9-inch Hydraulic Backing Plate

9-inch Hydraulic Backing Plate

The 9-inch Hydraulic Backing Plate is a common brake system for trailers, caravans, and horse-floats.

Commonly known as AL-KO-style, this backing plate is often used as a ‘universal’ replacement. It is supplied as a complete new assembly, with new brake shoes and new wheel cylinders. Often, it is easier to replace the entire assembly with a new backing plate rather than replacing individual parts.

Backing plates used on trailer and caravan brakes are similar to those seen in the automotive industry. Backing plates are great as they are reliable, efficient, and easy to replace.

Product Specifications

• SKU/s: 311100 (Right), 311101 (Left)
• Cylinder Type: Dual Piston
• Dimensions: 9″ x 1 3/4″

N.B. Does not replace WestCo backing plates.

When mounting the backing plates, ensure that the wheel cylinder bleed nipple sits at the top of the drum. This is because air rises to the top of the brake cylinder and is released during bleeding.

Tip: The right-side plate replaces the driver’s side, and the left-side replaces the passenger’s.

How to Adjust 9″ Hydraulic Drum Brakes

Adjusting your drum brake shoes is a fairly simple but important task.

Generally, most mechanics will recommend adjusting your brake shoes after the first 500km travelled and every 5000km thereafter. An easy way of keeping track of this is through installing a Bluetooth Hub-Odometer.

To adjust your hydraulic drum brakes, follow the steps below:

1. Apply the foot brake three times. If there is a handbrake fitted, ensure this is released.
2. Check that the wheel and drum rotate freely. If it does not, check the default adjustment.
3. Locate the two, large hexagonal-shaped bolts. These will be found on the back of the backing plate on the left and right side (3 o’clock and 9 o’clock).
4. Turn one hexagon bolt clockwise until the wheel is very difficult to turn. You will need to use a ring spanner.
5. Back off until wheel spins with only a slight drag in the lining. Repeat for the second shoe by adjusting the second hexagonal bolt.
6. Apply the foot brake again three times. You will then need to repeat adjustment of the two hexagon bolts as you did previously.
7. Repeat this process for all wheels.

How do Hydraulic Brakes Work?

Hydraulic brakes are simple yet effective. In broad terms, it functions by transmitting force applied at one point to another by incompressible fluid.

When you apply the foot brake, the wheel cylinder forces brake fluid into the backing plate. Because it is incompressible, this fluid then causes pressure to force your brake shoes to expand and make contact with the brake drum. This generates friction, which is what causes your trailer to brake.