TOTALLY OT for this Board... broken tractor pic 'o the week

John Deere 6420... under cab fire and failed inlet priority valve...

Been working my way through a big project replacing under-cab climate control ductwork and wiring and hyd hoses after a fire, and am now getting to replacing the "inlet priority valve" which has been causing hydraulic NOISE and heating.

Have a bunch more pictures to post when I'm done.

<img src = "http://i.imgur.com/BB6Z90e.jpg">
<img src = "http://i.imgur.com/E6O3YvV.jpg">

I'd be curious how the fire got going and especially how it got put out?

Loader tractor.

Chaff and debris under the cab and around the RH loader mount got lit of by the exhaust system that is mounted to the front RH cab pillar.

For better or worse, owner had a LARGE fire extinguisher handy.

Is your shop in 58324 or in the "B" town or on your farm? I was born in 58324 at the Howard Maternity Home long before the hospital was built. What model tractor is this? I grew up around 58365 but I believe you already know that.

Shopmis @ farm. Tractor is a 6420.

You probably know that if you need more room under the cab you can take the rear right wheel off and it will go further. Right to the floor further but I wouldn't recommend that!.
Also when you pull that valve apart be aware of the location of the "dime valves" between the components. If they are lost or are put in the wrong location you will have troubles.
Post a pic of the inlet priority valve when you get there. I am thinking it is cracked.

Yes, I am aware of the &^%* "dime valves".

We've been into the priority valve before and can seen nothing visibly wrong, but it seems to be leaking internally, from the pressure side to the "pilot" side, keeping the pump in stroke and not dropping to standby pressure after a function is used.

WORSE as the oil warms up/thins.

Sounds like you may have experienced some similar issues, perhaps?

Dealership has put over six grand into hauling, diagnosis and replacing the mid-mount loader valve, without solving the problem.

Sometimes the %&#^* thing won't even start because the hydraulic pump load is so great it throws black soot and soot and can't get up to speed unless you fiddle with a hydraulic function.

I have posted on the DEERE Board several times over the last 2 years asking if anyone has dealt with similar issues, without getting a reply.

SURE hope swapping out the PV fixes it. I won't know for a couple of days because I am waiting for a couple of oil hoses that are used in that area to come in.

Between the fire and the HOT hydraulics, we are replacing ALL pressure and return hoses under the cab and in the pump and valve area because they are SHOT!

I have heard of issues with the priority valve housing cracking and allowing pressure oil to leak in to the load sense circuit putting the pump in to stroke, creating the problems that you are describing here. I hope you are replacing the entire priority valve housing and not just the valve itself.

Jared

Yes, the whole unit is getting swapped out.

I will post back with the results in a couple of days.