maintenance — TRAILERS
The following trailer maintenance guidelines are intended to assist the operator in preventive maintenance.
Trailer Brakes
Properly functioning brake shoes and drums are essential to ensure safety. The brakes should be inspected the first 200 miles of operation. This will allow the brake shoes and drums to seat properly. After the first 200 mile interval, inspect the brakes every 3,000 miles. If driving over rough terrain, inspect the brakes more frequently.
hydraulic Brakes
If your trailer has hydraulic brakes, they function the same way the surge brakes do on your tow vehicle.The hydraulic braking system must be inspected at least as often as the brakes on the tow vehicle, but no less than once per year. This inspection includes an assessment of the condition and proper operation of the wheel cylinders, brake shoes, brake drums and hubs.
Manually Adjusting the Brakes
Most axles are fitted with a brake mechanism that will adjust the brakes during a hard stop. However, some braking systems are not automatically adjusted by hard stopping. These brakes require manual adjustment. The following steps apply to adjust most manually adjustable brakes.
1.Jack up the trailer and secure it on adequate capacity jackstands.
2.Be sure the wheel and brake drum rotate freely.
3.Remove the
4.With a screwdriver or standard adjusting tool, rotate the starwheel of the adjuster assembly to expand the brake shoes. Adjust the brake shoes out until the pressure of the linings against the drum makes the wheel very difficult to turn. Note:Your trailer maybe equipped with drop spindle axles. See axle manual for your axle type. You will need a modified adjusting tool for adjusting the brakes in these axles. With drop spindle axles, a modified adjusting tool with about an 80 degree angle should be used.
5.Rotate the starwheel in the opposite direction until the wheel turns freely with a slight drag.
6.Replace the
7.Repeat the above procedure on all brakes.
8.Lower the trailer to the ground.
Check the fluid level in the master cylinder reservoir at least every three months. If you tow your trailer an average of 1,000 miles per month in a hot and dry environment, you must check the brake fluid level once a month. The brake fluid reservoir is located on the tongue of the trailer. Always fill with clean, uncontaminated DOT 4 brake fluid.
Figure 14 below displays the major hydraulic brake components that will require inspection and maintenance. Please inspect these components as required using steps 1 through 6 as referenced in the “Manually Adjusting The Brakes” section on this page. See Table 4 for Hydraulic Brake Troubleshooting.
Figure 14. Hydraulic Brake Components
Hydraulic Brake Actuator
The hydraulic brake actuator (Figure 15) is the mechanism that activates the trailer’s brake system. This actuator changes fluid power into mechanical power.Therefore, the fluid level must be checked frequently to assure that the brakes function properly.
HYDRAULIC
BRAKE FLUID
RESERVOIR
Figure 15. Hydraulic Brake Actuator
page 24 — MLT25 sERIES LIGHT TOWER • operation manual — rev. #0 (11/28/12)