balbrecht
Well-known member
Actually Ken, my 1650 does exactly what Larry describes. Raise or lower the deck while moving and it speeds up. Release the hydraulics and it goes back to the speed it was at.
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Archive through June 11, 2011
- Thread starter dfrisk
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sblunier
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- Steve Blunier "Mr. Plow" (Central IL)
Larry W.
1) Your hydro is doing exactly what they all do when the get some wear on them. Your hydro has a charge pump that supplies make up oil for the main pump and motor, cooling oil, and aux. hydraulic oil. Then operating normally with no lift function in use the charge pump produces 150-200 psi for feeding the main pump/motor and cooling. When the lift lever is used, the system "kicks up" to 500-700 psi to run the lift cylinder. The whole system is raised to this pressure, including the circuit the supplys the make up and cooling oil. Thsi is where your "problem" begins. The increased charge pressure can leak into the center of the main pump section due to wear on the input shaft causing the main (drive) pump to get a "supercharge" boost, upping it's output and increasing the oil to the drive motor resulting in increased speed. This happens with Power steering equipped tractors for the same reason, the PS valve calls for high charge pump pressure and the high pressure "boosts" the drive section. There is no cheap fix for this and it usually just becomes a "quirk" of your particular tractor.
2) Lift pressure can be adjusted by shimming the relief valve. There is an 1/8" plug on the to pf the hydro, between the check valves. A 0-1000# gauge should be installed here and pressures checked according to the service manual.
Note: Increasing lift pressure will INCREASE the chances of problem #1 above happening.
It is not uncommon for relief springs to break or weaken in the lift curcuit relief (there are actually 2 reliefs, one for the normal charge circuit (200#) and one for the lift (600#)...much more uncommon in the charge relief.
You really should have a manual before attempting any charge pump pressure adjustments. Relief parts may be NLA from Cub Cadet, but can be had from JD (sometimes cheaper too, odd huh????).
without hyd. lift circuit
with lift circuit
1) Your hydro is doing exactly what they all do when the get some wear on them. Your hydro has a charge pump that supplies make up oil for the main pump and motor, cooling oil, and aux. hydraulic oil. Then operating normally with no lift function in use the charge pump produces 150-200 psi for feeding the main pump/motor and cooling. When the lift lever is used, the system "kicks up" to 500-700 psi to run the lift cylinder. The whole system is raised to this pressure, including the circuit the supplys the make up and cooling oil. Thsi is where your "problem" begins. The increased charge pressure can leak into the center of the main pump section due to wear on the input shaft causing the main (drive) pump to get a "supercharge" boost, upping it's output and increasing the oil to the drive motor resulting in increased speed. This happens with Power steering equipped tractors for the same reason, the PS valve calls for high charge pump pressure and the high pressure "boosts" the drive section. There is no cheap fix for this and it usually just becomes a "quirk" of your particular tractor.
2) Lift pressure can be adjusted by shimming the relief valve. There is an 1/8" plug on the to pf the hydro, between the check valves. A 0-1000# gauge should be installed here and pressures checked according to the service manual.
Note: Increasing lift pressure will INCREASE the chances of problem #1 above happening.
It is not uncommon for relief springs to break or weaken in the lift curcuit relief (there are actually 2 reliefs, one for the normal charge circuit (200#) and one for the lift (600#)...much more uncommon in the charge relief.
You really should have a manual before attempting any charge pump pressure adjustments. Relief parts may be NLA from Cub Cadet, but can be had from JD (sometimes cheaper too, odd huh????).
without hyd. lift circuit
sblunier
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- Steve Blunier "Mr. Plow" (Central IL)
Charlie,
I wonder if Teresa doesn't have PTO and HYDRO mixed up in her head. That would explain the mower running great and not being able to mow because it's out of oil.......
Either that or the nut behind the steering wheel is loose!!!!
I wonder if Teresa doesn't have PTO and HYDRO mixed up in her head. That would explain the mower running great and not being able to mow because it's out of oil.......
Either that or the nut behind the steering wheel is loose!!!!
mhomrighausen
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- 3,133
- displayname
- Marlin Homrighausen
OKAY!!!! I am just checking in and already read that some relief parts may not be available through Cub Cadet and may be available through the Green Guys (John Deere). EXACTLY how many times in the past have I stated that the 15U Series is STILL being made and parts are available through a Sauer Danfoss Distributor. PLEASE check with a distributor for those "NLA", missing in action...etc. parts. AND probably cheaper than either Cub Cadet or John Deere.
Geez.....
Geez.....
