JD 4120 Hydraulic Failure

[bigforkphil]

My JD 4120 Power Reverser has no hydraulic pressure. Changed the filter, the fluid(it was cloudy) and cleaned the two screens as described in the owners manual. I still have no hydraulics working. Any suggestions? Is there anything else I need to check/do? Thanks.

 

[beenthere]

:welcome: to TBN

Tell us a bit about what took place before you discovered no hyd. pressure. And how are you measuring the pressure that you have now?

 

[arlen4720]

Does the power steering work?
Does the 3 point work?
Does the tractor move?
Does the loader work?

 

[bigforkphil]

Does the power steering work?
Does the 3 point work?
Does the tractor move?
Does the loader work?

I was using the loader and it started becoming jerky, then squealing, then not working at all. Shut it down, checked hydraulic fluid(cloudy, but full). Changed oil and filter and cleaned screens(they were gunk'd up). Now have no loader, 3 point, steering, or transmission. I'm thinking pump failure and a trip to the dealer is next, unless someone can give me another item to do/check. I have no way of checking pressure other than disconnect at various places and see what happens when I cycle that part. So far no blast of oil from anywhere.

 

[arlen4720]

Since the steering uses a separate pump than the other hydraulics, you may have sheared the common drive pinion to the stacked pump assembly.

 

[Trucker1]

Since the steering uses a separate pump than the other hydraulics, you may have sheared the common drive pinion to the stacked pump assembly.

Not to hijack here, but my 4510 has the same symptoms when I started this morning. None of the hydraulics or power reverser work. Fluid is nice and clean, and was working fine when I was running it last Saturday. I am getting some pressure from the vent breather on the rear axle. I also had some oil puke out of the rubber manifold on the pump when I shut the engine off.
Any additional thoughts would be appreciated.

 

[arlen4720]

I also had some oil puke out of the rubber manifold on the pump when I shut the engine off.

That is the suction line. It may be compromised and pulling air in.

 

[bigforkphil]

Thanks all. I figured that this is a major issue and got the beast on a trailer. Dropped it off at Sunshine Equipment. I'll post the diagnosis and estimate when I receive it.

 

[bigforkphil]

Hydraulic pump needs to be replaced. parts, labor, filters, oil etc. Parts and labor about $1700. I wish it was less!

 

[DFB]

Maybe it makes you feel better owners son blew out the hydraulic pump on the JD2855N at work

Check out the replacement price on that new!

John Deere Hydraulic Pump - AR103036