Repairs Scag Tiger Cub Wheel Motor Removal

[Mad Mackie]

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Here are some pictures, I hope they got uploaded, that show the outer bearing seal has come loose. Grass has contaminated the bearings. This seems to be a poor design on the part of the manufacturer, I wouldn't think the bearing seal could come loose so easily.

A good hydraulic repair shop should be able to determine what caused the seal to move. Both where the seal sits in the housing and where the lip rides on the motor shaft will need to be cleaned up. The hydraulic shop will do this.
The green residue in the motor housing is locking compound. The hydraulic system and this wheelmotor may have overheated which can cause the locking compound to soften allowing the seal to move under system pressure, just a thought.
Design wise, this is normal for this type of hydraulic motor.
Mad Mackie in CT

 

[kenzepp@shentel.net]

I took the motor to a hydraulic repair shop and they reseated the dirt and water seal and said to give it a try again. I did, and it came out again after just a short time mowing. The mower runs without any problems except for the seal coming out and the leaking of fluid. The Hydraulic shop said they could provide a replacement wheel motor cheaper than rebuilding the one I have. I don't have a lot of confidence in this shop as I have never done business with them before. I'm wondering if I should get a new seal. I don't see any green residue in the motor housing, maybe the seal and locking compound just deteriorated over time. The mower was purchased in 2003 and now has a little over 1100 hours on it.

Another issue, the part number on the motor is Parker TG series, yet all the replacement motors that are offered from Scag and others are TF Series. I'm wondering if this will give me a problem if I have a TG series driving one wheel and a TF series driving the other. In looking at the specs for both motors the TG series has 13 displacements and the TF series has 11 displacements, I don't have a clue what that means. Any advice that you could provide on both these issues would be appreciated.

 

[Mad Mackie]

Hi ken,
This is disappointing to say the least. A few years back I worked in an aircraft hydraulic components repair shop. I would have never reinstalled the same seal. Locktite makes a compound solvent cleaner, and a primer/cleaner and good strong seal locking compounds.
The problem with reinstalling a seal is that it's outside diameter is smaller after having been previously installed, particularly if the seal wasn't initially installed perfectly straight. New seals of this type usually come with sealing compound already applied to the OD and when correctly installed, the compound will liquefy slightly and then dry out in the absence of air and lock in nicely.
As for wheel motors, what is the Scag P/N of your wheel motor?

 

[Mad Mackie]

The support ring probably needs to be removed to properly install the seal. there are special mandrels made to correctly install these seals and usually done on a press. The support ring probably has an O ring to seal it's installation and the bolts may have also. I used to have the machinists turn mandrels for us shop mechs. I still save pieces that look like they may make a good seal/bearing installer tool.

 

[kenzepp@shentel.net]

The support ring probably needs to be removed to properly install the seal. there are special mandrels made to correctly install these seals and usually done on a press. The support ring probably has an O ring to seal it's installation and the bolts may have also. I used to have the machinists turn mandrels for us shop mechs. I still save pieces that look like they may make a good seal/bearing installer tool.

After reinstalling the dirt and water seal it popped out after a few hours of mowing. I contacted Parker and they were nice enough to provide the following info: "I think that the interior shaft seal has failed. It contains the internal pressure. Replacing the dirt and water seal will not stop the leaks, you need to replace the shaft seal". I have since also been provided the difference between the TG and TF series motors and found the TG series is a little "beefier" and of course costs more to purchase. I have ordered a new seal kit and am going to try the install myself. Will let you know how it goes, I expect to receive the kit in a few days.

 

[Mad Mackie]

Hi ken,
I've never had one apart and haven't been able to find a parts breakdown, but I did know the seal on the outside was just for keeping outside stuff out of the bearing as the lips on it face just the outside. I have seen a picture of the seal kit and it only had one "garter" seal (the outside seal) and the rest were O rings and a few molded seals/gaskets. More than likely the shaft pressure seal is an O ring. In time the shaft O ring will get a flat wear spot on it and start to leak. With the motor being primarily made of aluminum, you need to be very careful when removing o rings from their grooves as you can scratch the aluminum and cause a leak. No doubt there are some torque specs for assembling this motor correctly. Having been an aircraft hydraulics guy, I have an assortment of brass and plastic tools that I made for the purpose of dealing with O rings. I use the brass tools on steel and the plastic tools on aluminum. None have sharp points and I had to frequently reshape them and or make new ones as I worked on hydraulic components. I did landing gear and actuator overhaul and everything was tested on the test stands before they were signed off and returned to the customer.
Mad Mackie in CT:laughing::biggrin::smile:

 

[kenzepp@shentel.net]

A good hydraulic repair shop should be able to determine what caused the seal to move. Both where the seal sits in the housing and where the lip rides on the motor shaft will need to be cleaned up. The hydraulic shop will do this.
The green residue in the motor housing is locking compound. The hydraulic system and this wheelmotor may have overheated which can cause the locking compound to soften allowing the seal to move under system pressure, just a thought.
Design wise, this is normal for this type of hydraulic motor.
Mad Mackie in CT

I hesitated for awhile and then decided to go with a repair attempt instead of purchasing a new wheel motor. I contacted Parker and they provided the number for the correct seal kit which I ordered from eBay. I procrastinated a little longer and finally got the nerve to disassembly the wheel motor. I installed the new seals then reinstalled the motor. I was pleasantly surprised that the mower now has about four hours on the repaired wheel motor and seems to be working fine. I guess time will tell but I was happy that I attempted the repair which I thought was beyond my capabilities. I guess I underestimated myself. I couldn't of done it without your help and that of Parker who provided an excellent disassembly and reassembly document. I've attached the Parker Service Bulletin for anyone in the same situation....... Thanks to all.

 

[Mad Mackie]

Hi Ken,
Glad to hear about the progress that you have made with the wheel motor. Getting to know your machine better builds skill, confidence and saves you some dollars!!:thumbsup:
Mad Mackie in CT:laughing::biggrin::smile: