154011-1600 ZEXEL 9 421 610 410 BOSCH UNION NUT 9421610410 1540111600 1157290940

Crankcase Breather
Clean
This maintenance is to be performed every other oil change or 600 hours. 1. Loosen breather retaining clamp (1) on breather.2. Loosen hose clamp (2) and remove breather assembly.3. Wash breather in clean, nonflammable solvent and allow to dry.4. Install new seal.5. Assemble breather and install in reverse order of removal.6. Tighten all hose clamps (2) to 27 4.5 lb in (3.0 0.5 N m). If the crankcase breather is not maintained on a regular basis, it will become plugged. A plugged crankcase breather would result in excessive crankcase pressure that may cause crankshaft seal leakage.Refer to the Torque Specifications section of this manual for Torque for Standard Hose Clamps-Worm Drive Band Type hose clamps if your engine is equipped.Alternator, Fan and Accessory Drive Belts
Inspect/Replace
Inspect the condition and adjustment of alternator belts and fan drive belts.Inspect all drive belts for wear and replace if they show any signs of wear.If one belt in a set requires replacement, always install a new matched set of belts. Never replace just the worn belt. If only the worn belt is replaced, the new belt will carry all the load, as it will not be stretched as much as the older belts. All the belts will fail in rapid succession.Belt Adjustment
If belts are too loose, they vibrate enough to cause unnecessary wear on the belts and pulleys.If belts are too tight, unnecessary stresses are placed upon the pulley bearings and belts which might shorten the life of both.1. Inspect the condition and adjustment of alternator belts and fan drive belts.2. To check the belt tension, apply 25 lbs (110 N) of force midway between the pulleys. Correctly adjusted belts will deflect 1/2 to 3/4 inch (13 to 19 mm).Adjust Alternator Belts
3. To adjust the alternator drive belts, loosen mounting bolt(s) (1) and adjusting bracket nut(s) (2).4. Adjust the alternator in or out by either tightening or loosening adjusting nut(s) (2), as required, to obtain the correct adjustment.5. Tighten bolts (1) and nuts (2).6. If new belts are installed, check belt adjustment again after 30 minutes of engine operation. Replace belts in matched sets only. If only one belt of a matched set is replaced, it will carry more of a load than the belts not replaced since the older belts are stretched. The additional load on the new belt could cause it to break.Adjust Fan Drive Belts
7. To adjust the fan drive belts, loosen mounting bolts and adjust with adjusting bolt.8. Move the fan drive up or down as required to obtain the correct adjustment. Tighten mounting bolts.9. If new belts are installed, check belt adjustment again after 30 minutes of engine operation.Refer to the Service Manual for 3406 Truck Engines for more information or see your Caterpillar dealer.Hoses and Clamps
Inspect
* Inspect all hoses for leaks due to cracking, softness and loose clamps.* Replace hoses that are cracked or soft and tighten loose clamps.Before Replacing Hoses
1. After engine is cool, loosen the radiator filler cap slowly to relieve any