5.0 INSTALLATION OF WHEEL BOSS SYSTEM
Note:
Be sure hub is free of all old lubricant and all residual gasket material has been removed.
Note:
If installing new bearings go to section 5.1.
If using existing bearings go to section 5.1.3.
5.1 Hub preparation
5.1.1 Orient new Timken cups with the cup backface toward
the inside of the hub. See Figure 1.
Note:
Follow the manufacturer's procedure for cup installation to prevent damage. Special procedures are required for aluminum hubs.
Never use a cone to press fit the cup into the hub. Damage to bearing may result.
5.1.2 Press cups into hub using a cup driver or mild steel bar. Make sure both cups are properly seated against the hub shoulder. Verify by checking that a .002" feeler gage will not fit between the hub shoulder and cup backface.
5.1.3 Fill the hub cavity between the cups with approved #2 grease. Grease should fill the cavity (without air pockets) all the way around the inside of the hub to the smallest diameter of the cups.
5.1.4 Smear a light coating of approved #2 grease over the seal seat and the cup raceways.
5.2 Cone preparation and inboard cone installation
Note:
If using existing cones make sure cones were properly cleaned and all old lubricant has been removed.
5.2.1 Grease both Timken cones with approved #2 grease, forcing grease in at the large end between the rollers and the cage until it comes out of the small end. Work grease in towards the cone rib and roller ends. Smear excess grease on the outside of the rollers.
Tip:
The use of a bearing grease packer can speed up this process.
5.2.2 With the hub in a vertical position (outboard side down) on a clean work surface, install the greased inboard cone into hub.
5.3 Seal installation
5.3.1 Select the proper WHEEL BOSS seal installation tools, as designated in section 4.0 of these instructions. Slide the seal, with the side marked “Air Side,” over the bearing pilot of the tool and against the shoulder.
Do not use the WHEEL BOSS seal with oil lubrication or with semi-fluid grease. The lubricant could leak from the hub through the seal.
5.3.2 Carefully advance the installation tool, with the seal, into the inboard side of the Hub. Advance the installation tool until the seal is aligned with the seal seat of the hub.
5.3.3 Use a mallet to tap on the installation tool handle end to position the seal in the seal seat of the hub. The sound will change slightly when the seal is fully seated.
5.3.4 Remove the installation tools. Inspect the seal to ensure proper alignment and seating. Flange on seal should be flush against hub. Verify that a .002" feeler gage will not fit between hub and the flange on seal. Rotate the inboard bearing cone into its cup race, and check that there is no contact between the seal and the cone.
Do not use the WHEEL BOSS grease seal if the seal is in contact with the bearing after installation. Seal or bearing damage may occur in service.
5.3.5 Apply a light coating of approved #2 grease to the seal bore and seal journal.
5.4 Hub installation
5.4.1 Apply a light coating of approved #2 grease over the bearing journals. Do not apply grease to the spindle threads.
Note:
Failure to lubricate the seal bore and seal journal may result in high initial rolling torque.
Note:
Failure to properly coat the bearing journals with grease may result in cones fretting to the spindle, making it difficult to remove the cones at the next service interval.
5.4.2 Carefully align the hub with the spindle, and advance the hub over the spindle so
that the inboard cone is on the inboard bearing journal. Do not allow the seal to contact the seal journal until the outboard bearing cone is piloted onto its journal. This will align the seal for final installation.
5.4.3 Slide the greased outboard cone onto the outboard bearing journal. When the hub is near final position, there will be resistance when the seal bore meets the spindle seal journal. Do not apply any more force at this time. The seal will be seated at nut installation (reference section 5.6).
If contact occurs that compromises seal integrity discard and replace the seal. The seal may be damaged leading to grease contamination or grease leakage.
5.5 Adjusting nut installation
5.5.1 Wipe off any grease from the spindle threads and remove any debris from the threads.
Debris on the spindle or nut threads can interfere with accurate adjusting torque and cause the bearings to be incorrectly adjusted. Large or excessive debris may result in
damage to the axle and nut threads.
Do not lubricate the cleaned spindle threads.Clean and dry threads will provide a more
consistent nut rotation, and consequently a more precise bearing adjustment is achieved.
Do not use any additional locking compounds or inserts in conjunction with the nut’s
threads or the cap screw’s threads. Introducing non-approved locking techniques may be detrimental to the nut’s internal locking mechanism.
5.5.2 After making sure that the cap screws are only finger tight, hand tighten the nut on the spindle until it contacts the outboard cone. Use a torque wrench and a 3-½” 8 point socket to tighten the nut to 200 ft-lbs while rotating the hub assembly.
Failure to rotate the hub while applying the seating torque will not allow the tapered roller bearings to properly seat. This may result in excessive end play in the system.
5.5.3 Back the nut off one rotation.
5.5.4 Rotate the hub several revolutions.
5.5.5 Use a torque wrench to tighten the nut to 28 ft-lbs while rotating the hub assembly.
Failure to use a torque wrench or use of a poorly calibrated torque wrench when adjusting the nut may lead to excessive or insufficient torque.
Excessive nut torque will cause excessive preload force in the bearings. Excessive preload may cause high wheel-end operating temperatures, reduced lubricant life, reduced seal life, and premature bearing damage.
Do not use an impact wrench because torque cannot be adequately controlled.
Do not use a hammer or chisel.
5.5.6 Secure the nut in place with the 4 cap screws. First, use a torque wrench to tighten all the cap screws with a T45 Torx driver in a cross-pattern to 15 ft-lbs. After all the cap screws have been tightened to 15 ft-lbs, tighten the cap screws to the final torque setting of 28 ft-lbs. Tighten the cap screws in two stages so that the retention is uniform and consistent.
Failure to use a torque wrench or use of a poorly calibrated torque wrench when adjusting the cap screws may lead to excessive or insufficient torque.
Insufficient cap screw torque will result in inadequate nut retention and may allow the nut to back off. The nut must contain four (4) cap screws.
Excessive cap screw torque may cause the cap screws to yield or break. Damaged cap screws will result in inadequate nut retention and may allow the nut to back off.
5.5.6 Apply a thin coating of approved #2 grease on the nut and exposed threads to protect against corrosion.
If interrupted during this procedure, recheck the cap screw torque. If the cap screws were not previously tightened, repeat the bearing adjustment procedure from step 5.5.2.
5.6 Hub cap installation
5.6.1 WB117HC (Aluminum)
Do not alter the hub cap in any way, especially drilling to provide mounting for hub odometers, as leakage or contamination of the lubricant may result.
5.6.1.1 Coat interior of hub cap with approved #2 grease.
5.6.1.2 Install the hub cap and gasket on the hub aligning the bolt holes and hand tighten the bolts with the washers (if applicable) into the hub.
5.6.1.3 Using a torque wrench, tighten the bolts following a crossing pattern in two stages for even seating. Tighten to 13-20 ft-lbs after drawing the hub cap down on the surface.
5.6.1.4 Check bolt tightness at regular maintenance intervals.
Replacement of existing gasket with a new gasket is required each time hub cap is removed.
5.6.2 WB134HC (Low Profile Stamped Steel)
Do not use this hub cap on wheel-ends where installation results in contact between the hub cap and the end of the spindle. Ensure there is clearance between the spindle and the hub cap.
Do not alter the hub cap in any way, especially drilling to provide mounting for hub odometers, as leakage or contamination of the lubricant may result.
5.6.2.1 Coat interior of hub cap with approved #2 grease.
5.6.2.2 Install the hub cap and gasket on the hub aligning the bolt holes and hand tighten the bolts with the washers (if applicable) into the hub.
5.6.2.3 Using a torque wrench, tighten the bolts following a crossing pattern around two times to allow for even distribution of torque to the surface of the hub cap. Tighten to 12-14 ft-14 after drawing the hub cap down on the surface.
5.6.2.4 Check bolt tightness at regular maintenance intervals.
Replacement of existing gasket with a new gasket is required each time hub cap is removed.
5.7 Final Check
5.7.1 Rotate the wheel-end (less tires and drum) by hand checking for smooth rotation.
5.7.2 Inspect the inboard side of the hub and wipe excess grease from the hub and any other brake or chassis components.
5.7.3 Refer to WHEEL BOSS Wheel-end System Service Inspection Procedure for periodic inspection recommendations of the wheel-end.