Cleaning.

(2) Inspect the idler sleeve bearings for pitting,

Be careful not to damage the metal floating ring

roughness and wear. The specified shaft to bearing

seals as they are removed.

clearance is 0.008-0.012 inch. The maximum

(4) Tape each pair of seals together to prevent

allowable shaft to bearing clearance is 0.050 inch.

intermixing them with other seals.

The specified shaft and clearance is 0.011-0.029

NOTE

inch. Replace pitted, rough, or excessively worn

When installing bearings (1) and (4), apply anti-seize

compound in bearing bores and on bearing contact

bearings.

surfaces of shaft (5).

( 3 ) Inspect the idler shaft for pitting,

roughness, and wear. Replace a damaged, ex-

(5) Remove collars (3) from both sides of idler.

cessively worn, or bent idler shaft.

(4) Inspect the metal floating ring seals for

damage and proper wear pattern. Replace seals

which are pitted, grooved, scratched across the seal

surface, or which show an uneven wear pattern.

Seals must be replaced in sets.

(5) Replace all toris sealing rings. Do not reuse

toric seal rings.

(6) Inspect bearings, guides, and collars for

cracks, breaks, or other damage. Repair by welding

and grinding smooth or replace the part.

e. Reassembly.

(1) Reassemble in the reverse order of

disassembly.

(2) Install floating seals (2) using a metal seal

installer assembly. Follow procedure outlined in

paragraph 6-22.

NOTE

At assembly tighten the nuts on the tapered pins to the

initial torque given in table 1-2. Use a hammer and

punch to seat the tapered pins and then tighten the

nuts to the final torque value.

Bearing

Floating duo-cone seals

(3) Lubricate the idler.

Collars (2)

f. Installation.

Bearing

(1) Install the idler in the reverse order of

Shaft

rem oval.

Bushing assemblies (2)

(2) Align the idler with the track rollers (para

Figure 7-19. Front idler disassembly.

7-5).

c. Cleaning.

g. Repositioning Front Idler.

(1) Clean all parts using cleaning solvent (Fed.

NOTE

Spec. P-D-680) and dry with lint-free cloth.

The idler can be positioned from the HIGH to LOW or

(2) Remove all dirt and rust from the floating

LOW to HIGH position.

ring seal mounting grooves. Grooves must be clean,

(1) Remove the idler. Note the location of the

smooth, and dry.

recess, with the bearing in the LOW position (fig. 7-

(3) Wash protective coating from new ring

20).

seals with cleaning solvent.

(2) Rem ove the bolts, raise collars and revolve

d. Inspection and Repair.

bearings and shaft 180 so recesses are toward the

(1) Inspect the front idlers for damage and

rear of tbe machine (fig. 7-21 ). Install the bolt.

wear. When the contact surf act of the idler is worn

(3) Rotate the idler 180 in the direction

to the extent that the center flange height measure

indicated by the arrows. This will position the idler

from 1.07-1.24 inches, the idler will be repaired

properly for installation in the HIGH position. The

by welding an overlay on the wear surface. Idlers

bearing that was previously on the right side of the

worn to the extent that the center flange height

idler will now be on the left, and the recess will

measures 1.24 inches or more, will be replaced.

again be toward the front of the machine.

Idler center flange height new is 0.88 inch.

7-11