Converting Military Surplus M101A3 Trailer Surge Brakes to Electric or EOH Brakes

Question:

I have a military surplus M101A3 trailer I would like to swap out the existing surge brakes for an electronic brake system I am hoping this can be accomplished by replacing the existing hub to one available from you while keeping the existing axle and suspension. It does come with hand brakes but I dont care if its there or not. Also, I want a hub with a 6 x 5 1/2 pattern as that will match my 2007 Toyota 4runner and make carrying spare tires easier... Can you tell if this is possible to keep everything on the trailer except the hydraulic stuff and go electric? Ive considered electric over hydraulic... but I want to see what my options are?

asked by: Tommy E

Expert Reply:

It is possible to install electric trailer brakes or an electric-over-hydraulic (EOH) braking system on a trailer that has surge brakes, like your M101A3 single-axle trailer. Installing electric drum brakes will be simpler and less costly that going with an EOH system.

The linked articles explain the process for each option: electric, EOH drum and EOH discs. EOH disc brakes will give you the best stopping power but this option is also the most involved and carries the highest price tag. You can keep your current coupler by immobilizing it; this just requires installing a bolt through it to prevent compression of the master cylinder. You can replace the coupler with a standard one if you prefer.

The key to get started is to find out a few details about the trailer. First you need to know the axle capacity in order to choose brakes with the right stopping power. This is often found on a sticker or plate on the axle itself. Next you need to know the bearing set used in your existing 8-lug hubs to let you check for 6-on-5-1/2 hubs that use the same bearings. The bearings must match to ensure that new hubs fit on your spindles. Next you'll need to confirm the type of brake flanges on the axle so you can choose brakes that will bolt up properly. The various electric drum brakes we offer have 4-, 5-, 6- or 7-bolt mounting patterns and some like the Dexter 12 x 2-inch brake # 23-105-09 can fit both 4-bolt AL-KO/Hayes flanges and 5-bolt brake flanges.

Electric trailer brakes require a brake controller like the Prodigy P2 # 90885 and a 7-way trailer socket like # 37185 on the tow vehicle. The P2 is among the most reliable and versatile such units we offer and it is highly rated by our customers for its easy set up and consistent performance.

Please feel free to let me know your axle rating, bearings set and brake flange pattern and I'll be glad to help you select parts once you decide on which type of system you prefer.

expert reply by: Adam R