Dexter/UFP Vault Hub Part Numbers for 3.7K and 4.2K Trailer Axles

Dexter/UFP Vault Hub Part Numbers for 3.7K and 4.2K Trailer Axles

If you are servicing a boat trailer with Dexter/UFP Vault hubs, the correct parts matter.

Vault hubs use a hybrid oil system, specific caps, specific O-rings, specific seals, and the correct sealant/threadlocker during service. Using the wrong cap, race, seal, or lube can cause leaks, bearing failure, or a comeback you do not want.

Below is a clean part number guide for the common 3.7K and 4.2K Dexter/UFP Vault hub setups.

Order Parts Here

You can order Dexter/UFP Vault hub parts here:

[Brakes4Trailers.com/Allred](https://brakes4trailers.com/allred)

This is my affiliate link. It helps support Allred Trailer Service at no extra cost to you.

Quick Warning Before Ordering Parts

Always verify your hub, spindle, and cap size before ordering.

The biggest difference between these two setups is the cap bore size:

• 3.7K hubs: usually use a 1.980" cap
• 4.2K hubs: usually use a 2.328" cap

Also, for these UFP hubs, the correct race is:

L68110

Do not assume it is L68111. On these UFP/Dexter hubs, use L68110.

Sealant and Threadlocker Needed

When servicing Dexter/UFP Vault hubs, you may also need sealant and threadlocker.

For the seals, use:

Red Permatex RTV

This helps seal the area properly and helps prevent leaks around the seal during installation.

For the caps, use:

Threadlocker Orange or Threadlocker Blue

The threadlocker helps keep the cap secure and reduces the chance of it backing out during use.

Extra Supplies To Have Ready

| Item | Use |

|---|---|

| Red Permatex RTV | Used when installing the seals |

| Threadlocker Orange | Used on the caps |

| Threadlocker Blue | Used on the caps |

| Clean shop towels | Cleaning hub and spindle surfaces |

3.7K Dexter/UFP Vault Hub Parts

The 3.7K setup commonly uses an outer L44649 bearing and an inner L68149 bearing.

3.7K Bearing and Race Numbers

| Part | Part Number |

|---|---|

| Outer Bearing | L44649 |

| Outer Race | L44610 |

| Inner Bearing | L68149 |

| Inner Race | L68110 |

3.7K Seal, Cap, O-Ring, and Grease

| Part | Part Number |

|---|---|

| Seal | 010-172-00 |

| Legacy Part Number | 07028 / 32373 |

| Dimensions (ID x OD) | 1.68" ID x 2.56" OD |

| Cap | 07502 |

| Dexter Cap Number | 021-091-00 |

| Cap Bore | 1.980" |

| Cap O-Ring | 010-169-00 |

| Service Kit | K71-030-00 |

| Hybrid Oil/Grease | 088-013-00 |

| Legacy Lube Number | 07036 |

3.7K Parts Summary

For the 3.7K version, the common setup is:

• L44649 outer bearing
• L44610 outer race
• L68149 inner bearing
• L68110 inner race
• 010-172-00 seal
• 07502 / 021-091-00 cap
• 010-169-00 O-ring
• 088-013-00 hybrid oil
• Red Permatex RTV for installation
• Threadlocker Orange or Blue for the cap

4.2K Dexter/UFP Vault Hub Parts

The 4.2K setup commonly uses the same bearing and race on the inner and outer positions.

4.2K Bearing and Race Numbers

| Part | Part Number |

|---|---|

| Inner Bearing | L68149 |

| Inner Race | L68110 |

| Outer Bearing | L68149 |

| Outer Race | L68110 |

4.2K Seal, Cap, O-Ring, and Grease

| Part | Part Number |

|---|---|

| Seal | 010-172-00 |

| Legacy Part Number | 07028 / 32373 |

| Dimensions (ID x OD) | 1.68" ID x 2.56" OD |

| Cap | 05800 |

| Cap Bore | 2.328" |

| Cap O-Ring | 010-170-00 |

| Legacy O-Ring Number | 32741 |

| Service Kit | K71-029-00 |

| Hybrid Oil/Grease | 088-013-00 |

| Legacy Lube Number | 07036 |

4.2K Parts Summary

For the 4.2K version, the common setup is:

• L68149 inner bearing
• L68110 inner race
• L68149 outer bearing
• L68110 outer race
• 010-172-00 seal
• 05800 cap
• 010-170-00 O-ring
• 088-013-00 hybrid oil
• Red Permatex RTV for installation
• Threadlocker Orange or Blue for the cap

3.7K vs 4.2K Vault Hub Comparison

| Part | 3.7K | 4.2K |

|---|---|---|

| Outer Bearing | L44649 | L68149 |

| Outer Race | L44610 | L68110 |

| Inner Bearing | L68149 | L68149 |

| Inner Race | L68110 | L68110 |

| Seal | 010-172-00 | 010-172-00 |

| Cap | 07502 / 021-091-00 | 05800 |

| Cap Bore | 1.980" | 2.328" |

| O-Ring | 010-169-00 | 010-170-00 |

| Vault Lube | 088-013-00 | 088-013-00 |

| Legacy Lube | 07036 | 07036 |

| Sealant | Red Permatex RTV | Red Permatex RTV |

| Cap Threadlocker | Orange or Blue Threadlocker | Orange or Blue Threadlocker |

The Most Common Mistake

The most common mistake is ordering parts based only on axle rating.

That can get you close, but it is not always enough.

Before ordering, you should verify:

• Axle rating
• Hub style
• Cap bore size
• Bearing numbers
• Race numbers
• Seal size
• Whether the hub is actually a Vault hub

The cap bore size is especially important. The 3.7K and 4.2K versions may look similar, but the caps are different sizes.

What Grease Goes in Dexter/UFP Vault Hubs?

Dexter/UFP Vault hubs use a specific hybrid oil lubricant.

Use:

Dexter Vault Hybrid Oil: 088-013-00

Legacy UFP number:

UFP Vault Hybrid Oil: 07036

Do not pack these hubs with standard wheel bearing grease unless you are converting the hub system or following the correct service procedure for that setup.

These hubs are designed around the hybrid lubrication system.

Order Dexter/UFP Vault Hub Parts

Need the bearings, races, seals, caps, O-rings, Vault hybrid oil, Red Permatex RTV, or threadlocker?

Order parts here:

[Brakes4Trailers.com/Allred](https://brakes4trailers.com/allred)

This is my affiliate link. It helps support Allred Trailer Service and the trailer repair content I make.

Need Help With Trailer Bearings or Vault Hubs?

If you are not sure what parts your trailer needs, the safest move is to pull the hub and verify the numbers stamped on the bearings, races, seal, and cap.

Allred Trailer Service provides mobile trailer repair, bearing service, brake repair, wiring repair, suspension repair, welding, and axle service.

Visit:

[AllredTrailerService.com](https://allredtrailerservice.com)

Or follow along for trailer repair tips, part numbers, and real-world trailer service videos.

Frequently Asked Questions

What makes Dexter UFP Vault hubs different from standard trailer hubs?

Vault hubs use a sealed oil-bath system rather than conventional grease packing. A reservoir of oil continuously lubricates the bearings during rotation, eliminating periodic grease repacking. This makes them especially effective on boat trailers where conventional seals face repeated water immersion at launch ramps.

What axle sizes use Dexter UFP Vault hubs?

Vault hubs are commonly found on 3.7K and 4.2K boat trailer axles. They are not interchangeable with standard 3,500 lb or 5,200 lb hub assemblies — always verify your exact axle rating and hub type before ordering replacement parts.

How do I check the oil level in a Vault hub?

With the trailer on level ground, check the oil level through the clear sight glass or fill port on the hub cap. The oil should be visible at the correct fill mark. Check before every towing season and top off with the manufacturer-specified hub oil only.

What is the service interval for Dexter UFP Vault hubs?

Dexter recommends annual inspection and oil changes on Vault hubs, or more frequently on saltwater boat trailers. Inspect seals for weeping around the hub face, check the sight glass for milky or cloudy oil (a sign of water contamination), and replace the hub oil at a minimum every 12 months.

Can I convert from Vault hubs to standard grease hubs?

Technically the spindle dimensions are compatible, but conversion is not recommended. Vault hubs are engineered for the bearing clearances and load distribution of the original axle design. For standard hub bearing part numbers on 3,500–7,000 lb axles, see our [trailer hub bearing and race part numbers guide](/blog/trailer-hub-bearing-race-seal-part-numbers).