580SM Hyd Tank Top Plug

[Metalman 55]

I'm doing some repair work on a battery box/hyd tank on a 580SM & going to replace some rotted plate work for a local guy who owns the machine. We came across this pipe plug at the top of the tank & seeing that Im going to replace the whole plate between the battery & tank, we were wondering what that pipe plug is for, if anyone knows. I'm thinking it's not needed, as all connections are on the back of the tank for suction & return. Whats the verdict on this plug if anyone knows?

 

[Coy Lancaster]

That plug is usually used for auxiliary return, such as for a breaker. I used it to pressurize the hydraulic tank when I changed out the pump or changed oil.

 

[SlatcoAu]

I hate that design on these machines. Mine did the same thing. Battery acid ate the side of the hydraulic tank away and the tank started to leak.