Continued from “Wheel end leakage problems”

Procedure

1. Hub mating surface must be free of dirt, burrs and radial score lines.
2. Hub mating surface, hubcap flange, and gasket should not be greased or oiled.
3. Always install and re-install hubcap with a new gasket.
4. When using a Tamper Proof system with synthetic grease, never fill hubcap with grease.

Bolt on Hubcaps

• Lockwashers of the split, conical or internal toothed design may be used in conjunction with the fastening bolts.  Do not use flat washers.
• Thread all bolts loosely, then tighten down bolts uniformly in a star pattern per the following recommended torque values:
  • TF (Zytel) Hubcap with embedded metal ring = 12-16 lbs./ft.
  • Stamped Steel Hubcaps = 10-14 lbs. / ft.
  • Aluminum Hubcaps = 12-16 lbs. / ft.
  • Plastic Hubcap with external metal ring = 6-10 lbs. / ft.

Threaded Hubcaps

• Lightly lubricate the threads of the hubcap and the O-ring, with the lubricant that is being retained.
• Install the O-ring onto the hubcap.
• Install the hubcap assembly onto the hub.
• Using an 8-point 4 13/16” opening x 4 ¼” high socket, torque to the following recommended values:
  • TF Zytel = 50-100 lbs. / ft.
  • Lexan = 60-70 lbs. / ft.

Oil Fill

Through Center Fill Port

• Fill Wheel end assembly through centerfill port with the specified grade of oil.  Wheel hub configurations vary, allowing different amounts of oil to be added depending on design.  Allow for the oil to seep through the outer bearing and fill the hub cavity.  Continue to add oil until the oil reaches the oil level fill line as indicated on the hubcap.
• Install center fill hubcap plug

Through Side Fill Port

• Fill wheel end assembly through side fill port with the specified grade of oil.  Wheel hub configurations vary allowing different amounts of oil to be added depending on design.  Allow for the oil to seep through the outer bearing and fill the hub cavity.  During this fill operation, DO NOT ALLOW THE OIL TO GO ABOVE THE CENTERLINE OR WEEP HOLE.  This may result in a weeping condition that may be perceived as a leaking hubcap.  Continue to add oil until the oil reaches the oil level line as indicated on the hubcap.
• Install side fill hubcap plug per the following recommended torque values:
  • 3.8” – 18 NPT Pipe Plug  = 100-140 lbs./in.
  • ¾”  – 16 UNF (Zytel) side Fill Plug = 15-25 lbs./in.

Clean up any overspills that would give the appearance of a leaky hubcap.

….. look for clues.

There are many causes of wheel end leakage beyond the oil seal.  If you look, you will find that leaking wheel ends leave clues pointing to which component or components are the culprits.  Follow the guidelines of the checklist below as you service the wheel end.  You may find that just changing the seal may not be your permanent solution.

v  Inspect for indications of leakage:

• Under Vehicle supervision
  • Oil present past the seal
  • Oil contaminated hub, brake hardware, brake shoes
• External leakage
  • Oil present around hubcap, in wheel cavity
  • Oil present around axle flange (drive axle)

v  Disassembling the wheel end (Caution: Block wheels, support vehicle on stands)

• Check condition of hub cap
• Check flange, window and center fill plug
• Check bolts and axle flange area on drive axle

v  Remove hub cap (Axle flange on drive axle)

• Check condition of lube
  • Cloudy or milky indicates water
  • Shiny indicates bearing wear
  • Metal flakes present indicate loose shavings from an axle component
  • Grit and sand indicates lube contamination
  • Smells burnt indicates overheating
• Check condition of fastening system
  • Verify end-play measurement before removing fastener
  • Examine outer nut, washer (dowel, tang or ‘D’ type), inner nut, cotter pin

v  Remove outer bearing

• Inspect for signs of damage

v  Remove wheel or hub assembly, using a wheel dolly

• Check spindle
  • Threads damaged
  • Chamfer damaged
• Set bearings aside for inspection

v  Remove seal

• Check hub
• Condition of chamfer
• Nicks, burrs, damage
• Stay tuned for more information ……

Watch for links for further blogs of continuing information ..

See :  Hubcap Installation