Description
The 8K 12-1/4″ x 3-3/8″ Hydraulic Brake Left Hand, Free-Backing, part #31-5120-HF, delivers reliable hydraulic stopping power for heavy-duty 8,000 lb trailer axles. This left-hand (driver side) assembly uses a 12.25″ x 3.375″ drum and shoe configuration that works well on equipment trailers, utility fleets, agriculture trailers, and commercial construction trailers that demand strong and smooth braking performance.
This hydraulic brake assembly bolts to a 4-bolt brake flange, making installation straightforward in both service shops and fleet maintenance environments. The unit replaces many Dexter 8K hydraulic brake assemblies as well as other OEM axle brands using the same 12-1/4″ x 3-3/8″ left-hand hydraulic footprint. The free-backing design prevents the shoe linings from dragging when the trailer backs up, reducing wear and allowing tight maneuvering in yards, job sites, and loading zones.
The 31-5120-HF arrives pre-assembled with hydraulic wheel cylinder, bonded brake linings, return springs, and free-backing hardware already installed. Service technicians and repair facilities appreciate this format because it minimizes downtime and delivers an out-of-the-box solution for replacing worn brake systems on heavy-duty trailers.
To unlock full braking performance, break in (burnish) the brake assembly immediately after installation. Tow the trailer in a controlled environment and use repeated, moderate stops from a stable speed. Avoid harsh panic stops during burnishing. This process seats the shoe linings to the drum surface and maximizes hydraulic braking efficiency under load.
Customers searching for 8K hydraulic trailer brakes, Dexter-compatible hydraulic brake parts, and heavy-duty free-backing brake assemblies find part #31-5120-HF a dependable solution. Fleet operators, trailer dealers, and equipment rental companies rely on this left-hand hydraulic brake assembly to restore stopping power and maintain safe operation.
Additional Part # K23-402-00, 23-402, 23-138, BK-8KH-01
Reviews
There are no reviews yet.