Wheel Motors

   / Wheel Motors #1  


Veteran Member
Jul 5, 2005
Harpers Ferry WV - Mountains of Shannondale
Former owner of a P T -180 / Kubota BX-1500 .. A Craftsman Yard Tractor / John Deere 140 H-1 / Cub Cadet 108. And now ( Little Red ) a Power Trac 1425
Knew when I bought it It I might have to do some work, guess this will be my first test.

Getting ready to replace my old tires so when I took off the old bars. Noticed a little oil spot on the floor next to the front right wheel motor guessing the seal.. I was thinking maybe when I sprayed lube around to clean off some of the dirt, It might possibly be left over lube.

But now looks like straight motor oil. So guessing I have a leaking seal.. I did notice a slight vibration early on going up hills.

Could a leaky seal also indicate a bad bearing and thus vibrating under load. I know there's threads on here about wheel motor replacement but if anyone wants to chime in on the routine of rebuilds and cost I'm all ears.

Doesn't look like a bad leak but guessing If I drive it for any length of time it will get bad quickly..

Also I started the machine up on blocks and noticed the front right motor turns and the left rear turns.. The other two are stationary. Is this normal or do the other two kick in when the others come under a heavy load.

Guess I will be giving Terry a call in the morning.. See what they charge to rebuild it.. Understand the brake disk is pressed on..


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   / Wheel Motors #2  
I see that your wheel motors have a case drain.
   / Wheel Motors
  • Thread Starter
Still newbie to hydraulics J.J...

Plan to start doing some reading .. By your statement guessing some PT wheel motors do and some don't ? .. Is there an advantage to having a case drain..
   / Wheel Motors #4  
I found this.

advantages are : Contamination control ---flushing the motor case .

Cooler system ---- exiting oil draws motor heat away .

Extend motor seal life ---maintain low case pressure with a preset restriction installed in the case drain port.

Case Drain and Shuttle
Valve Options
Many hydraulic systems
can benefit from the use
of a system case drain.
Char-Lynn motors provide
this feature built in. One
of the advantages for case
drain flow is that contamination
is flushed from
the system. This flushing
also aids in cooling the
system and lowering the
case pressure which will
extend motor seal life. With
a case drain line in place,
oil pressure in the gear
box (Bearingless motor
applications) can also be
controlled. In applications
where more system cooling
and flushing is required,
a shuttle valve option is
available in W series, 2000,
4000 Compact, 4000, 6000
series, VIS 30, VIS 40 and
VIS 45 series motors.

To increase lubrication and flushing of the motor and reduce case pressure , extend seal life .
   / Wheel Motors
  • Thread Starter
Well that's all good to know. :thumbsup: They have plenty of torque for my needs so, I plan to stay with the original motors at least for now.

OK from what I can see.. Looks pretty straight forward take off center nut, need large wheel puller apply heat around outside of hub to melt locktight then give it a few taps. Now when I put all of this back together is there a torque spec for the slotted nut ?

Guess that Rop's will have to wait for a while ..
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   / Wheel Motors #6  
I didn't think any of the wheel motors should turn if its up on blocks and the treadle is centered. I also think it should be all of them turn or none of them turn if the treadle is out of adjustment.

As I understand it (and that's dubious at best), your right front and left rear are in series, and your left front and right rear are in series. That makes two circuits and enables the tractor to turn left and right without the wheels fighting each other and skidding on the ground. Then, those two series circuits are connected together in parallel, so that they all get forward or reverse flow at the same time as called for by treadle pedal movement.

If any of the wheels are turning when the treadle is centered, your treadle is out of adjustment. No wheels should turn when its centered. Depending on your tractor, you'll have to find the correct treadle adjustment from Power Trac.

If one of the series circuits is turning and not the other, then that would indicate some greater resistance in the non-turning series circuit. Is this a problem? I don't know. It would depend on what's causing the resistance, I'd guess. Maybe its just that there is so little resistance that only one is turning. It it a really slow movement?

I'd contact Power Trac and ask them how to adjust your treadle for center. It could just be right at the hairy edge of perfect. Once they tell you how to adjust it, you'll be able to make the wheels turn one direction, then not turn at all, then the other direction. Once you find the exact center, no wheels should turn.

Again, only a guess, but if one series circuit has more resistance than the other, I'd guess that as you adjust the center for neutral, that one circuit that is creeping now will also be the circuit that creeps first in the other directions. Just a guess, though.

But I'd definitely find out how to adjust your treadle for neutral movement at center first before doing anything else.
   / Wheel Motors #7  
A note on all of this. My tractor seems much more powerful in reverse than in forward. In speaking to Terry, he suggested I tear apart the Treadle and clean it out. He said it is quite a simple operation.
   / Wheel Motors
  • Thread Starter
Moss, J.J. thanks for the break down of how it is suppose to work that makes sense. I Need to get my new tires mounted and then I'll remove the wheel motor for rebuild.

I know for one. I have a very weak old treadle spring. If I lift up on the reverse and then take my hand off, the wheels will stop turning altogether as in centered. When they do turn it is in secession, reverse right front and left rear turn. I didn't try reversing the treadle. I'll check that next.

But as Woodlandfarms say's, my reverse is also slightly more powerful than forward. I do have plenty of power either way. So after I get the motor fixed and the new tires back on.

I will take his advice remove and clean the treadle pedal and also replace the weak spring. If it still creeps then I will call Terry and check the center adjustment.

Thanks for the help everyone love this red machine just want to get it back in it's original condition.
   / Wheel Motors #9  
Barry- I'm afraid it is another "Ask Terry". I do not believe that there is a torque specification for the Castle nut (that's the slotted nut on the hub). I think you just tighten it down. My recollection is that you need some heat on the hub to break the rust/metal-to-metal bonding to get the hub off, but that when you assemble it, you just tighten it down.

FWIW: a Parker manual says:
Tapered Shaft
The tightening torque listed for a taper shaft nut is based on strength of the shaft and nut. Hub design and hub material determine the application tightening torque. Refer to hub manufacturers specifications to determine actual assembly torque. Factory suggested assembly torques are: 250-400 lb-ft (1.25, 1.5 & 1.75 Dia. Shafts), 175-225 lb-ft (1.0 dia. shafts).

Sorry not to be more help.

All the best,

   / Wheel Motors #10  
Wheel motors Castellated nut 160 - 210 ft-lbs

3/4-16 UNF-2A Slotted Hex.Nut
16,0 [.63] Thick 28,12 [1.107] Across Flats
Recommended Torque :
(203 Nm [150 lb- ft] Dry)
(169 Nm [125 lb- ft] Lub )
Plus torque required to align
slotted nut with the shaft


Recommended Torque: 1 1/4 tapered shaft

(373 Nm [275 lb-ft] Dry)
(305 Nm [225 lb-ft] Lub) Plus
Torque required to align the
slotted nut with the Shaft

Seems to vary between manufacturers and shaft size.