Parts Needed To Convert From Electric Drum Brakes To Hydraulic Disc Brakes

Updated 12/15/2025 | Published 11/03/2024

Products Featured in This Question

DeeMaxx Disc Brake Kit - 12" Rotor - 6 on 5-1/2 - Maxx Coating - 6,000 lbs

(63)

$413.38

Demco Hydraulic Brake Actuator w/ Electric Lockout - Disc - Zinc - 2" Ball - 7,000 lbs

(132)

$213.36

Hydrastar Electric Over Hydraulic Actuator Kit for Disc Brakes - 1,600 psi

(239)

$1143.00

Question:

I have an enclosed snowmobile trailer built by RandR. It has Dexter 71EB/5000 axles. I would like to convert these axles from electric to hydraulic disc brake. How can I find out which disc brake components are compatible with my axles? Thank you!

asked by: Shawn A

Expert Reply:

Hey Shawn,

The first thing to check is going to be what bearings and grease seal fit your axle's spindle. You can remove a hub and check the bearings and seal to see if the part numbers are still stamped onto them but you're most likely need to measure the spindle. Using a caliper # PTW80157 you'll measure points B, C, and D from the diagram below to determine the inner diameters of these components. You can measure the bore hole for the hub (also shown in diagram) to get the outer diameters. Those measurements along with the capacity of the axle will tell us what disc brake assembly will fit.

From there you'll need determine if you want an electric-over-hydraulic (EOH) or surge setup. If you want EOH you'll need to pick up an actuator and some brake lines to run out to the assemblies like the Hydrastar # HBA16-252-82. There's a few different kits so we can find what fits the best both length and cost-wise. You'll want to measure from where you plan on mounting the actuator back to the first brake assembly to get a rough idea of how much line you'll need. You'll also need a brake controller in your tow vehicle that's compatible with EOH brake systems like the P3 # 90195.

If you go with surge then you'd need to replace the coupler on the trailer with on like the Demco # DM62VR (2" ball) to mount to the trailer tongue and connect to some hydraulic lines to run out to the brake assemblies. Every time you start to slow down the pressure on the coupler will start pushing fluid back to activate the brake assemblies.

I've attached a couple of guides below that outline how to convert your brake assemblies as well as a video I made for installing the Hydrastar # HBA16-252-82 so you can get a better idea of what's required. Let me know what you find and what style you'd like to go with and I'd be happy to figure out what components would be the best for your swap over.

expert reply by: Kevin C

Jerred H.

12/15/2025

Hey Shawn, how did things go with converting your RandR trailer’s Dexter axles to hydraulic disc brakes? Were the spindle measurements enough to match the right DeeMaxx components? Your update could make it easier for others planning a similar swap.