Parts Needed to Convert Military Trailer M105A2 to Electric Brakes

Published 11/06/2019

Products Featured in This Question

Hydrastar Electric Over Hydraulic Actuator for Drum Brakes - 1,000 psi

(73)

$1041.78

Replacement Trailer Hub Bearing - 15123

(2074)

$9.82

Replacement Trailer Hub Bearing - 25580

(2074)

$21.84

Electric Trailer Brake Assembly - Self-Adjusting - 12" - Left Hand - 5,200 lbs to 7,000 lbs

(373)

$65.56

Electric Trailer Brake Assembly - Self-Adjusting - 12" - Right Hand - 5,200 lbs to 7,000 lbs

(351)

$68.18

Trailer Hub and Drum Assembly - 5,200-lb and 6,000-lb Axles - 12" - 6 on 5-1/2 - Pre-Greased

(1220)

$145.14

Hydrastar Electric Over Hydraulic Actuator for Drum Brakes - 1,200 psi

(73)

$909.94

4" Carbon Fiber Digital Caliper

(26)

$12.23

Question:

With the existing brake setup on the M105A2 trailer, is it possible to use the HBA10 in conjunction with the existing brakes from the air diaphram back? The brakes are in good working order, I just do not have air brakes on the towing vehicle. I will be towing with a 2005 Ford F-250. I saw the solution using all new bearings, hub, and drums, but was wondering if there is a way to use existing equipment. Thanks for you help in advance

asked by: William B

Expert Reply:

We've had this question before and we were able to determine that your M105A2 either uses a 5200 lb or 6000 lb axle so for hub drums you most likely will need the part # AKHD-655-6-K. This hub and drum comes with inner bearing part # 25580 and outer bearing part # 15123. It fits a 12 inch diameter brake assembly. You do want to check your existing bearings for their bearing numbers. There should be bearing numbers stamped on the side. If there is not numbers stamped on the side you can measure the bearing with a digital caliper like part # PTW80157. The inner bearing of the hub I mentioned measures 1.378 inches and the outer bearing measures 1.063 inches.

Then for brake assemblies you'd want the # AKEBRK-7R-SA for the right hand side and part # AKEBRK-7L-SA for the left hand side.

I also attached a help article that covers converting a trailer to electric brakes for you to check out as well.

expert reply by: Jameson C

click to enlarge

William B.

11/6/2019

Jameson C.

11/6/2019

If the hydraulic pressure rating of the assemblies you have on your trailer are 1,000 psi then the # HBA-10 would be able to actuate them. If instead the pressure rating is 1,200 lbs then you'd need the part # HBA-12 instead. We don't have a way to look up the pressure rating of the assemblies so you'd need to see if you can find that info listed on the assemblies or if you can find part numbers on any of the components that might lead you to the correct info.