DETROIT DIESEL Engine systems The fuel pump incorporates two oil seals. Two tapped holes are provided in the underside of the pump body to permit draining off any leakage of oil.. If fuel leakage exceeds one drop per minute, the seals must be replaced. An authorized Detroit Diesel Allison Service Outlet is properly equipped to replace the seals. The fuel pump used on the V-71 engines is a left-hand rotating pump. Regardless of engine rotation, the pump will always rotate in a left-hand direction. Fuel Strainer and Fuel Filter A replaceable element type fuel strainer and fuel filter (Figs. 1 and 3) are used in the fuel system to remove impurities from the fuel.
The strainer removes the larger foreign particles and the filter removes the small foreign particles. The fuel strainer and fuel filter are basically identical in construction, both consisting of a cover, shell and replaceable element. Since the fuel strainer is placed between the fuel supply tank and the fuel pump, it functions under suction; the fuel filter, which is installed between the fuel pump and the fuel inlet manifold in the cylinder head, operates under pressure. Fig. 4 - Typical Spin-On Fuel Filter Mounting Spin-On Type Fuel Filtea Replace the elements as follows: A spin-on type fuel strainer and fuel filter (Fig. 4) is used on certain engines.
The spin-on filter cartridge consists of a shell, element and gasket combined into a unitized replacement assembly. No separate springs or seats are required to support the filters. 1. With the engine shut down. place a suitable container under the fuel strainer or filter and open the drain cock. The fuel will drain more freely if the cover nut is loosened slightly. The filter covers incorporate a threaded sleeve to accept the spin-on filter cartridges. The word “Primary” is cast on the fuel strainer cover and the word “Secondary” is cast on the fuel filter cover for identification. 2. Support the shell, unscrew the cover nut and remove the shell and element. 3.
Remove and discard the element and gasket. Clean the shell with fuel oil and dry it with compressed air. No drain cocks are provided on the spin-on filters. Where water is a problem, it is recommended that a water separator be installed. Otherwise, residue may be drained by removing and inverting the filter. Refill the filter with clean fuel oil before reinstalling it. 4. Place a new element, which has been thoroughly soaked in clean fuel oil, over the stud and push it down on the seat. Close the drain cock and fill the shell approximately two-thirds full with clean fuel oil. 5.
Affix a new shell gasket, place the shell and element into position under the cover and start the cover nut on the shell stud. A 1 ” diameter twelve-point nut on the bottom of the filter is provided to facilitate removal and installation. 6. Tighten the cover nut only enough to prevent fuel leakage. Replace the filter as follows: 1. Unscrew the filter (or strainer) and discard it. 7. Remove the plug in the strainer or filter cover and fill the shell with fuel. Fuel system primer J 5956 may be used to prime the fuel system. 2. Fill a new filter replacement cartridge about two- thirds full with clean fuel oil. Coat the seal gasket lightly with clean fuel oil. 8.
Start and operate the engine and check the fuel system for leaks. 3. Install the new filter assembly and tighten it to two- thirds of a turn beyond gasket contact. Page 15