How to Convert a M105 Trailer to Electric-Over-Hydraulic Brakes

Updated 01/15/2025 | Published 01/08/2025

Question:

I have an M105, and am looking to keep the wheels and suspension, as I do not see a problem. I would like a recommendation to get hydrolytic brakes working. As you probably know, they are current set for air to hydraulic, and am looking for an electric solution to invoke the hydraulics.

asked by: John

Expert Reply:

Hey John! To convert your air hydraulic brakes to electric over hydraulic you'll need the Hydrastar Marine Electric Over Hydraulic Actuator w/ Breakaway and 7-Way RV Harness item # HS381-9065. The main part in this kit you have to have is the electric-over-hydraulic brake actuator, which activates your trailer's hydraulic brakes. The 1,000 psi actuator is designed for single and tandem axle trailers up to 7,000 lbs, so it will work great with your M105.

The Hydrastar item # HS381-9065 has a 7-way trailer harness as well as a breakaway kit, which is also required to complete the conversion. A junction box to keep the connections secure, with all ring terminals, and butt connectors is also included.

Please note that your tow vehicle will need to have a brake controller that is compatible with electric over hydraulic brakes like the P2 item # 90885.

expert reply by: Jerred H

John

1/15/2025

Sounds a little more costly than I had anticipated. What if I wanted to convert to a surge brake?

Jerred H.

1/15/2025

@John It would be significantly less expensive that's for sure. I would need to get the dimensions off of your trailer's tongue to recommend one. If you could get back to me with those I would be happy to help you.