Figure 12-23. - Patterns of tire wear.

2. Shimmy at low speeds:

a. Low or uneven tire pressure

b. Loose linkage

c. Worn ball joints

d. Caster incorrect or uneven

3. Vehicle wanders:

a. Tire pressure incorrect or unequal

b. Caster or toe incorrect excessively worn

c. Suspension components or damaged

4. Steering wheel not centered:

a. Toe-in out of adjustment

b. Steering components bent

c. Steering wheel not properly placed on steering shaft

5. Steers hard:

a. Low tire pressure

b. Binding steering assembly or misadjusted

c. Excessive caster

d. Steering and suspension units not properly lubricated

6. Tire wear (fig. 12-23):

a. Underinflation causes wear at tread sides

b. Overinflation causes wear at tread center

c. Excessive camber causes wear at one tread side

d. Excessive toe-in or toe-out on turns causes tread to featheredge

TRACK ALIGNMENT

A misaligned front idler or track frame will cause many hours of project lost time and could cost several hundred dollars to replace worn-out components. You must know what components will be affected and what is involved in the proper alignment process. So, when this condition does arise, you will be able to diagnose it properly and take the corrective action needed to keep your equipment in the field and on the job.

Track frame misalignment can allow tee-out. This could cause excessive end wear of track pins, rail side wear and sprocket tooth gouging of the inside of the links, side wear of the sprocket and sprocket teeth, off-center external wear of the bushings, and flange wear of rear rollers. Misalignment of the front idler can cause wear of the front idler flange, the front track roller flanges, and the link side rails.

The use of track guiding guards keeps the track in proper alignment. These are called wear bars and plates. They are shimmied to align the idler with the track rollers. The side wear plates guide the idler, as it recoils back and forth. These guards should be reconditioned or adjusted to proper thickness, so they will guide the track squarely into alignment with the track rollers.

The front guiding guards receive the track from the idler and hold it in line for the first roller. The front roller then can be used fully for its intended purpose-that of carrying its share of the tractor load without having to climb the sides of the improperly aligned track.

The rear guiding guards hold the track in correct alignment with the driving sprocket, permitting a smooth, even flow of power from the sprocket to the track. With proper alignment, the gouging of link sides and sprocket teeth is eliminated.