nh 7840 hydraulics

[dave7840]

Having some hydraulic issues with our 7840 sldp. its been sat on the straw chopper all winter and once in a while the steering would get slightly heavy on idle, but no other problems. So now we have started silage I changed the backend oil and filters, thinking that should stop it happening again and everything was working fine, till about an hour into tedding when the transmission pressure light came on and the steering stopped working. I checked the oil level, fine and the filters, fine. So I folded the tedder and lifted it up and went to head back to the yard and had no drive, so double checked the oil and filters, all fine and tried again and she drove again, so got her to the yard. now I'm guessing its one of the pumps. the linkage and services on the back work as normal. so is it the main pump or aux pump.

 

[fermerboy]

Main pump is a tandem pimp, one side does lift arms and trailer tipping. The aux pump on the engine helps out with extra for the spools. The other low pressure side of the main pump does steering operates the clutch packs and pto. Pump likely worn out, not a bad job or that expensive either. Could be the pressure control valve which is part of the pto pack but depending on hours it's likely to be the pump. Get a pressure gauge on it .