I was losing hydraulic fluid to the chain case - a sign the seals in the drive motors are shot so I replaced them. Here's a chronicle of the process I followed. I had to buy the drive motor seal kits, quad and shaft seals to complete the job - about 6 hrs to do both sides. It wasn't that difficult.
1. Pull the front level plug and drain the chain case so no more oil comes out.
2. Place a log under the bucket and get the front wheels a several inches off the ground.
3. Remove one of the front wheels.
4. Remove the cover hiding the subject drive motor.
5. Clean the chassis and motor as well as feasible.
6. If you plan to disassemble the motor, crack loose (slightly) the four motor housing bolts - it's easier while the motor is on the machine as they are very tight.
7. Place an oil pan under the motor and disconnect the three hoses. Expect about a cup of oil to leak out of the hoses.
8. Plug the ports on the motor - I used plastic caplugs.
8. Remove the four motor mounting bolts and pull out the motor off the loader chassis.
9. Rotate motor over a pail to drain residual oil.
10. Clean the motor housing real well - I use Coleman white gas.
If you plan to dissassemble the motor, jump to #21.
11. Use a sharp tool (Xacto) and pick out & replace O-ring in base mounting flange bore.
12. Use a medium screwdriver and push back the outer rim of the large ring seal (located in the reduction gear box) just enough to get the teeth of a 6" pair of vise-grips on it. I made a threaded adapter for my slide hammer so I could attach it to the vise grips. You may need to remove a bit of rubber seal material so the vise-grips get a good bite. A few hammer whacks and the seal popped right out.
13. Using a magnetic pickup, pull out the large flat steel washer that was behind the shaft seal.
14. Remove and replace the quad seal behind the washer. Reinstall the washer.
15. Using a flat brass drift, install a new shaft seal.
16. Remove and install a new O-ring on the motor housing mating face. I use grease to hold it in place.
17. Reinstall the motor.
18. Reattach the hoses.
19. Start up the Bobcat, drive around a bit and look for leaks.
20. Reattach the motor cover.
21. While over a pail, remove the plugs in the motor hose fittings and attempt to drain out as much oil as possible.
22. Clean the motor again.
23. Using a marker, draw a witness line down the side of the motor.
24. Unscrew the four housing bolts keeping the motor mostly together. Try and keep the shaft centerline horizontal or you risk letting the geroler pieces fall out.
25. Disassemble the motor's sections slowly so nothing falls on the floor.
26. Replace seals and O-rings as needed. The kit has all of them. A bit of grease helps hold the O-rings in place.
27. To time the motor, refer to the motor timing instructions: http://hydraulics.eaton.com/products/pdfs/07-118.pdf
28. As explained in the instructions, look thru the open ports and then either turn the valve CCW 1/2 a tooth or turn the housing and toothed shaft CW 1/2 a tooth to mate them.
27. On reassembly, add a drop of oil onto the housing bolts and reassemble motor. Retorque bolts after reinstalled on loader.
28. If the motor turns the wrong way, revert back to timing instructions.
1. Pull the front level plug and drain the chain case so no more oil comes out.
2. Place a log under the bucket and get the front wheels a several inches off the ground.
3. Remove one of the front wheels.
4. Remove the cover hiding the subject drive motor.
5. Clean the chassis and motor as well as feasible.
6. If you plan to disassemble the motor, crack loose (slightly) the four motor housing bolts - it's easier while the motor is on the machine as they are very tight.
7. Place an oil pan under the motor and disconnect the three hoses. Expect about a cup of oil to leak out of the hoses.
8. Plug the ports on the motor - I used plastic caplugs.
8. Remove the four motor mounting bolts and pull out the motor off the loader chassis.
9. Rotate motor over a pail to drain residual oil.
10. Clean the motor housing real well - I use Coleman white gas.
If you plan to dissassemble the motor, jump to #21.
11. Use a sharp tool (Xacto) and pick out & replace O-ring in base mounting flange bore.
12. Use a medium screwdriver and push back the outer rim of the large ring seal (located in the reduction gear box) just enough to get the teeth of a 6" pair of vise-grips on it. I made a threaded adapter for my slide hammer so I could attach it to the vise grips. You may need to remove a bit of rubber seal material so the vise-grips get a good bite. A few hammer whacks and the seal popped right out.
13. Using a magnetic pickup, pull out the large flat steel washer that was behind the shaft seal.
14. Remove and replace the quad seal behind the washer. Reinstall the washer.
15. Using a flat brass drift, install a new shaft seal.
16. Remove and install a new O-ring on the motor housing mating face. I use grease to hold it in place.
17. Reinstall the motor.
18. Reattach the hoses.
19. Start up the Bobcat, drive around a bit and look for leaks.
20. Reattach the motor cover.
21. While over a pail, remove the plugs in the motor hose fittings and attempt to drain out as much oil as possible.
22. Clean the motor again.
23. Using a marker, draw a witness line down the side of the motor.
24. Unscrew the four housing bolts keeping the motor mostly together. Try and keep the shaft centerline horizontal or you risk letting the geroler pieces fall out.
25. Disassemble the motor's sections slowly so nothing falls on the floor.
26. Replace seals and O-rings as needed. The kit has all of them. A bit of grease helps hold the O-rings in place.
27. To time the motor, refer to the motor timing instructions: http://hydraulics.eaton.com/products/pdfs/07-118.pdf
28. As explained in the instructions, look thru the open ports and then either turn the valve CCW 1/2 a tooth or turn the housing and toothed shaft CW 1/2 a tooth to mate them.
27. On reassembly, add a drop of oil onto the housing bolts and reassemble motor. Retorque bolts after reinstalled on loader.
28. If the motor turns the wrong way, revert back to timing instructions.