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.
What Is a Brake Booster? Brake boosters are used only on power brakes, not manual brakes. The booster's function is to give more braking power with minimal pressure on the brake pedal. If the booster is not working properly, you will still have brakes, but the brake pedal will be very hard to push. A brake booster is what gives power brakes their power. It works on vacuum from the engine. The booster pushes on the master cylinder with the pressure applied to the booster by stepping on the brake. If the engine is off, it cannot get vacuum, therefore the brakes will be hard when the engine is off.