There are many types of U-Joints, some of which are extremely complex. The simplest category referred to as Cardan U-Joints, are either block-and-pin or bearing-and-cross types.
U-joints are available with two hub variations solid and bored. Solid hubs don’t have a machined hole. Bored hubs currently have a hole and so are known as for the hole condition; round, hex, or sq . style. Two bored types that deviate from these common shapes are splined, that have longitudinal grooves inside bore; and keyed, that have keyways to prevent rotation of the U-joint on the matching shaft.
Using the incorrect lube can cause burned trunnions.
Unless otherwise recommended, use a superior quality E.P. (intense pressure) grease to assistance most vehicular, professional and auxiliary travel shaft applications.
Mechanically flexible U-Joints accommodate end movement simply by utilizing a telescoping shaft (square shafting or splines). U-Joints function by a sliding movement between two flanges that will be fork-designed (a yoke) and having a hole (attention) radially through the eye that is connected by a cross. They enable larger angles than flexible couplings and are used in applications where huge misalignment should be accommodated (1 to 30 degrees).
Always make sure fresh, fresh grease is evident in all four U-joint seals.
Can be caused by operating angles which are too big.
Can be caused by a bent or sprung yoke.
Overloading a travel shaft can cause yoke ears to bend. Bearings will not roll in the bearing cap if the yoke ears aren’t aligned. If the bearings stop rolling, they continue to be stationary and can “beat themselves” in to the surface area of the cross.
A “frozen” slip assembly won’t allow the travel shaft to lengthen or shorten. Each time the drive shaft tries to shorten, the strain will be transmitted into the bearings and they’ll tag the cross trunnion. Unlike brinnell marks caused by torque, brinnell marks that happen to be the effect of a frozen slip are at all times evident on leading and back surfaces of the cross trunnion.
Improper torque upon U-bolt nuts could cause brinelling.
Most manufacturers publish the recommended torque for a U-bolt nut.
Improper lube procedures, where recommended purging isn’t accomplished, can cause a number of bearings to be U Joint china starved for grease.