942233a 61 inch deck with 25 hp kawi. Drive system is parker 12 cc variable displacement piston pumps with motors.

I have a manual for the fluid change but it seems to lack details and mentions nothing about having to purge the system so i am a bit weary to do it.

Manual says to: drain reservoir, clean and replace plug, change hydraulic oil filter, then fill reservoir with fresh oil to the bottom of the reservoir filler tube using specified oil type. says not to overfill...

I think this is an older commercial grade machine but i would like to do it properly. I did read somewhere on the lawnsite forums that it is beneficial to fill the hydro spin on filter as full as possible before reinstalling to reduce the amount of air getting into the system.

Is their anything else i should do during the process? Should i be concerned about air in the system even if the zt200 series manual doesn't mention bleeding them?

TIA
 

rixtag

LawnSite Senior Member
Location
Lehi Ut
From recent experience I can tell you that filling the new filter before installing it will cut down on the amount of air from that part. Make sure to keep the level up as well.
 
OP
K

killshot1

LawnSite Member
ok sounds good i will def fill the filter up before install.

What do you guys think is best for fluids? Manual says 15w40/20w50 or 15w50 synthetic. I run synthetic oil in my pick up but is dino oil better for these hydros?
 

rixtag

LawnSite Senior Member
Location
Lehi Ut
If the manual is specific, be specific with it. If it's easier to run the same weight and keep it synthetic in both then do it.
 
OP
K

killshot1

LawnSite Member
i agree. like i said i usually run synthetic in my cars/trucks but wasn't sure if this was a real benefit for hydro systems. I read somewhere on the lawn site forums that dino oils may be better for the seals in the pumps because of additives. add to that im not sure when the last fluid change was done or what type the previous owner used. I think there would still be fluid stuck in the pumps after i drain and fill the reservoir so i would have to take a chance on something and hope that it matches
 
OP
K

killshot1

LawnSite Member
Luckily on mine i did not have to bleed the system. just drained, pre filled filter and reinstalled and topped up and so far it has worked great. I did exactly as the manual stated to do, so if you have one try to use that just to be sure.
 

Forerunner Lawn & Landscp

LawnSite Member
Location
Ohio
Ok. Thx. My manual also states nothing about bleedng, although my filter installs directly into the oil tank horizontally. Dont think I can fill it much. Prob have to bleed off some. Thanks again.
 

BigFish

LawnSite Fanatic
Location
chesapeake, va
Look, when ya fill an oil filter, ya need to let it sit fer a bit so oil seeps thru the filter media, then slowly top it off.
Put yer thumb over the center hole and slap that sucker on the nipple. gonna lose some, but if yer quick, not much. Do a couple dry practice runs.
Oh yeah, have rags handy or make a catch pan.

Ya may even be able to unbolt the tank fer a better approach .

Also, horizontally speaking, it's best to let it sit a while to let any trapped air bubble up/out. Do it in the eve., let it sit overnight if ya can.
 

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