This DX16.5 model heavy-duty hydraulic trailer surge brake actuator from UFP by Dexter is a common trailer brake actuation system compatible with a variety of large tandem axle and single axle boat trailers. The surge actuator was formerly called the Model A-160 or A165, but is now manufactured by Dexter. The actuator still features a unique over-center latch mechanism that will only engage when the actuator is fully seated on the 2 5/16″ towing ball, so it is convenient and easy to attach and unattach your boat trailer to your vehicle’s tow hitch. The surge coupler unit has a towing weight capacity of 16,500 lbs, so you will frequently see this surge actuator used with heavy trailers outfitted with one or two braked axles, typically 7,000-8,000 lb capacity 8 lug axles. The zinc-plated finish of the hydraulic actuator makes it ideal for use on both freshwater and saltwater boat trailers, while the aluminum master cylinder housing further prevents pre-mature rust and corrosion affecting the actuator’s internal components.
A Surge Disc Brake Actuator works by using the force of the towing vehicle stopping to engage the master cylinder, applying pressure on the brake fluid to flow through the brake lines. This particular actuator features a pre-installed reverse lockout bypass solenoid. The job of the reverse lockout is to allow you to go in reverse with your trailer without locking the brakes out. Two wires run from it, one as a ground, and the other connects to your wiring harnesses 5th wire (for 5 Flat connectors). This wire is commonly blue. Under normal operation while driving forward and braking the Reverse Solenoid Valve does nothing, however, once you need to reverse or back onto a boat ramp, the Solenoid Valve becomes crucial. When you put your truck in reverse, a signal is sent to the reverse lockout solenoid (through the 5th wire, which on the truck side connects to your vehicles reverse light) and the device blocks the flow of hydraulic fluid, this allows you to reverse without the surging of the trailer brakes stopping you as you go backwards down the ramp. Keep in mind this means as you reverse, your truck is your only source of braking.
Typically you will be using (4) 1/2 inch Diameter by 5 inch Long Stainless Steel Trailer Bolts to mount to your trailers 3 inch wide tongue. You must have a straight, 4 inch wide tongue to mount this DX16.5 (formerly A160) actuator. It is not uncommon to need to drill new holes, as different manufacturers use different bolt spaces when the tongue actuators are produced.
When installing a new disc brake system on single or tandem axle disc brakes it is not uncommon to spend extra time priming the lines, and using a good amount of brake fluid. It is important to begin at the furthest away caliper when trying to get the fluid through the lines and out the caliper bleeder. This style of UFP / Dexter A-160 / DX16.5 actuator is a popular style and brand of actuator used on large boat trailers that are made by a wide range of manufacturers, including Karavan, EZ Loader, Trailer Master, Ranger, Triton, and more! If you have a large boat trailer with a tandem axle 8 lug setup that needs a fresh new actuator this DX16.5 from UFP by Dexter might be just what you are looking for!
Specifications:
- Top Mount (slides over your 4″ wide tongue)
- Uses 2 5/16 inch Trailer Tow Ball
- Housing Dimensions: 25.75″ Long x 4.25″ wide x 6.18″ high. Zinc Finish. 8 mounting holes (3″ On Center)
- Maximum Tongue Weight 1,000 lb
- Former UFP A-165 Model
- Built in 3″ Drop
- Uses DOT 3 Brake Fluid
