Check the listing for details. Rb1140 Auto Slack Adjuster. Condition: New. Listed at 54.00 USD. The Rb1140 Auto Slack Adjuster is a commercial truck part designed to regulate the braking force and improve overall brake performance. This product is specifically designed for use in commercial trucks, providing accurate and reliable adjustments to ensure optimal braking efficiency. With the RB1140 Auto Slack Adjuster, truck drivers can enjoy smoother and more responsive braking, enhancing safety and control on the road.