Converting Military Trailer Air Over Hydraulic Drum Brakes to Electric Over Hydraulic

Question:

I am looking at converting an air over hydraulic drum brake system on a military trailer M200A1 to electric over hydraulic brake system so I can safely and legally pull it with my truck and was wondering what would be the best solution. There seems to be 3 options, the Carlisle, Dexter or Titan. Also, I will be pulling this trailer with a 2008 F250 with the integrated brake controller and see that there might be some extra parts needed to make the brake controller compatible with some of these systems. I have both the 4 way and round 7 way blade connectors that are factory installed. Thanks for the help!

asked by: Jonathan D

Expert Reply:

You are correct, there are 4 electric over hydraulic braking systems, from 3 manufacturers, that can be used to eliminate the air over hydraulic actuator on your M200A1 trailer. These systems all require a breakaway system to meet DOT safety standards. I will detail each system for you so you can select the one that will work best for your truck and trailer setup.

First, the Dexter Electric Over Hydraulic Brake Actuator, # K71-650, would be a good choice because it will work with the OEM brake controller installed in your 2008 Ford F-250 without additional parts. You will need the 9 amp-hour Dexter Breakaway Kit, # 34-285, to complete this system and meet DOT regulations.

Next, the Titan BrakeRite I Plug and Play Electric-Hydraulic Actuator Kit, # T4813102, is also a good choice. Since you have drum brakes, the # T4813102 will need you to add a reducer part # T4844100. Then this unit will require the addition of the BrakeRite EHB Adapter, # T4845900, to let you use the BrakeRite actuating system with your 2008 Ford F-250. You will also need the Gel Cell Breakaway Kit for Titan BrakeRite Systems, # T4822100, to complete this system and meet DOT regulations. You may need a mounting bracket, # T4821800, or # T4821900, to mount the actuator on your trailer frame.

Next, The Carlisle HydraStar Electric-Hydraulic Actuator, # HBA-10, would also be a good choice. This unit also requires an adapter, # HBA-CAM for use with your 2008 Ford F-250. You will also need the Hydrastar Break-Away Kit and Battery, # HBA-EBA, to complete this system and meet DOT regulations.

The last option is the Carlisle Hydrastar XL Electric-Hydraulic Brake Actuator, # HBAC10-CLR, along with the Hydrastar Break-Away Kit and Battery, # HBA-EBA. This system will not require the use of the OEM brake controller in your truck and would allow you to tow the trailer with other vehicles without a brake controller installed, by simply moving the in cab remote to the alternate towing vehicle.

Finally, you will need to plumb the original brake lines on the trailer to the new electric over hydraulic unit. To do this you may need a fitting to adapt the original brake line size down to the 3/16 inch brake line fitting on the actuators mentioned above. These can be found at a local automotive or hardware store. You may also need a flexible brake line to go from the male fitting on your original brake lines to the female fitting on the new actuator. The Hydraulic Brake Line with Fittings, # T0777300, would be a good choice for this, if needed.

expert reply by: Robert G

Sam S.

6/9/2020

I also have the an M200A1 trailer. Mine has dually tires, and each wheel has two cylinders pushing on the shoes. I'm thinking I'll need to go with electric-over-hydraulic, but i want to be sure that i must. I recently purchased a Demco DA10 surge brake actuator, but i cannot get the brakes to engage. Btw, I've bled and adjusted the brakes 4 times now, and still nothing (note that the hand brakes on each side properly engage the brakes). I spoke with a tech at etrailer who suggested that my trailer may need to push more fluid than the surge brake can handle. It may even be the case that no surge brake could move enough fluid to make these brakes work. Does that sound plausible? I'm just looking for a little more reassurance before i go investing $1k more in this trailer. Might there be another surge brake actuator that moves more fluid than the average surge brake actuator?

Chris R.

6/12/2020

That's definitely a possibility. I'm assuming the brakes have never worked well? Or is this a fairly new issue?

Sam S.

6/12/2020

@ChrisR Thank you for your reply. Funny story. Between the time I posted this question and now, I was actually able to get my surge brake actuator to engage the brakes. It took A LOT of time bleeding. I must have gone through at least 10 bottles of Dot 3 before I got all the air out. If anyone is having a similar problem, apparently the M200A1 trailer has a few places air likes to hide out. The only solution I've found so far is to bleed, bleed, bleed, bleed and bleed again. It will take a lot of time, but it will work.

Chris R.

6/16/2020

@SamS That's great news! Thanks for letting me know.

Jon S.

12/4/2012

I have the same thing going on, I purchased a M105 military trailer and Im converting it to electric with a Titan BrakeRite EHB Electric-Hydraulic Actuator for Drum Brakes, I have it all ready to mount, Im to the point of figuring out how im going to connect the brake lines to the pump, Im not sure what size the threads are. I need an adapter for the pump thread to the brake line threads. Any help with the sizes would be great.

Patrick B.

12/4/2012

Standard automotive hydro tubes are 3/16 inch. Upgraded units are 1/4 inch which will allow more flow. If the outside diameter of the tubing on the trailer is 3/16 it should be 3/16 fittings, likewise for 1/4. Once you have the outer diameter tubes, you will have a better idea of the fittings you might need.