What causes a rear wheel to lock up?
Brake shoe contamination can be the cause of rear wheel lockup. If an axle seal or wheel cylinder leaks and contaminates the brake shoe(s) it changes the coefficient of friction. If it is mild contamination then the friction is increased while severe contamination will cause a reduction in friction (See Figure 61.9).
What does it mean when the wheels lock up?
Lock up essentially means that the braking force exceeds the frictional force that is keeping the tire in motion. It is usually caused braking while cornering due to the load transfer in the corner. The weight of the car is mostly onthe outside tires in the corner, so the frictional force on the inner tire is less.
What can cause a rear wheel lockup problem?
Rear wheel lockup problems come in two broad categories. The first and most common are those caused by mechanical problems in the rear brakes. The second are those caused by hydraulic problems in the system.
What to do if your lawn mower rear wheel is locked up?
If you’re thinking you should be doing something with the transmission, forget that. Your problem is in the rear wheel bearings. So the fix is cleaning out and lubricating the rear wheel bearings. Once we got the mower put back together, we added gas and oil and shared a look of hopeful anticipation.
Can a out of round drum cause rear wheel lockup?
Brake drum condition should be factored in when determining the cause of rear wheel lockup. An out of round brake drum or drums that vary in diameter too much from side to side could cause a one wheel lockup condition (Figure 61.8). Measuring drum runout or out of roundness is not easy in the field.
Why does my drum brake lock up at the rear?
One of the most common causes of one or two wheel lockup on drum brake equipped vehicles is the service and/or parking brake adjustment. If either one or both of these adjustments are done incorrectly it can result in the rear brakes being very sensitive.