If the rust spots are evenly spaced, you can use surface stitches to cover them. Good stitches might be Smyrna cross stitch, satin-stitch heart, queen stitch, satin stitch lozenges/triangles, palestrina knots, etc. If the spots are not evenly spaced, balance the design by adding extra stitches between the spots.
Fortunately, most states require drivers to equip their trailers with brakes and devices known as brake controllers. When a driver presses on the brake pedal in his truck, the brake controller lets the trailer's brake system know how much braking power is needed to stop the trailer.
The actuator on an anti-lock brake system (ABS) is known as an ABS actuator. This is an electronic device that receives a signal from the vehicle's computer to control the brake pressure so that the wheels will not become locked up. The computer monitors the signals on a vehicle's braking system several 100,000 times per second, in some cases. When the computer senses that a brake is beginning to lock up, the ABS actuator adjusts the brake pressure being applied to the wheel and prevents the wheel from locking. Offered as an option on several models of vehicles sold worldwide, the anti-lock brake system is intended to avoid accidents related to wheels becoming locked as the brakes are being applied.