843 Pump Rebuild wont move

[rockypool]

I just replaced a rear Hydrostatic drive pump and I have lift and tilt action but no drive motion I put in new filters and cleaned the cooler so lots of air I guess I have lifted and run it several times but no indication of flow to wheels Its an Isuzu 843

 

[J_J]

Did you bleed all the air out of the pump. On most hydrostats, there is a bleeding procedure. On my hydro, you disable the engine, and turn a bolt that opens up a set of relief valves on the pump, and fluid can pass through the pump. We connect a hose to the input of the hydro, and bleed the air out of the hydro, until no bubbles are presents.

You might also have a charge pump with a pressure around 350 to 450 psi.

We do this on out machines when we change out the filters, and or pump/hyd motors.

We also have 10 micron hyd filter on the input to the charge pump. Check the charge pump pressure.

 

[wdchyd]

Rockypool,

Not sure of what pump you're talking about but hydrostatic drive pumps need the case to be filled BEFORE start-up........whoever sold you this pump should have told you where to prime it......

If it's a piston pump severe damage can occur if not properly primed and bled within minutes (or seconds in some cases)

Another tip that you should do is raise the unit off the wheels/tracks to allow all air to purge out while performing start-up procedures.....also for safety if the machine decides to move.......

Pics would be helpfull......