Changing hydraulic oil

[MickeyB]

I have a Bobcat 328 mini digger and I want to change the hydraulic oil. It is an old machine (2001) which I have bought and I believe that it is currently filled with HF 32 grade. I want to drain and replace with 46 grade. Is it best to have the boom extended fully and the blade up so that the rams are closed as much as possible before draining the oil? I am told that you mustn't mix the oils and so I have to remove all of the old 32 oil. Do I also have to disconnect the pipes etc to remove everything as I am sure that there will be some residual oil in the system? Or am I worrying too much?

 

[Nearly]

@Mr Happy

 

[Lincs Lass]

Double acting rang rams have equal amounts of oil both sides ,,it wont matter if they are straight or folded in ,,just disconnect a pecker if its on ,,other than that ,drain away

 

[sulky]

Double acting rang rams have equal amounts of oil both sides ,,it wont matter if they are straight or folded in ,,just disconnect a pecker if its on ,,other than that ,drain away

not what i believe theres the displaycment of piston in the cylinder one way

 

[Lincs Lass]

not what i believe theres the displaycment of piston in the cylinder one way

When I was on plant job ,we had two 13tn,s 360 ,,dropped the hydraulic oil in both ,didnt matter which way the rams were facing ,40 ltr soon mixed with anything left in the system ,changed the filters and away they went

 

[MickeyB]

@Mr Happy

Double acting rang rams have equal amounts of oil both sides ,,it wont matter if they are straight or folded in ,,just disconnect a pecker if its on ,,other than that ,drain away

Thanks Lincs Lass, that's very helpful unlike Mr Happy!!

 

[Mr Happy]

@Mickey B it really won't harm a machine of that age mixing two different grades of the oil. To extract the maximum amount of old oil from your machine have all the the rams fully retracted. Also do a filter change as well and if possible a suction pump will help drain the hyd tank.

 

[MickeyB]

@Mickey B it really won't harm a machine of that age mixing two different grades of the oil. To extract the maximum amount of old oil from your machine have all the the rams fully retracted. Also do a filter change as well and if possible a suction pump will help drain the hyd tank.

Thanks Mr H!

 

[Mr Happy]

Thanks Mr H!

That's ok... why do you want to change the grade of hyd oil?

 

[MickeyB]

That's ok... why do you want to change the grade of hyd oil?

I don't really. It's just that I also have a JCB with 46 and it would be easier to keep everything the same. Also I initially tried to get the Bobcat 32 fluid which was specified in the manual and contacted a couple of dealers but couldn't get any - and they told me that they just used other 32 oil instead of Bobcat's. A bit of a minefield all these different oils for the novice!

 

[Mr Happy]

That makes perfect sense to me, keeps life simple to. Hydraulic oils are a bit of a mine field but your oil supplier should be able to help with information or contact your local hydraulic company.

 

[76masseyman]

The only thing to watch for, and I’m presuming the digger hydraulic oil is also used to drive the track motors, is ensure the oil meets DIN 51524 pt 3. Get yourself a good quality HLP, HV or HVI 46 grade, and use that in the JCB also.
A standard spec hydraulic oil will overheat if you do a lot of travelling on the running gear. I think Bobcat mainly spec’ an ISO 46, but as an SAE 10w/30 grade transmission oil for this reason, similar to JCB Robot.