1942 - 1947 Chevrolet Shop Manual



	8-1

	*Section 8* FUEL TANK AND EXHAUST SYSTEM

	FUEL TANK PASSENGER CARS AND SEDAN DELIVERY The fuel tank on these models consists of two shallow pans, each with a wide flange. The pans. set face to face, are seam welded at the flanges around the entire tank to assure leak-proof construction. Exceptional stiffness is secured by the combination of the welded flanges and depressed ribs in each of the pans. On all 5-passenger cars the fuel tank is mounted by straps to the underbody of the trunk compartment to insure sufficient road clearance. The outlet pipe and that portion of the feed pipe connecting to the outlet pipe flange have a downward slant toward the tank, to eliminate the possibility of water or moisture accumulating at this point. Upper and lower filler necks are so treated that rust will not get into the fuel supply. To remove the tank, disconnect the filler neck at the coupling. Then disconnect the main gasoline pipe and the gasoline gauge wire. Remove the strap bolts, nuts, washers and spacers and lower the tank. The fuel tanks on the Business Coupe and Sedan Delivery incorporate baffle plates which act as stiffeners and prevent the surging of gasoline within the tank. The general construction of the Business Coupe and Sedan Delivery fuel tank is quite similar to that used on other passenger cars, however, it is mounted differently to make better use of the load-carrying space in these models. The tank is located crosswise under the loading floor, resting on two wooden spacers which are bolted lengthwise to the floor pan. Two straps in line with the spacers clamp the tank rigidly in place. At the front end, each strap hooks into a bracket which is bolted to the wooden riser behind the seat and is also welded to the floor pan. The rear of each strap is attached to an eye bolt that extends through the spacer and the floor pan. The filler passes through the body panel just ahead of the rear fender on the curb side of the car. The tank is readily accessible through the cover board in the loading floor. In replacing the tank care should be used to make sure that the sponge rubber seal at the outlet is in place and that the sponge rubber mat is properly located on top of the tank.	This mat compresses against the top of the tank and guards against noise at this point. FUEL TANK FILLER CAP To prevent spilling of gasoline when making sharp turns or traveling on rough roads, a device, consisting of a baffle cup and a vent pin is incor-porated in the filler cap, Fig. 1. Through this arrangement the vent area is reduced to a minimum, yet is large enough to serve as a breather for the fuel tank. The small vent area is accomplished by inserting a special pin in the breather holes which are kept open by the bouncing or "jiggling" action of the pin. This minute area, if pierced in the outer part of the cap as a separate hole, would soon be clogged by dirt or corrosion.

		Fig. 1—Fuel Tank Filler Cap The device not only controls the flow of gasoline, but also traps in the baffle cup any that might escape through the lower vent. The chamber volume is adequate for the ordinary overflow, which subsequently returns to the tank. A small hole is provided at the top of the chamber to complete the breather system. A slight clearance must be maintained between the filler cap and the rubber grommet around the filler neck, particularly on passenger cars, to prevent the cap "bottoming" or sealing against the rubber. When this occurs, the vent is cut off en-