There are many types of U-Joints, some of which are incredibly complex. The simplest category known as Cardan U-Joints, happen to be either block-and-pin or bearing-and-cross types.
U-joints are available with two hub types solid and bored. Sound hubs don't have a machined hole. Bored hubs possess a hole and so are known as for the hole condition; round, hex, or sq . style. Two bored designs that deviate from these common shapes are splined, which have longitudinal grooves within the bore; and keyed, that have keyways to prevent rotation of the U-joint on the matching shaft.
Using the incorrect lube can bring about burned trunnions.
Unless usually recommended, use a high quality E.P. (intense pressure) grease to provider most vehicular, industrial and auxiliary drive shaft applications.
Mechanically flexible U-Joints accommodate end U Joint movement by simply using a telescoping shaft (sq . shafting or splines). U-Joints function by a sliding motion between two flanges that will be fork-shaped (a yoke) and having a hole (attention) radially through the attention that is linked by a cross. They allow larger angles than adaptable couplings and are used in applications where great misalignment needs to be accommodated (1 to 30 degrees).
Always make sure new, fresh grease is evident in all four U-joint seals.
Can be caused by operating angles which are too large.
Can be the effect of a bent or sprung yoke.
Overloading a drive shaft can cause yoke ears to bend. Bearings won't roll in the bearing cap if the yoke ears aren't aligned. If the bearings stop rolling, they stay stationary and can “beat themselves” in to the area of the cross.
A “frozen” slip assembly won't allow the drive shaft to lengthen or shorten. Each and every time the drive shaft attempts to shorten, the strain will be transmitted into the bearings and they will indicate the cross trunnion. Unlike brinnell marks due to torque, brinnell marks that will be the effect of a frozen slip are usually evident on leading and back areas of the cross trunnion.
Improper torque in U-bolt nuts could cause brinelling.
Most suppliers publish the recommended torque for a U-bolt nut.
Improper lube procedures, where recommended purging isn't accomplished, can cause one or more bearings to be starved for grease.