Here are some tips on how to achieve a properly maintained trailer air suspension system, which provides the best ride, correct load-carrying capability, and the required amount of roll control. As time passes, the suspension system will require attention as the bolt torque will loosen, the bushes will progressively wear, and components will accumulate debris from the road.
Harsh road conditions or off-road conditions will further accelerate debris accumulation and component wear. For this reason, it is important to keep the unit on a periodic maintenance schedule.
The suspension system in a trailer may vary depending on the application and trailer manufacturer. Please note that the following instructions are general in nature. Actual maintenance should be performed as per the trailer or the suspension system OEM service manual. Each will vary with inspection, adjustment and replacement intervals.
To begin, a simple visual inspection will help identify which components require further investigation. Accumulated debris can act as an abrasive and, over time, prematurely wear the components causing failure. Any signs of heavy dust or debris should be cleaned from the air springs, hub seals, and shocks. While doing so, take note of any physical damages, worn components or leaks.
- Air springs will sag and leak with an audible hissing sound, if severe enough. Also, be sure to check the air lines and fitting for slow leaks. When checking the air lines, firmly hold and wiggle the lines at the fitting. This will ensure the lines are secured and no leaks occur during movement.
- If a hub seal is leaking, a large quantity of lubricant will be present. Oil and grease may be splattered on the dust shield, brake shoes or brake drum. If this is the case, then the seal and other components will need to be replaced. A small amount of weeping lubricant is not considered to be a leak and can be wiped off. Never clean a hub seal with a pressure washer as water may enter the hub and contaminate the lubricant.
- There is a significant difference between a leaking shock and a misting shock. A misting shock will have a light coat of oil; in contrast, a leaking shock will appear to have streaking oil or oil paths. Please refer to the National Heavy Vehicle Regulator (NHVR) guide lines for more detailed information.
Last, but not least, checking ride height is a simple procedure to keep the suspension running at optimum performance. Most OEMs suggest taking a measurement from the centre of the axle to the bottom of the chassis frame.
Overall, periodic maintenance is essential to reduce the risk of component failure, address potential safety hazards, and prevent costly repairs.