BOLT 2907514 - Caterpillar

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.
Illustration 1 g02698343
Typical location of engine crankcase breathers
Illustration 2 g00597463
Loosen clamp (1). Slide the clamp down on tube (2) .
Loosen clamps (3). Remove both breathers as a unit.
Illustration 3 g00597465
Remove O-ring seals (4) from the valve covers. Inspect the O-ring seals for good condition. Obtain new O-ring seals, if necessary.
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Remove two clamps (6). Remove both breathers (5) from hose tee (7) .Inspect the hose tee for cracks. If the tee is cracked, discard the old tee and obtain a new tee for installation.
Turn the breathers upside-down in order to inspect the condition of the breather elements.Clean the breather elements with clean, nonflammable solvent. If the breather elements remain contaminated after the cleaning, discard the breathers and obtain new breathers. Do not attempt to disassemble the breathers.Allow the breather elements to dry before installation.Note: Coat the rubber parts with clean engine oil or petroleum jelly in order to make installation easier.
Place clamps (6) over the parts of hose tee (7) that will receive breathers (5). Install the breathers into the tee. Tighten the clamps to the torque that is listed in the Service Manual, "Specifications".
Coat O-ring seals (4) with clean engine oil. Place the O-ring seals on the valve covers.
Place clamps (3) around the parts of the breathers that will be attached to the valve covers. Install both breathers as a unit. Tighten the clamps.
Place clamp (1) on the part of the hose tee that will receive tube (2). Install the tube into the hose tee. Tighten the clamp to the torque that is listed in the Service Manual, "Specifications".