SPRING 9U9328 - Caterpillar

G3508 (4WD, 2JF, 9TG),
G3512 (4KC, 5JD, 7NJ),
G3516 (3RC, 8LD, 4EK, 5PN) EnginesReference: Engine News, September 1995, Page 5, "Serviceable Parts Available For Sprague Gas Pressure Regulator Assembly"Description of Change: Several internal improvements have been made to the high pressure gas regulator assembly on these engines. A new nylon coated valve stem is used in place of the former stainless steel valve stem. The nylon coated valve stem reduces the sliding friction between the valve stem and the bushing. The valve lever is now polished, in order to reduce friction. These modifications prevent premature wear to the internal regulator components, thereby eliminating sluggish regulator response. These regulator changes will improve engine performance under load swings, especially on regulators with high operating hours.
Locations on new and improved components in the improved 7E-3407 Gas Pressure Regulator Assembly. 123-3977 Diaphragm Plate (1). 123-3966 Valve Lever (2).173-4548 Valve Stem (3). Adaptable To: The part number of the improved 7E-3407 Gas Pressure Regulator Assembly has not changed. The improved 7E-3407 Gas Pressure Regulator Assembly includes the new 173-4548 Valve Stem (nylon coated) in place of the former 123-3971 Valve Stem. The 123-3966 Valve Lever is now polished, in order to reduce sliding friction between the valve lever and the 123-3977 Diaphragm Plate. The valve lever and the diaphragm plate will retain the same part numbers. See the illustration for locations of these parts. The improved 7E-3407 Gas Pressure Regulator Assembly is effective with the engine serial numbers listed in the chart. Earlier 7E-3407 Gas Pressure Regulator Assemblies can be rebuilt using the new 173-4548 Valve Stem. Current production G3508 (2JF) and G3516 (5PN) Engines do not utilize the 7E-3407 Gas Pressure Regulator Assembly, but the new parts can be used on these engines also. If an engine exhibits instability or poor response to changes in load, wear to these internal linkage parts is indicated. To determine if the internal regulator parts are worn, tap on the regulator case with a soft (rubber) hammer. If the engine speed increases or stabilizes after tapping the case, wear is evident in the parts. The regulator should then be rebuilt, using the new parts.