I have a dump truck that used to be a plow truck with a front driven pump. I don't use it a lot and not much below -10C. The sight gauge is a little cloudy so I wanted to add 5L of oil just to be safe. I picked up some ISO AW46 ( SAE 15). I don't know what's in it now but looks like clean standard light brown oil. Should the ISO AW46 be OK just to top it off?
Have you smelled what is in there now? should be easy to smell the difference between 46, straight 30 and a few others.... unless someone already mixed up a cocktail
On something used how would know what was put in it or if oils were mixed? You should be very rich if you can smell oil and tell exactly what grade and type it is. It's not an odd color which leads me to believe it's standard hydraulic oil. Just wondering if adding 5 litres of ISO AW46 would hurt anything.
yes, would be very rich!!! Certain oils are fairly easy to smell difference, but you are right if they have been mixed then it's anybodies guess... On older stuff that doesn't get used that much I wouldn't have a problem dumping in some aw46 or tractor fluid with decent ratings.
With a gear pump and just cylinders in that system, AW 46 is a good choice. As long as it's oily and not to heavy, it's bound to be ok. If it was high pressure piston pumps or fed to clutches and wet brakes... that would be a different story.
I put it in. It's a pretty big hyd. tank so I didn't think 5 litres would affect it too much if the other oil was conventional oil which seems the most logical. Oddly the new oil was a clearer color. I think the system operates around 2000 PSI but I'm not sure if it's a piston pump or not driven off the crankshaft. I think it may be a piston pump though because there are more than just an inlet and outlet on the pump. Maybe it's a 2 section pump? It has about a 2" inlet and about 3/4" outlet on the end but on the side there is another 3/4" line and a small maybe 3/8" line on the bottom connected to what looks like some kind of valve. Maybe one of the lines is a case drain? I think the small line on the bottom could be for pilot pressure because the valves are electric solenoid and need pilot pressure to operate. The small line looks to go to the control valve as well as one of the 3/4" lines. The hoist valve doesn't always want to operate and I'm wondering if maybe the valve type thing on the bottom of the pump with the small line is gummed up and sticky?
A pic would help. It's probably a gear pump with a "dry valve" Dry valve allows enough flow to lube the pump until you hit a switch to raise or lower the dump bed or operate a sander or plow... if it's the setup I have seen.
It was originally a Rexroth Compu-Spread system. Now it just has the dump box. The speed of the hoist is constant and doesn't change if the RPM is increased. It's kind of annoying the solenoid valves don't always work and you have to keep trying the switch. I don't know if the problem is with the solenoids on the on the control valve or with the valves getting pilot pressure. I talked to one place and they said I could try changing the solenoids with ones on the now disconnected valves and see if it works consistently. Disconnecting the wires I get 12 volts with the switch activated so I kind of ruled out the switch as the problem. That's why I'm thinking maybe the valve type thing on the bottom of the pump with the small hose is maybe sticking. The cylinder is single acting but the valve has a large and the small line from the pump going to it.