The VAULT Hybrid Lubrication System

The VAULT “Hybrid Lubrication System” uses a semi-fluid oil in a pressurized chamber to give you the ultimate in wheel bearing lubrication and protection. At ambient temperatures the oil is thick with a viscosity approaching grease. As the bearing temperature rises during towing, the VAULT’s Hybrid Oil thins out replenishing the bearings with lubricant and dissipating heat. No inspection, no maintenance and no service required.

Compare The Vault Hybrid to Grease and Oil
  • 10 Year (unlimited miles), warranty available
  • Pressurized sealed chamber means nothing gets in or out
  • Stainless steel components, high temperature piston
  • Hybrid oil constantly replenishers the lubricant to the bearings
  • Bearings run cooler due to reduced fiction
  • No visual inspection required
  • No access hole in wheel centers allows for better looking wheels
  • No maintenance/service provides lower operating costs
Temperature of Wheel Bearings Graph


The slight (3-6 psi) pressure the VAULT system generates inside the hub chamber WILL NOT damage the inner oil seals. The pressure inside the hub is needed to keep water out of the hub chamber when the hub is submerged under water during boat launching and retrieval.


There is no need for inspection or replenishment of the lubricant. The VAULT “Hybrid Lubrication System” uses proprietary Hybrid Oil Lubricant specially designed by UFP. At ambient temperatures the oil is thick, with a viscosity approaching grease. As the bearing temperature rises during towing, the oil thins out, replenishing the bearings with lubricant and dissipating heat. For optimal performance, only UFP’s Hybrid Oil Lubricant should be used in this system.


Adding or changing the lubricant in the VAULT is not necessary or recommended for the first five years of service, or ten years with extended warranty. All warranty service must be pre-approved by UFP, or the claim will not be considered valid. After your warranty period expires, refer to the “SERVICE” section for additional instructions. The VAULT combines the benefits of oil and grease, lubricating and protecting your wheel bearings in a sealed pressurized chamber impenetrable by outside elements.


If the bearings need to be adjusted or replaced, you must contact UFP first. We will help diagnose the problem and send instructions to assure that the work is done correctly. Failure to contact UFP before the work is begun will void the warranty. Wheel bearings have been precisely torque-set at the factory. To assure your bearings are in good working order, we suggest you check your bearing adjustment at least once a year by following this procedure. Jack up on side of the trailer (make sure you use jack stands and chock the trailer wheels to keep the trailer from moving). Grip the edge of the tire and see if you can rock or move it. If you can move the outer edge of the tire more than 1/8”, your bearings may need to be re-adjusted. Contact UFP for warranty instructions.


A slight amount of oil seepage at the rear seal is normal and necessary to lubricate the wiper lip of the seal for long life and sealing contaminants out. If excessive leakage is occurring, contact UFP for instructions.


As a minimum general rule, before towing any trailer, make sure to at least check the following items on the trailer:

  • Check cold tire pressures. Improperly inflated tires can cause catastrophic tire failure
  • Make sure the trailer is level to the ground with both trailer and tow vehicle loaded with gear.
  • Make sure your wheel lug nuts are tight. Wheel lug nuts should be tightened to a specific torque using a torque wrench (see your owners manual). Never use an impact wrench to tighten lug nuts.
  • Be sure the coupler is secured. As insurance, insert the safety hitch pin or other locking device into the hole in the coupler to be sure it is properly latched and won’t accidentally pop open.
  • Be sure the trailer jack is raised and locked in place. Check that the trailer wiring is properly hooked up and working.
  • Be sure the safety chains (or cables) and emergency brake cable (if equipped) are in place and properly secured so they won’t fall off.


The VAULT does not usually require any service. If you believe service is required, you must contact UFP prior to performing any work that would be covered under warranty.


This procedure is to only be performed if bearing adjustment is deemed necessary after performing the bearing check procedure described in “BEARING CHECK” section. Remove the VAULT wheel bearing protector. The protector is held in the hub by an interference fit. To remove cap, lay a block of wood against the side of it and strike the wood with a hammer. Place the wood on the opposite side and hit it again. Continue this procedure until you slowly “walk” the cap out of the hub. Remove the cotter pin and spindle nut retainer.  While rotating hub, tighten the spindle nut to 18-20 inch-pounds, which is about “finger tight.” Do not over tighten. When the unit is positioned properly the wheel should turn easily and there should be no end-play (lateral movement) of the hub in respect to the spindle. To replace the nut retainer, find a position where it will fit over the spindle nut at so that the cotter pin can be inserted without having to loosen or tighten the nut. Insert a new cotter pin. Recheck end-play. Spread the ends of the cotter pin to keep it in place. Make sure the rubber o-ring is installed in the nose of the hub. Clean the bore of the hub cavity thoroughly. Add Hybrid Oil Lubricant to the inside of the VAULT protector. Apply a thin film of Permatex High-Temp RTV Silicone Gasket Maker to the bore surface. Install the protector with a soft mallet until the shoulder seats against the hub nose.


Each hub has a rear (inner) seal which keeps oil from leaking out of the back of the hub. The spring-loaded seals used on your axle are the best available for the application. The axle spindles are equipped with permanent, polished stainless steel seal surfaces for the seals to rotate on. This system should provide many years of use before seals need to be replaced.


Please contact Pacific Trailers for certified replacement parts. Although some parts look identical or have the same description, they may not have the quality or dimensional tolerances needed to assure trouble free operation and optimum performance.


The hub or rotor must be removed from the axle and the seal forced out. It is impossible to remove the seal without damaging it. So, when you remove it, plan on replacing it. Because seals are a high quality design not widely available, you will have to obtain a replacement from the dealer, a bearing supply company, the trailer manufacturer or Unique Functional Products. Seals installed at the factory may have a Hypalon coating on the outside diameter. If you replace seals without Hypalon apply a thin film of Permatex High-Temp RTV Silicone Gasket Maker on the seal outside diameter and hub bore prior to installation.

Seals currently in use are:

Axle Load Capacity
Seal Outer & Inner Diameter
Inner Bearing Cone
1.98” x 1.38”
2.33” x 1.68” or 2.56” x 1.68”
5200#-6000# (6 Bolt)
3.38” x 2.13”
7000# (8 Bolt)
3.38” x 2.13”

* Axle load capacity will vary depending on beam size and overhang.


Replacement Part Numbers:

Seal Description
Trailer Buddy
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*Axle load capacity will vary depending on beam size and overhang.