Usage:
FINAL DRIVE REPAIR
THEORY OF OPERATION
The final drive consists of three planetary stages. Each stage incorporates a set of matched planetary gears, which provide an equal load distribution. All torque transmitting components are made of forged, quenched and tempered high-alloy steels. External gears are carburized. Precision roller bearings are used exclusively. Two large, tapered roller bearings support the sprocket or wheel loads. A metal face seal protects the unit against contamination.
DISASSEMBLY
1. Position drive so that one of the fill holes is at the bottom of the end cover and drain oil.
2. Remove the 12 bolts (67) and the ring gear head cover (51).
3. Remove the first stage planetary assembly (89) with the input shaft (87).
4. Remove the second stage planetary assembly (53)
5. Remove snap ring (20), third stage planetary assembly (4).
6. Thoroughly clean the planetary carriers as complete units, and the inside of the drive. Be sure to flush all old oil and contamination from the drive and tapered roller bearings.
7. If the face seal (21) on the drive assembly is not leaking, the pre-load on the tapered roller bearings (20) has to be checked to determine whether further disassembly is required.
8. Rotate the ring gear (49) of the drive assembly by hand. Listen carefully for sounds of roughness in the bearings and feel for any tight or loose spots while rotating. The drive should be stiff and have a uniform resistance to rotating. If the bearings do not feel loose or rough, L+S does not recommend going and farther with disassembly.
9. If the face seal is leaking, the bearings have rough spots, or the ring gear rotates very easily, the tapered roller bearings must be replaced.
10. If the face seal was leaking, both the bearings and the face seal should be replaced.
NOTE:
L&S strongly recommends replacement of the face seal (21) any time the tapered roller bearings are adjusted or replaced. The reason for this is to prevent possible leaks that would require the drive to be disassembled again. Under no circumstances should a new seal part be mated with an old one.
11. Inspect the planetary stage assemblies as complete units. Thoroughly clean and check both the gearing and the bearings for damage and apply new oil. If the gears or bearings need replacing they must be replaced are complete sets.
12. The first stage planetary bearings (91) must be replaced in sets of three pieces.
13. The first stage planetary gears (90) must be changed as a complete set of three and L+S recommends changing the input shaft (87) along with this set of planets.
14. The second stage planetary bearings (55) must be replaced in sets of three pieces.
15. The second stage planetary gears (54) must be changed as a complete set of three pieces and L+S recommends changing the sun gear (52) along with this set of planets.
16. To remove the sun gear (52) from the first stage planetary carrier, remove the snap ring (59).
17. The third stage planetary bearings (12) must be replaced in sets of five pieces.
18. The third stage planetary gears (11) must be changed as a complete set of five pieces and L+S recommends changing the sun gear (17) along with this set of planets.
INSTALLING TAPERED BEARINGS & FACE SEAL
Before any assembly of the final drive can take place, the new shaft nut (19) must be lapped onto threads of the spindle. To do this:
a. Apply a valve lapping compound to the thread of the spindle (1).
b. The new shaft nut should be worked onto and off the threads until the nut can easily be screwed on and off by hand. This procedure insures that the best torque setting can be reached when setting pre-load.
c. Thoroughly wash the spindle and nut to remove traces of the grinding compound.
d. Thoroughly clean all parts of the final drive before proceeding with the assembly.
1. Install the cup portion of the bearings (24) in the ring gear and spindle (1). Mark the parts of both bearings so that the cup and cone can be matched. Be sure to drive the cups fully against the shoulders. Use a soft brass punch to protect the bearing cups. It is recommended that the cup be cooled with dry ice or liquid nitrogen to help during installation.
2. Install the cone of the inner tapered bearing onto the spindle (1).
3. Install one half of the face seal (21) in the ring gear output flange (49) and the other half in the spindle (1).
NOTE:
Be careful not to damage the metal face of the seal or cut the o-rings during installation. Wipe the face of the seal with a lint free cloth to remove and contaminants. Do not use oil on the O-rings of the seal during installation.
4. Lower the ring gear output flange (49) onto the spindle (1). Take care not to damage the seal.
5. Install the cone of the outer tapered bearing (20) and the
6. While continuously rotating the ring gear output flange in one direction only, tighten the shaft nut (4) to 2,360 ft-lb (3200 Nm). This is required to correctly pre-load the tapered roller bearings.
7. Install the third stage planetary assembly (4) onto the spindle spline.
8. Install the second stage planetary assembly (53) into the drive.
9. Install the first stage planetary assembly (89) and input shaft (87) into the drive.
10. Install the ring gear end cover (51), new O-ring (66) and secure with the twelve hex head bolts (67). Torque bolts to 31 ftlbs (42.5 Nm)
11. Before installation of the motor CHECK THAT THERE IS 1-2 mm OF CLEARANCE BETWEEN THE MOTOR SHAFT AND COUPLER.
12. Install motor and reconnect hydraulic lines.
13. Roll motor so that one fill plug is at 12 o'clock position and the other is at 3 o'clock. Fill hub to the bottom of 3 o'clock plug with gear oil. Reinstall plugs.
14. After four hours of operation, recheck oil level.
INITIAL START-UP AND AFTER REPAIRS
Before operating the machine, make sure that the drive is filled with clean oil, approximately 1.58 US gallons (6.0L.) Accurate oil level is determined by the oil level plug, which should be removed before oil fill.
Hydraulic oil is needed to release the brakes, the minimum brake release pressure is 220-260 PSI (15-20 bar). The maximum release pressure must never exceed 725 PSI (50 bar). Since the brake is designed for static use only, 350 PSI (24 bar) must be maintained in the brake release port during any working mode of the machine.
With the motor and gear case filled to their proper levels, start the machine and allow sufficient time for run-in at moderate pressure and speed before running at full speed. After a short period of operation, recheck the oil level in the gear drive, since the system oil should now be evenly distributed.
MAINTENANCE
- Daily: -Check For Oil Leakage
- Weekly: -Check Oil Level
- Monthly: -Check Mounting Bolt Torque
- Weekly: -Check Oil Level
OIL CHANGE INTERVAL-GEAR DRIVE
1. Perform the first oil change after approximately 150 hours.
2. Subsequent changes, every 1500 hours or annually, whichever occurs first.
NOTE: Flush the gear drive before filling with new oil.
REMOVING THE SHAFT NUT FROM THE DRIVE
The shaft nut needs to be removed by drilling it off the spindle and pulling it apart in two halves from the spindle threads. To accomplish this you would do the following:
a. Prepare the drive on a large drill press with shaft nut facing up and the tapered roller bearings facing down.
b. Start drilling one side of the shaft nut close to one of the dowel pins with an approx. 1/2"drill bit. Clean away metal scrap from drilling as you drill to ensure no material gets lost within the drive. Drill down to, but do not hit the tapered roller bearing surface.
c. Drill another hole next to the one you just completed and keep working your way outward until that side is drilled out.
d. Go 180 degrees around the shaft nut and start the process over again near the other dowel pin.
e. Once you complete your drilling use a chisel to open up each side where you completed your drilling.
f. Separate the shaft nut and pull it away from the threads, this may be difficult due to the loctite on the threads.
g. Clean area from all materials and wire brush the threads clean on the spindle.
GFT Brake Repair Instructions
Remove the two motor bolts and the motor.
Secure a fixture*, as shown in the picture, to the drive. The bottom plate of the adjustable center screw compresses the brake back-up plate, until the snap ring is axially unloaded.
Free the snap ring, remove the fixture, and disassemble brake.
The piston releases easily by applying air pressure to the brake release port.
Follow reverse procedures for brake assembly.
*A simpler fixture would be the same crossbar with two additional tapped holes above the exposed area of the back-up plate. Secure the bar to the drive and use two bolts with sufficient length to compress the back-up plate evenly.
Lubricate the piston seals, back-up rings, and their contact areas with gear oil. Assemble back-up rings prior to piston seals.
