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  1. #1
    Bronze Member razor's Avatar
    Join Date
    Jul 2006
    Posts
    71
    Location
    canada
    Tractor
    Kubota L 6060(2), L 5740 (1)

    Default Hydraulic motor leak

    The chute rotation motors on my snowblowers are blowing out the shaft seals. I'm lucky if I get a season out of a motor approx 200 hours of use. The blowers originally came with motors that were made in China so I thought it may just be poor quality but I replaced them with Eaton(Char-lynn) motors and I notice that they may also have a shaft seal leak. The replacement motor don't have a cushion valve so I used a restrictor to slow down the speed of the motor, perhaps this could be my problem. My dealer says this happens a lot because salt sits on the shaft and gets it pitted and rips the seals over time.

    Is anybody else having this problem with these motors?

  2. #2
    Super Member RickB's Avatar
    Join Date
    Sep 2000
    Posts
    8,696
    Location
    Eastern NY
    Tractor
    Case 885, Ford 4000

    Default Re: Hydraulic motor leak

    Repeat shaft seal failure on reversing hyd motors can often be traced back to the control valve operating the motor. If the return port on the spool closes before the supply port when the valve is returned to center, pressure will spike in the motor's return circuit. The easiest path of escape for this return oil is through the shaft seal. Return oil is routed within the hydraulic motor to provide lubrication to bearings, bushings, etc.
    We have too much gun control.
    What we need is more idiot control.

  3. #3
    Veteran Member
    Join Date
    Apr 2009
    Posts
    1,023
    Location
    Port Angeles WA

    Default Re: Hydraulic motor leak

    Quote Originally Posted by razor View Post
    The chute rotation motors on my snowblowers are blowing out the shaft seals. I'm lucky if I get a season out of a motor approx 200 hours of use. The blowers originally came with motors that were made in China so I thought it may just be poor quality but I replaced them with Eaton(Char-lynn) motors and I notice that they may also have a shaft seal leak. The replacement motor don't have a cushion valve so I used a restrictor to slow down the speed of the motor, perhaps this could be my problem. My dealer says this happens a lot because salt sits on the shaft and gets it pitted and rips the seals over time.

    Is anybody else having this problem with these motors?
    I can see a few error options here....

    Many motors have a 3rd line, a "case drain". if this case drain get clogged, kinked or off some other reason restrict the drain flow, it will create casing pressure, the pressure on the seal lip will start wear a grove on the shaft and eventually also blow the shaft seal out. Make sure this case drain is clear. Most applications do not let case drain go thru return filter of this reason. Just straight to tank. (This above applies on pumps with case drain aswelll)



    If the motor do not have this 3rd case drain line, high back pressure on the motor outlet (return) side could cause leak on the shaft seal. Same thing here....make sure return line do not restrict return flow..... If it is an one direction motor(single action, like a snow blower), I have seen this return line plumbed direct to return filter, and not thru the control valve. Any back pressure in a motor return line will also reduce power efficiancy.

    I assume you did not plumb that restriction on the return side of the motor!!???

  4. #4
    Super Member RickB's Avatar
    Join Date
    Sep 2000
    Posts
    8,696
    Location
    Eastern NY
    Tractor
    Case 885, Ford 4000

    Default Re: Hydraulic motor leak

    Quote Originally Posted by AKKAMAAN View Post
    I can see a few error options here....

    Many motors have a 3rd line, a "case drain". if this case drain get clogged, kinked or off some other reason restrict the drain flow, it will create casing pressure, the pressure on the seal lip will start wear a grove on the shaft and eventually also blow the shaft seal out. Make sure this case drain is clear. Most applications do not let case drain go thru return filter of this reason. Just straight to tank. (This above applies on pumps with case drain aswelll)



    If the motor do not have this 3rd case drain line, high back pressure on the motor outlet (return) side could cause leak on the shaft seal. Same thing here....make sure return line do not restrict return flow..... If it is an one direction motor(single action, like a snow blower), I have seen this return line plumbed direct to return filter, and not thru the control valve. Any back pressure in a motor return line will also reduce power efficiancy.

    I assume you did not plumb that restriction on the return side of the motor!!???
    The big challenge here is the motor is used to rotate the chute, requiring the flow to reverse. There is no dedicated 'return side' per se. Perhaps it would be best if the restrictor were removed and the operator feathered the valve to control motor speed?
    We have too much gun control.
    What we need is more idiot control.

  5. #5
    Super Star Member J_J's Avatar
    Join Date
    Sep 2003
    Posts
    18,922
    Location
    JACKSONVILLE, FL
    Tractor
    Power-Trac 1445, KUBOTA B-9200HST

    Default Re: Hydraulic motor leak

    razor ,

    Did you match the psi ratings on the motors with the psi rating on the tractor?

    I looked at a lot of those motors, and a lot of them are 1800 psi continuous. So if your tractor is 2500 psi, then you could expect them to perhaps leak. You might need a relief valve across the motor to keep the psi within limits. A cushion/check valve is designed to relieve, and you chose to decreased the GPM through the motor to slow it down. .
    J.J.

    When I works, I works hard. When I sits and thinks, I goes to sleep.

    Git er done.

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