SEAL-D-RING 3273965 - Caterpillar

Introduction
Do not perform any procedure in this Special Instruction until you have read the information and you understand the information.Cleaning Procedure
When cleaning the sensor passages in 380-8541 Venturi Tube or 420-3300 Venturi, the following procedure should be used.
Remove the delta-P and absolute pressure sensors from the venturi.
Bulk of material in the passages can be removed by hand turning a 15/64" drill bit through all three passages.
The 15/64" drill bit will leave a thin residual layer of material in the passage. This residue must be removed. To remove the residue, use a Dremel 455 stone (or equivalent) on a hand drill or rotary tool to clean the passage down to the parent material.
Final cleaning of the passages can be done with a cotton swab (or equivalent).
After cleaning of the sensor passages, use of cleaning fluid to remove deposits from the throat of the venturi is acceptable but not required.
Reinstall delta-P and absolute pressure sensor.