BOSS 9R0203 - Caterpillar

Perform this maintenance with the engine stopped.
If the crankcase breather is not maintained on a regular basis, the crankcase breather will become plugged. A plugged crankcase breather will cause excessive crankcase pressure that may cause crankshaft seal leakage.
Unlatch the engine hood. Raise the engine hood.
Illustration 1 g01127724
(1) Outlet hose
(2) Hose clamp
(3) Clamp for the breather
(4) Breather cover
Loosen the hose clamp (2). Disconnect the outlet hose (1) from the breather (4).
Loosen the clamp for the breather (3). Remove the breather and the seal. Note: Refer to Operation and Maintenance Manual, "General Hazard Information" for information on containing fluid spillage.
Wash the breather in a clean, nonflammable solvent.
Inspect the seal. If the seal is damaged, install a new seal.
Install the O-ring seal and the clean breather. Tighten the clamp for the breather.
Slide the hose onto the breather. Tighten the hose clamp.
Close the engine hood. Latch the engine hood.