Hydraulic problem

[scottkin]

OK, now I really need some help! I was using my tractor's FEL to move some topsoil on my property near my concrete driveway and noticed the last few loads/trips had dribbled fluid all over the driveway.  So, I figured I had busted a hydraulic hose.  NO SUCH LUCK.  I wish it were so simple.  My 354 had started leaking hydraulic fluid out the top of the three-point hitch reservoir.  So, after parking it and looking closer, it was at the very top near the fill point, and after closer inspection it was oozing out of the vent holes in the fill cap.  So, I unscrewed the fill cap and looked at the dipstick and noticed I was a little low on fluid.  An obvious discovery after some leaked out.  I purchased some AW32 fluid and was going to top if off and decided I might better get some help before messing with something I know nothing about.  So, I picked up the phone and called Thomas at Affordable Tractor in Texas.  He asked if I was working on a slope and I said yes, I was.  He said these tractors will leak out some fluid sometimes simply from working on a slope.  So, I was excited that might be my only problem.  Not so.  A day or so later, I started the tractor and disconnected my bush hog in order to be able to work on the machine and noticed about 1-2 minutes after the tractor is started, the fluid just starts to ooze out of the fill cap vents.  This time I got a closer look and the fluid is VERY foamy.  Almost frothy like a capuccino.  So, I called a friend of mine that is a diesel mechanic and works on tractors all the time and he said it sounds like I have air being introduced to the hydraulic system somewhere.  I checked several obvious things like the tightness of the hydraulic filter and checked everywhere for leaks and could find nothing obviously wrong.  He said many tractors, John Deere tractors included, have a secondary filter down inside the transmission of the wire screen type that sometimes get clogged.  Also, my front end loader is moving much slower than usual and "bumpy" as it goes up and down, speeding up and slowing down.  My three point hitch arms on the back can be raised or lowered by hand with no resistance.  Do any of you have any idea where I should start to remedy my sick tractor???  Thanks in advance for your kind help and consideration.

[Rich Waugh]

Yep, it sounds like your system is sucking air in someplace. Since that can only happen on the low pressure (return) side of things, that's where you start looking. You'll probably need to pull the top off the lift box and check out the filter screen on the intake pickup for starters, as that is the most likely culprit as your mechanic friend noted. I'd suggest draining the hydraulic fluid to start with, and filter it so you can see what sort of crud comes out, if any. Then refill it with kerosene or diesel fuel and cycle all the hydraulics a few times and drain that back out, again filtering it. Then pull the top of the lift bos and check out the pickup screen and piping. My guess is that you'll find the pickup screen collapsed.