D346, D348 & D349 VEHICULAR ENGINES Caterpillar

(7)Crankcase Breather

1. Loosen the hose clamp (A) and the cover bolt (B).

2. Remove the breather cover.

3. Remove and inspect the breather element.

4. Wash the breather in clean nonflammable solvent.

5. Install the breather element and cover. Connect the hose.

(8)Fan Drive And Alternator Belts

1. Check the belts for excessive wear, fraying and cracking.

When belt replacement is necessary, belts must be replaced in complete matched sets. Never replace only one belt. The new belt will carry all the load and fail rapidly.

2. Apply a 25 pound (110 N) force perpendicular to the belt, midway between the driving and driven pulleys. Measure the belt deflection.

Proper belt deflection is 9/16 to 13/16" (14 to 20 mm). Adjust the belt tension if required.

To Adjust Fan Drive Belts

1. Loosen the four nuts (A) holding the fan mounting plate to the engine.

2. Loosen the locknut (B). Turn the adjusting screw (C) until the belt is properly adjusted.

3. Tighten the four mounting nuts (A) and locknut (B).

4. Check the belt adjustment. If adjustment is not correct, repeat steps 1 through 3.

To Adjust Alternator Belts

1. Remove the belt guard.

2. Loosen the locknut on the belt tightener rod.

3. Turn the adjustment nut until correct belt deflection is obtained.

4. Tighten the locknut.

5. Check the belt adjustment.

6. Install the belt guard.