John Deere 4020 hydraulic pump

MY dad has a 4020 D. When its cold the power steering, brakes and lift arms wont work till it warms up.Where is the pump? does it have a filter that maybe plugged or does the pump need a rebuild when I find it.Any help will be great Thanks, Ray

There are two hydrualic pumps on a 4020. One is in the tranmission and supplies oil to the front pump which lies between your steering bolster and under your radiator in the front. If the pump in the back is bad the one in the front will not work properly. You may be able to tell if you hold the clutch in for a while it will shut trans pump off if you lose hydraulics then the front is probably weak. The real way to tell is have the supply line checked with a flow/pressure meter that supplies front pump. If rear pump is weak you need to pull top cover and 3 pt cover to get at it.

Ryan

There is a hydraulic oil filter(or two if powershift transmission)down on the left side of the transmission case. Try changing that first. There is also a suction screen located towards the rear of the tractor behind the oil filter. That may need to be pulled out and be cleaned, but the transmission oil will have to be drained first.Hopefully it isn't plugged with bits of brake lining.It usually takes a 1/2" breaker bar to get the plug to the screen out. Disengaging the clutch stops the charge pump frompumping so keep your foot off the pump as much as possible.

It's not unusual for this to happen, some times the operater will keep the clutch pedal down after starting the engine,,this makes it worse, if the hydraulic's work okay after it gets primed updon't worry to much about it, sorta like grandpa getting up out of his chair,a little slow at first then he's okay...

The hydraulic systems of the side console and pre side console tractors are quite a bit different. The pre side console tractor depends on a check valve deep in the transmission to keep the front oil cooler and reservoir filled. Many have worn out. In my I&T manual to check that valve is to destroy it. I found there was a JD service information about converting an elbow to a new check valve. I have created a web page about it.

When that check valve is bad, hydraulics (including steering and brakes) are lost with the clutch pedal pushed.

My '68 gas 4020 had that problem. I fixed it several years ago and it can sit for months, I can start it with the clutch pushed in and lift the loader without running the transmission pump at all.

Side console 4020 seem to have more problems from pressure leaks than a failed check valve.

The front pump is expensive to fix, and it seems like its most common failure is a cracked case that is not fixable. That shows up with a puddle of oil under the pump.

Changing the filter and cleaning the suction screen and making sure there's really oil in the system, not oil plus water are the first steps to be taken.

Gerald J.
4020 hydraulics loss

How cold is it? How long does it take to warm up? Are there any unusual noises that come or go? Are there any hydraulic loads added or connected to the tractor? Tractor serial number and/or style/year?

The installation of the aux. check valve that Gerald J. suggests will cure the symptom of hyd. pressure that is slow to build upon intial start up BUT if you are finding rapid loss of hyd. pressure whenever the clutch is depressed(syncro-range only) an internal leak within one or more of the hyd. valves back to sump may exist(internal leakage within the SCVs, steering valve, PTO valve, rockshaft valve, brake valve, etc.)...................