Farmall 504 hydraulic problems

In order to do a pressure test, you will need to make a hose with a quick-coupler that plugs into your remote ports. That hose then needs to have a guage that will register at least 2000 psi and a shut off valve all plumbed in series. The other end of the hose needs to dump back into the reservoir. Run the tractor until it reaches operating temp. and work the lever that will send pressure to your test hose. Slowly close the valve just long enough to spot a pressure reading ont the guage and re-open the valve. You should get a reading of 1600 to 1700 psi.

Hydraulic systems need to operate in zero tolerances and almost sterile enviroments. It doesn't take much to plug something up. Good luck and let us know what you find.

Tom

I'm not comfortable talking about a 504's system. I just went through a 460's system-I'm faily versed on that. Just don't know how much different the newer series tractors are from their Daddy's. We have a 504, and it sure does look a lot different than the 460's at least as far as where the components are located.

If the problems you describe were on a 60 series tractor, I would agree that the relief is bad, but not entirely so. There's just not much that can go wrong. I suspect there's a chunk of crud partially holding the relief open, or the relief may not be allowed to seat fully (close) maybe from a scored bore or whatever.

With a no load condition--raising the loader with no weight--not much pressure is required for this, so most of the oil would rather go to the path of least resistance (a loader with no weight in the bucket)than through a partially cracked relief valve. With a weighted bucket, most of the oil would rather go screaming through the partially cracked open relief.

These symptoms should be the same with your fast hitch--no load,fine; with weight, squealing.

I looked at our 504's system layout this past week comparing it to our 460. It appears the relief/control block is located on (under) the draft control quadrant. The 460's hydraulic vitals are easy to access. Looks like the 504's would be the same.

Don't overlook the simple fact that you may have a pump that has seen better days. If internal pump rotor clearances have increased due to wear, the pump will develop enough pressure to lift an empty loader, but will holler at you when it's required to work hard due to oil bypassing internally. Our 460's pump was this way--it would barely lift an unweighted fast hitch.

I'm just speculating. Get a manual if you don't already have one.

Tom

The first thing to do is what you did--change out the filter and oil. This will eliminate any remote problems with the system associated with that.

The best thing for me is to email my brother and have him log on here and respond to some of these questions with manual in hand.

You're right! The 504 has a lot of hydraulics! Lots of plumbing! This is a reflection of the market trend in those days for upgraded and versatile hydraulic systems. This probably started with the 60 series.

I have had my 504 home for about a month and am experiencing similar performance. Power steering and 3-point hitch work fine. Went to check hy-tran fluid over the weekend and fluid is milky. I am wondering what this might indicate. Next weekend I am going to drain hydraulic fluid and refill with new.