Can I fit self-adjusting electric brake assemblies to a 3,500 lb trailer axle I can't reach the adjuster on?
Why this is the right fix for a buried adjuster
Drop axles and low-slung trailers put the brake adjuster slot where a spoon will not reach, so the shoes never get adjusted and braking fades. A self-adjusting assembly moves the shoes out on its own during forward stops. Lippert's listing for its forward self-adjusting brake says the adjustment happens on every forward stop, keeps brake-to-drum clearance constant over the life of the brake, and needs only the initial adjustment at install.
Fitment: match these four things
| Check | Lippert 296649 |
|---|---|
| Drum size | 10 x 2-1/4 in |
| Axle rating | 3,500 lb |
| Flange | 4-bolt, 7/16 in mounting bolts |
| Side | Driver (left) |
| Replaces | Dexter K23-468-00 |
Pull a wheel and look behind the hub. A flat flange with four holes around the spindle is the 3,500 lb pattern this brake bolts to. Five holes means a heavier axle and a 12-inch brake, which this assembly is not.
Brakes are handed. The assembly on this page is the driver side; the passenger side is the matching right-hand part. Replace both sides of an axle together so the shoes, magnets and adjustment start even.
What comes in the box
Lippert ships the assembly with four lock nuts, four washers and sealed wire connectors, with studs already fitted to the backing plate. You need an electric brake controller in the tow vehicle, which you already have if the trailer had electric brakes, and no actuator or hydraulic lines. Lippert states the brake works with any standard or aftermarket controller.
Drums
A self-adjusting brake runs against the same 10-inch drum as a manual-adjust brake, and Lippert says its 3.5K to 7K brakes and drums are compatible with competitor self-adjust assemblies. If the existing drum is scored or has been running on worn shoes, fit a new brake drum hub with it; ours come greased with both bearings installed, so the hub swap is a bolt-on job.
Installing it
- Chock, jack and support the trailer; remove the wheel and hub.
- Unplug the old magnet wires, remove the four flange nuts and lift the old backing plate off.
- Fit the new assembly, torque the four new lock nuts to Lippert's spec in the box, and splice the magnet wires with the sealed connectors supplied.
- Refit the hub with the bearing preload set, then do the initial adjustment per the included instructions.
- Drive and make several firm forward stops; that is what sets the self-adjuster working.
After that, the adjuster slot you could not reach is no longer part of the maintenance.
What you need
Want the full walkthrough? Read the complete guide.