DIE-SET 8T5128 - Caterpillar

Illustration 1: Typical Unit Fuel Injection Pump Sleeve. (1) 120 degree included angle surface where the lower injector O-ring seals.
Illustration 2: Typical Unit Fuel Injector. Entire lower portion of injector should be clean, especially (2) lower O-ring groove and adjacent surface.The preferred method of cleaning the sleeve bore is to:
* Place a 38 mm (1.5 in) square piece of "Scotch Brite" material on the end of 9U-6862 Small Tapered Brush.
* Hold and twist the brush with 4C-5027 Tap Wrench against the lower sleeve bore surface.
The use of power tools to rotate the material should not be necessary since carbon in this area is not as difficult to remove as at locations exposed to higher temperatures.* The surface should be cleaned until it is smooth and shiny. The entire sleeve bore should, then, be cleaned to remove any loose carbon particles.
It is advantageous to use 4C-6774 Vacuum Kit Gun, which is operated by compressed air, to clean the bore.