Power Steering GPM Flow vs Total Implement

Engine66 · Aug 7, 2008

I have a 4720 w/ehydro and was wondering if the power steering pump and implement pump are completely seperate or if they are inline together as one circulatory system? I recently had a rockshaft valve replaced under warranty that was making a harmonic whine in the the 3PH. I also had a transient vibration and whine from the steering wheel. Dealer said the system was one and the same, but brochure/literature shows PS pump at approx 5 GPM and implement pump at 11+ GPM. So question is, could the PS pump be causing the vibration and whine? This problem is very minor and does not affect the operation...it's just something I have noticed when I work the tractor hard clearing some land. I did read some others with same tractor say they too had similar sounds, etc with PS. Any thoughts? I'm at about 65 hours and otherwise the tractor is a BULL.

TedLaRue · Aug 8, 2008

Engine66,

Your 4720 has back to back pumps for the power steering and the implements. They are driven by the same gear, share the same hydraulic supply line, but have separate sets of gears and separate output lines.

I won't venture a guess as to the cause of your whine or vibration. I'll assume that you know that you'll get some whining from relief valves when you try to do something the hydraulics can't handle. Shouldn't be any vibration from that, though.

As a warning, your pump costs $514.50, and it appears that they don't sell any parts (like seals, for example) for it, only the pump as a unit. So think twice before you disassemble it!

Engine66 · Aug 8, 2008

Ted...thanks for the very informative info. I'll double check with the dealer on this vibration in the steering wheel. Regards...

ddivinia · Aug 9, 2008

Engine66 said:
Ted...thanks for the very informative info. I'll double check with the dealer on this vibration in the steering wheel. Regards...

My 4720 had a vibration in the wheel. There was a tech update on doing some isolation of the column, etc. NOte: It was worse when it was cold. It did not fix it 100% but it is acceptable now.

D.

Engine66 · Aug 9, 2008

ddivinia said:
My 4720 had a vibration in the wheel. There was a tech update on doing some isolation of the column, etc. NOte: It was worse when it was cold. It did not fix it 100% but it is acceptable now.

D.

D,

I recall an earlier post where you had a similar problem. I wonder if the pump is the problem or is the column the problem. When you say isolating the column, do you mean they insulate it at connection points to dampen the vibration...kinda like how motor mounts isolate vibration? Bottom line is, what is the vibration's source...pump or what? It feels to me like the pump, but I am no expert and still new to the 4x20 series. I will call my dealer Monday about what you said. Any other info you can share would be helpful...my dealer has been really outstanding...thanks!

ddivinia · Aug 9, 2008

Engine66 said:
D,

I recall an earlier post where you had a similar problem. I wonder if the pump is the problem or is the column the problem. When you say isolating the column, do you mean they insulate it at connection points to dampen the vibration...kinda like how motor mounts isolate vibration? Bottom line is, what is the vibration's source...pump or what? It feels to me like the pump, but I am no expert and still new to the 4x20 series. I will call my dealer Monday about what you said. Any other info you can share would be helpful...my dealer has been really outstanding...thanks!

I did not change anything on the pump or hydraulics. I believe the issue was vibrations from the hydraulic system into the column/wheel. JD Engineering has a service bulletin on it.

D.