Fig. 121. Full-Floating Axle
Two types of front axles are used by the manufacturers of automobiles. The I-beam type, which is a one piece drop forging, and the tubular or hollow type, which is round and has the yoke fitted into the ends. Both types operate on the same principle and plan, the only distinction between the types is that one type has the I-beam cross member and the other type has a pipe or tubular cross member.
Fig. 122. Steering Knuckle and Front Axle Parts
The front axle consists of an I-beam or tubular cross member, which is yoked at each end as shown at A, in [Fig. 122]. A steering knuckle B is held between the ends of the yoke by C, a king pin, which allows the knuckle to swing in a half circle. D, the spindle or short axle, is provided with a set of radial thrust bearings. The wheel is adjusted snugly to the bearings E by a castillated nut F. The adjustment is held by a cotter pin which extends through the spindle and head of the nut F. A short arm extends backward from each steering knuckle, shown at G, in [Fig. 122], and are connected together by an adjustable tie or spread rod shown at H. A half circle ball arm extends from the knuckle and circles over the axle. A rod or drag link forms the connection between the ball arm and the steering arm of the steering gear. [Fig. 123] shows the location of the parts assembled on a typical drop forged I-beam front axle. A section of the hub has been removed to show the location of the double row radial end thrust ball bearings. This type of bearing is becoming very popular for automobile uses.
Adjustments of the Semi-floating Type of Axle.—The short shaft carried in the forward part of the housing has a center nut adjustment between the universal joint and the pinion gear; moving this notched nut to the right facing the rear axle draws the shaft backward and meshes the teeth of the pinion gear deeper with the teeth of the ring gear. After this adjustment is made, examine the teeth for even mesh; it may be necessary to shift the differential unit to secure an even bearing. (See chapter on [differential gears] for detailed instructions in regard to differential adjusting.)
Fig. 123. I-Beam Front Axle
Adjustments on the Full-floating Axle.—The adjustments on the full-floating axle are usually made by shifting the differential unit, although a pinion gear adjustment is usually provided as described above.
Care.—The housing of both the semi-floating and the full-floating axle should receive a fresh supply of medium fiber or graphite grease every thousand miles. To grease, remove the plug on the large part of the housing and force in grease with a dope gun until it begins to bulge out of the hole.