JD Seller RE: 4440 HFWD???

Tx Jim · Apr 28, 2016

JD Seller
Please explain your statement that follows & I'll quote your statement.

[/quote]

My understanding of a closed center hyd system is that output of frt hyd pump can be capped off with no ill affects to pump.

I understand capping off hyd oil to frt axle motors can be detrimental to motors.
Thanks,Jim

Bob · Apr 28, 2016

As to the motors, correct me if I'm wrong here, but when there is no hydraulic pressure to the brake pistons the "brake plate" in the wheel planetaries is released, and the hub is able to freewheel without turning the motor, so if you capped the lines to the wheel motors there's be no issue, the motors by then are effectively disengages from the hubs.

Mike M · Apr 28, 2016

Why would that front axle motor need a brake ? I'm doubting it has one.

Bob · Apr 28, 2016

Mike, the "brake" locks the ring gear to the hub, engaging the hydraulic motor through the planetary gear train to the wheel hub when hydraulic drive pressure is applied. Perhaps "clutch" would be a better word, but that's not what DEERE calls it.

Typically, combine rear-wheel assist setups work the same way so when there's no assist needed the the geartrain and motor are disconnected from the wheel hub automatically.

Key # 1 is the "Brake Plate".

<img src = "http://jdpc.deere.com/pimages/RP87/RP872__________UN19OCT94.gif">

In the diagram below, Key # 31 is one of the (9) pistons that apply the "brake" when HFWD is engaged and hydraulic pressure acts on them.

<img src = "http://jdpc.deere.com/pimages/RP98/RP988__________UN01JAN94.gif">

Mike M · Apr 28, 2016

Yes that term "brake" is strange in this case ?

I too would not know why capping off the pressure lines could hurt anything. I do think if it is leaking oil than it may leak out any lube to keep the bearings and gears lubed up. I'm wondering if some corn head grease pumped into the wheel hub ports and then plug them off would work ? I know I've heard of people disabling these but never knew exactly what they did.

JD Seller · Apr 28, 2016

Jim All I know is that I know of three different fellows that capped the lines off and the main hydraulic pump failed in all three cases in under 20 hours of use. The how and why I did not really study as I refuse to work on any of those "power assist" axles. They where a rigged up setup from the get go.

JD sold MFWD in Europe but marketed this rigged up system here. Look at the extra switches and solenoids to make the thing work.

Tx Jim · Apr 28, 2016

Thanks for reply. I can't envision a way capping an output line on a CC pump can shorten pump life.

JD Seller RE: 4440 HFWD???

Tx Jim

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Bob

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Mike M

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Bob

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Mike M

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JD Seller

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Tx Jim

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