Why is the fifth wheel greased?
a.To prevent the kingpin from locking
b.To reduce friction and allow the trailer to turn freely on the fifth wheel
c.To keep rain water from pooling on the surface
d.To make the fifth wheel easier to inspect
Explanation
The fifth wheel is greased to reduce friction between the upper and lower fifth wheel plates. This allows the trailer to pivot and turn smoothly on the tractor. Without proper greasing, steering can be difficult and the plates can wear prematurely.