Hydraulic pressure low when oil is hot, B8200

oldbeek said:

When I work my tractor hard the hyd pressure drops. Start next day when cool, everything seems ok. Is there a tap point to check pressure? My manual shows hooking up a pressure gauge with a bypass directly to the main pump. Seems like a relief valve problem to me.

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First off - as the fluid is cold it will pump up to a higher psi, as it warms the pressure will drop off. I think everyone that works a bucket or hoe will see that over time of the working of the hydraulics will lessen to a point that is seems a little less. Think of it this way, most men/women take a blood thinning to LOWER the BP through the body, the thinner blood drops the BP (aka psi) - now there is a reason for that - blockage in the system. Your machine doesnt have a blockage but rather a liquid that is "easier" to pump, thus the psi will fall off.

You can change the oil, that may help for a while. When was it changed last and what type was used? And you can check the pressure too - that will tell you exactly where the difference lies. ON my new bx ( 100 hours ) I shimmed the bypass valve with the prescribed washers. What a difference!!!

Others will tell you where the shim if that is what you wish to do and where to check - usually you tap in right at the hose disconnect - allow the machine to get to working temps, uncouple - snap in gauge and check.

Not sure what the psi spec's are on the B series. I am sure others will know!
report back and tell us what you find out

There are several things that could be involved.
When was the last time you changed filters and fluids?
What type of fluid did you use?
Do you have a loader on it?
How many hours are on it?

While changing the pressure on the relief valve may bump the pressure up, it most certainly make up for a worn out pump or a plugged pick up screen/filter which is the #1 reason for hydraulic system problems.

oldbeek said:

I used Tractor Hydraulic fluid which is pretty much universal brake, clutch and hyd fluid. 500 hrs on machine. The pressure is so low that it will barely lift the bucket. I will plug in to a QD and ck press. DAA! I was over thinking the procedure. I have a shop manual with the specs.

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With 500 hour on that old of a machine, I would check for a dry rotted suction line that is sucking in air to the hydraulic pump.

Go take another look at it, it's not all metal.