The time it takes to replace the brake lining on a truck can vary depending on several factors such as the size and type of the truck, the complexity of the brake system, and the expertise of the mechanic performing the replacement. Generally speaking, replacing the brake lining on a truck can take anywhere from a few hours to a full day.

If the brake lining replacement is a routine maintenance task and there are no complications, it can take about 2-4 hours to complete for a single axle truck. For larger and more complex vehicles, such as tractor-trailers or heavy-duty trucks, the job may take longer, up to a full day.

It's important to note that the time it takes to replace brake lining can vary depending on the condition of the brake system, the type of replacement parts used, and the skill level of the mechanic performing the work. Additionally, other maintenance tasks, such as replacing brake pads or calipers, may also be necessary and can add additional time to the overall job.