4720 Power Steering has hard spots when turning quickly

[Brown Dog]

If I turn wheel slowly, it's ok.
But turning quickly - it has hard spots in it.
Can the pump have air in system OR can the pressure or volume be increased ?

I'm running throttle at 2,000 rpm's, because I'm Mowing in E-PTO setting.

Specs shows this 4720 P/S to have more flow than my older 4700, but the 4700 doesn't do this.

Any ideas ?

 

[fuel doctor]

If I turn wheel slowly, it's ok.
But turning quickly - it has hard spots in it.
Can the pump have air in system OR can the pressure or volume be increased ?

I'm running throttle at 2,000 rpm's, because I'm Mowing in E-PTO setting.

Specs shows this 4720 P/S to have more flow than my older 4700, but the 4700 doesn't do this.

Any ideas ?

Have you checked the screen in the transmission , changed the spin on filter .

 

[arlen4720]

Have you checked the screen in the transmission , changed the spin on filter .

and don't forget about the filter on the high pressure side of the power steering pump. It's supposed to be serviced every 600 hour or so IIRC. How many hours on your machine?

 

[Brown Dog]

I've just bought the tractor & it only has 250 hrs on it.

It still has original fluid & filter.

I mow strait runs, turn around & go back on 12-14 acres.

It's aggravating :-(

 

[mfreund]

I would take the hydraulic cylinder loose from the steering linkage. If it still did it then it is hydraulic related. If not it would be in the steering linkage.

 

[Brown Dog]

I think I'll chk the screen in p/s side of pump
Thanks Arlen

 

[jcalla]

Charge Pressure Line (from SCU (optional through oil cooler) to Transmission) has a flow filter. It is located just before it goes into transmission.
JPC

 

[Eric102]

Are you in 4 wheel drive? That can cause some binding in the drive train on tight turns that can feel kind of jerky.

 

[Brown Dog]

I'm in 2wd.
Where does this line with filter, go into the trans ?
I hadn't had time to diagnose.

 

[oldnslo]

Jerkyness in steering can be caused by lack of pump flow. Not familiar with your JD models but parts breakdown shows a double pump so would suspect one section supplies the steering. Did JD use a different size steering unit on the 4720 Vs 4700.

If you run the engine RPM higher the problem still exist?

Does the steering wheel kind of lock up and then turn again or kick back and then turn again?