HELP! Did I do something really bad to my B7300?

[skent]

Here's what I be talking bout. . . . .Engine driven main pump (left side) sends flow to priority valve. Most of the oil goes to the hydraulic circuit for the 3 point lift, but 0.5 gpm goes to cooler along with flow from the hydrostat charge pump (but remember-its not turning if the clutch is pushed in) and thru filter and charges the variable displacement hydrostat pump. This way, all the goodies in the hydrostat can be lubed under pressure BEFORE anything in the hydrostat starts turning. This was a change they made to the newer B7300's like climber's and mine. Hope this helps.

 

[skent]

With all the hoopla I almost forgot. . . here's the change and new startup procedure. . .

 

[jrlichina]

The priority valve is used to give the power steering option priority over the tractor hydraulics. This is to make sure you can steer the tractor. It is not used to charge the HST circuit(although its excess when not used is routed to the cooler then the HST). The HST charge pump is devoted to keeping the HST circuit at full operating pressure and make up for volume losses. If power steering is added and the wheel is being turned all the flow(0.5gpm) goes to the steering. As long as the HST input shaft is turning the charge pump will be turning, helping pressurize the system. When no power steering is installed or when the wheel is not being turned it does help in pressurizing the system and oil return. Thanks for posting the flow diagram, it does help in conveying what the heck we're rambling on about. /forums/images/graemlins/laugh.gif

 

[skent]

One point you missed though - this model (B7300) does not have power steering. . . . .

 

[jrlichina]

I didn't say it did, but there was also no indication that it doesn't(posts don't state year or options). I just wanted to outline the purpose of the priority valve.