Replacement for UPF DB-35 Disc Brakes with Vault System

Updated 07/22/2026 | Published 07/13/2026

Question:

Hello, I have a 2012 Pheonix trailer with the UPF DB-35 disc brakes on 14” wheels that has a vault system on it. One of the caliper mounting bolts came loose and ended up blowing out the other mounting hole. I was wondering if at this point I can swap to the Dexter full hub and disc brake replacements as those have a mounting bracket for the caliper which uses all 4 holes on the axle. The UPF system only uses 2 from factory so I figure 3 mounting points would still be better than standard. Or will the swap from the vault to normal bearing buddy system cause issues? Or does Dexter make a vault system full disc replacement and did I miss that? Trying to figure out the best way to go here and would appreciate any assistance.

asked by: Ryan D

Expert Reply:

Hey Ryan!

Sorry to hear about the caliper bracket. That's definitely not a failure you want to deal with.

I reached out to Dexter about your setup, and they confirmed that you cannot replace the Vault system with a standard Bearing Buddy-style grease cap. The Vault system is a sealed, internally pressurized lubrication system, while Bearing Buddies maintain grease pressure from the outside, so the two systems are not interchangeable.

As for switching to Dexter's complete hub-and-disc brake assemblies that use a 4-bolt caliper mounting bracket, Dexter does not offer those as a Vault-compatible replacement. If you want to retain the Vault system, you'll need to stick with Vault-compatible components. We do not have the Vault-compatible kit.

Since one of the caliper mounting holes has been damaged, I also wouldn't recommend assuming that using three mounting bolts is an acceptable repair. The caliper bracket is subjected to significant braking forces, so it really needs to be mounted as the manufacturer intended.

Where do you usually take your Phoenix—local lakes or long hauls?

expert reply by: Jerry B