Demco Trailer Brake Actuators

Demco Trailer Brake Actuators: Surge-Braking Engineered for Every Load

When it comes to hydraulic surge brake actuators, Demco Trailer has built one of the most respected and comprehensive lineups in the industry. Covering a wide spectrum of towing needs, Demco's brake actuators are available in GVWR ratings from 6,000 lb. all the way up to 20,000 lb., making them suitable for everything from lightweight boat trailers to heavy commercial rigs.

How Demco Surge Actuators Work

All Demco brake actuators operate on the hydraulic surge principle: when the tow vehicle decelerates, the forward inertia of the trailer pushes against the actuator's inner slide, which in turn pressurizes the master cylinder and applies the trailer brakes proportionally to the rate of deceleration — with no brake controller required. This seamless, self-regulating design makes Demco actuators a popular choice among boat owners, RV enthusiasts, and commercial operators alike.

The Demco DA Series — A Model for Every Application

Demco's DA Series covers a broad range of trailer types and weight classes, each engineered with specific applications in mind:

• DA66 & DA70 (6,000–7,000 lb. GVWR): Zinc-plated for marine environments, these models feature a lever lock design and are available for both drum and disc brakes. The DA70 uses Demco's signature EZ Latch coupler for quick, confident hookups, while disc brake versions include a reverse solenoid and cover.
• DA86 (8,600 lb. GVWR): Built for marine and light utility use, the DA86 features a reinforced outer case, large rear rollers, and a 2" EZ Latch coupler — combining durability with ease of use.
• DA91 (7,000–8,000 lb. GVWR): A versatile drop-style actuator available in multiple coupler configurations — slide-lok, EZ Latch, channel, and flat plate — compatible with an optional manual reverse lockout kit.
• DA10 (12,500 lb. GVWR): Supports both disc and drum brakes and offers a wide variety of mounting options, including 2 5/16" EZ Latch, 6" 2-bolt channel, 8" 4-bolt channel, and 12" 6-bolt channel configurations.
• DA16 (16,000 lb. GVWR): Available in weld-on and bolt-on mounts, with a maximum tongue load of 1,600 lb. — ideal for heavier utility and commercial trailers.
• DA20 (20,000 lb. GVWR): Demco's heaviest-duty offering, featuring a 50-degree A-frame weld-on option, 3" inside dimensions, and an optional 1-1/4" bore aluminum master cylinder for higher line pressures required when running three or more axles.

What Sets Demco Actuators Apart

Demco's attention to engineering detail runs throughout every model in the DA Series. Standard composite master cylinders — made of long glass-reinforced nylon — eliminate rust and corrosion from the fluid circuit. An automotive-style diaphragm in the master cylinder cap creates a fully enclosed brake system that prevents fluid contamination, while a raised fill plate and bellow boot on the push rod add further protection against moisture and debris. Zinc-plated steel housings on marine-grade models provide reliable corrosion resistance in saltwater and freshwater environments. For disc brake models, lockout solenoids allow the braking system to disengage automatically during reverse maneuvers. Demco also offers unassembled actuator kits for the DA91, DA10, and DA20 — a practical option for builders and DIYers who prefer to weld, prime, and paint before final assembly.

Whether you’re outfitting a boat trailer, a heavy utility hauler, or a multi-axle commercial rig, Demco’s DA Series provides a precisely engineered, durable hydraulic surge solution backed by decades of trailer component expertise.