At the start of the covid crisis I bought a 1959 Case 420B Tractor/bucket backhoe. I bought the usual Operators/Service & Parts manuals . When changing the fluid for the bucket/backhoe , It was very thin hyd. fluid that came out. But according to the Case manual it should have been SAE 10W--40 (PAGE 110). Obviously over time someone swapped/changed this to Hydraulic fluid . But Now I have no clue as to what the last owner used i.e. viscosity thermal stability anti wear etc... Just wondering what would be a recommened "safe" Hydraulic fluid to use up here in the northeast all year round. Thanks Dakota JIM
Welcome to HEF, Jim ! Not a problem as long as the oil meets Case specs. AW46 would be my choice for an alternative for the 10W-40. I am curious how you determined it isn't 10W-40.
easy just by the smell , cant mistake that smell
You could use the 10W-40 that case specifies. Tractor Supply has a decent price on it. Or AW46 that meets Case specs. I have used a generic brand of it for years with no problems. A complete system flush would need to be done to purge all the oil that is in it now. Simply changing the oil in the reservoir is a waste of good oil.
I agree. The Case manual states that the whole "system" holds 12 gallons for all the hoses/bucket & backhoe. It doesnt really tell the owner how to drain all the fluid left in the hoses/pistons etc....Just how to drain it from the reservoirs .And I am NOT going disconnect the lowest hose and start the engine to drain it --(As someone at work suggested) -As this would burn up the hyd. pump. What would be the right procedure to get at least 90% of the old fluid out. Tinkerer Thanks again for all your help.
The procedure should be in the service manual. If not - let us know. It is mostly the same for all Case T/L/B's.
I don't remember seeing it, but I will look again when I get home from work