Symptoms of a weak hydrolic pump??

   / Symptoms of a weak hydrolic pump?? #1  

Whitetail

New member
Joined
Jun 14, 2012
Messages
3
Location
Landenberg, PA
Tractor
JD 410B 4x4
1984 John Deere 4x4 backhoe 410B with 5700+ hours....My question is; when it's already warm and you try to lift the front bucket there is a hesitation and shudder; and then it will lift. Also when you drive it on the road in "high" the brakes have to be pumped 1st in order for them to work - then work great (brake pressure gets lost for some reason). Could these 2 issues be related to a weak hydrolic pump?
 
   / Symptoms of a weak hydrolic pump?? #2  
I have to ask, have you checked the basics first? Check the level of the hydraulic fluid? Replaced the Hydraulic filter? If neither of them fix the problem replace the fluid (unless you know it was done not too long ago). I don't know JD but I can find no reason why the brakes would be tied into the tractor's hydraulics.

Pumping the brakes are usually a sign of air in the brake lines. As long as the brake fluid isn't dropping I would say all you need to do is bleed the system.
 
   / Symptoms of a weak hydrolic pump??
  • Thread Starter
#3  
I'm not that familiar with JD either (more familiar with CASE); this one was recently purchased from a state township. As far as I know the brakes are in the hydrostatic transmission; and the fluid was replaced not too long ago (though it is slightly over filled). Don't know if the filter was replaced when new fluid was put in. Thanks for the suggestions.
 
   / Symptoms of a weak hydrolic pump?? #4  
I believe this model JD used a priority flow control to supply the oil to steering and brakes. Don't remember the circuit exactly but I believe the brakes circuit also had a pressure reducing valve in it to control the pressure to the brake circuit. If this valve is getting sticky it could cause the symptoms you decribe.

Not sure how or why pumping them would help build pressure since from memory they had a constant flow and pressure source.

On the 4 x 4 versions the filter is a real PITA to access and change. I would take a good look at the filter housing to see if it looks like any one has changed the element.

Does the BH run OK?
 
   / Symptoms of a weak hydrolic pump?? #5  
Why not put a hyd gage in the circuit and monitor the hyd system. Check relief pressure.

Hesitation could be caused by air in the cyl.

Cycle the lift and bucket cyl about 5 times until the relief goes off and that should purge any air for the moment.

If you do have air, you could have a suction leak. Check tank for bubbles.

A relief valve might have some debris under the seat and heating up the fluid.

Is your hyd system open or closed center?
 
 
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