Demco Hydraulic Drum Brake Assembly - Free Backing - Galvanized - 12" - Right Hand - 7,000 lbs

Demco Accessories and Parts - 42028

Free-backing, passenger's-side trailer brake assembly won't engage when you reverse, even if your hydraulic actuator is activated. Galvanized steel resists rust, making the assembly great for boat trailers. Mounting flange has 5-bolt pattern.

Features:

• Marine-grade hydraulic drum brake assembly is great for boat trailers
  • Designed for use with surge-type trailer brake actuators
• Sturdy, corrosion-resistant steel construction
  • Galvanized backing plate
  • Stainless steel spring hardware
  • Zinc-plated wheel cylinder
• Free-backing design lets you back up without engaging the trailer brake, even if the actuator is activated
  • Riveted, fall-away brake shoe only anchors on drum when brakes are engaged as trailer is moving forward
  • Periodic manual adjustment required
• Mounting bolts sold separately
• Made in the USA

Specs:

• Configuration: right hand (passenger's side)
• Dimensions: 12" diameter x 2" thick
• Mounting flange bolt pattern: 5 on 3-7/8"
• Wheel size: 14-1/2", 15", and 16"
• Axle rating: up to 7,000 lbs
• 1-Year warranty

Note: Because free-backing brakes are designed to eliminate nearly all friction between the brake shoes and the drum when you are driving in reverse, a trailer breakaway kit will not be effective should your trailer disconnect from your tow vehicle while you are backing up.

Free-backing brakes let your trailer move in reverse without the brakes being activated by your surge actuator. These brakes are needed if your actuator does not have a reverse lockout, which is a mechanism that ensures that the actuator does not activate when your rig moves in reverse.

Demco Free-Backing Brake with Fall-Away Shoe

This Demco free-backing brake assembly has a fall-away shoe that is designed to provide full braking action when your trailer is moving forward and to supply only limited friction when the trailer is moving in reverse. This is largely due to the incorporated dual springs at the shoe's pivot point. (One spring sits on either side of the shoe lever, so only a single spring is visible when looking at the brake assembly.)

When your rig is moving forward and you engage the trailer brakes, the fall-away shoe expands normally, with the leading edge of the shoe catching the drum. This occurs because the plunger on the hydraulic cylinder pushes on the shoe lever, forcing the leading edge of the brake shoe into the drum. Once that edge catches, the dual springs at the shoe's pivot point facilitate braking by forcing the rest of the shoe to pivot into the drum. The action of the shoe against the drum provides the friction required for braking.

When you are driving in reverse, however, the hydraulic cylinder and the springs work against one another. Even though the plunger pushes on the shoe lever, the dual springs of the fall-away shoe overcome the pressure from the brake cylinder, keeping the leading edge from catching on the drum and ensuring that the shoe does not fully pivot into the drum. Because the shoe makes only slight contact with the drum, just enough friction is generated so that only a minimal amount of braking occurs when you are in reverse.

SB42028M Demco Galvanized 12" Marine Trailer Brake Assembly - Freebacking - Right Hand