310b slow hydraulics

[xfbi]

I have a 310 b backhoe. The loader got slow and then quit working. The hoe assembly continued to work and then it too quit. I changed both hydraulic filters and it worked again briefly and then slowed and quit. The outriggers will barely lift the rear of the tractor. Some times the steering works sometimes it get hard to steer. Next I removed the horizontal filter and its assembly. I removed the screen which was plastic and nasty much goo. I replaced with brass screen and was excited that now it would work I had planned much. but the hydraulic functioning is still the same. Nothing in the loader hydraulic and slow in the hoe. there were some metal shavings in the hydraulic reservoir when I replaced the screen. I got out all I could with a magnet and a shop vacuum. Before the tractor hydraulic shut down completely the system worked for several weeks with a shutter when raising the loader. she has always driven forward and reverse just fine. I would be grateful for any help. Fortunately I have a spare tractor I can harvest parts from to get this one working.

 

[LJD]

My first guess would be some debris stuck in the stroke-control valve in the main hydraulic pump. All it takes is a little speck to hold it open and you lose all the hydraulics.

Of course, you have to make sure the front pump is getting oil from the transmission pump. The main pump up front, unlike a gear pump, cannot draw oil to itself. It MUST be fed oil. Pressure is not important, just delivery of oil. Unhooking the input line and running the tractor for a few seconds is a good enough test. 5 gallons a minute is plenty. If a 5 gallon bucket gets 1/4 full in 15 seconds -you're OK.

 

[buickanddeere]

The nasty goo could be the brake disks if the brake friction
material has worn through.
There is a wee filter in the front pump inlet.
Time to flush every line and cylinder and refill with new Hy-
Gard.

 

[Tx Jim]

You could try installing(if not already present) and utilizing a destroking screw in hyd pump. If there is debris in destroking screw sealing area as LJD suggested opening & closing of the seat area of the valve might clean it out.
Parts key #6 AR96625 FIELD INSTALLATION KIT, SCREW, HYD ADD 15.01 USD