Hydraulic pump problem bandit 90xp

[You know this guy!]

So here we go again with my lemon of a chipper. It never fails me at failing!!!!

Brush Bandit 90XP approx a 2005

When I feed a piece of brush in the feed wheels will slow right down and stop because it does not have the power to pull it through. After this the feed wheels will turn very slowly. This tells me the pump on the lower fees wheel is tired and needs to be replaced. I only think this because I have allready had the upper one rebuilt.
Does my diagnosis sound accurate and where would I go about getting a new one. I hear there are newer and better pumps out there so I am interested in replacing instead of repairing.
The hydrailic filter is brand new so it shouldn't be clogged yet so frankly I'm out of ideas

 

[kellytrimming]

I suggest verifying the hydraulic pressure coming into the feed wheel motors is within specification. You ought to be able to determine PSI from the owners manual, but I would guess it is around 3000. A gauge like this would work: http://www.northerntool.com/shop/tools/product_200322889_200322889 . If the pressure is lower than specification, the problem is before the feed wheel motors. If the pressure is at specification, the problem is at the feed wheel motors.

 

[Merle Nelson]

Yeah, motors on the feed wheels. Only one pump driving it all. (I believe.)

 

[kellytrimming]

Yeah, one pump at the engine driving 2 feed wheel motors. Pump turns engine rotation into hydraulic flow. Motors turn hydraulic flow back into feed wheel rotation at lower rpm, higher torque. https://en.wikipedia.org/wiki/Hydraulic_motor . Wiki says they are conceptually the same thing.

 

[tc262]

Proper diagnosis is key, don't just throw parts at a problem you are unsure of. Get some gauges to verify pressures before buying parts.

 

[LimbLoppa]

Check the directional valve( follow the lines from the feedwheels back) it's a big block. It just splits hydraulic pressure between the wheels. You can also check the belts to see if they are loose. A loose belt to the pump will cause the feedwheels to lose power too.