HOSE AS 3599709 - Caterpillar

Fuel Connections
A common reason for service problems with fuel systems is the use of poor or incompatible connectors, where the pressure tightness depends upon the use of sealing compounds, hose clamps, fibre washers trapped between inadequate and unmachined faces, or compression fittings which have been over-tightened to the point where they no longer seal.Cleanliness during initial assembly is also of vital importance, particularly when fuel tanks are installed, as glass fibres and other rubbish may enter tanks through uncovered apertures.It is strongly recommended that the flexible fuel pipes available as an option with the engine are used, which are as follows: Fuel Feed- all modelsThe free end of the flexible fuel pipe has either:* a 1/4" NPT female thread.or* a1/4" BSP male thread, and is supplied with a nut and olive to suit 5/16" OD steel or copper tube. Fuel Return- all modelsThe free end of the flexible pipe has either:* a 1/4" NPT female thread.or* a 7/16" UNS male thread, and is supplied with a nut and ferrule to suit 1/4" OD steel or copper tube.
Ensure that flexible fuel hose routing avoids coming into contact with parts of the engine which can lead to abrasion of the hose.
Fuel Tanks
Fuel tanks should have the following features:* The filler neck should be raised so that water will not enter when filling.* The filler cap should seal effectively to prevent water entering when under way.* A vent pipe should be fitted, again in such a way as to avoid the entry of water.* The tank should have a sump or angled bottom with a drain tap so that water and sediment can be removed. (This is not always possible).* Internal baffles may be required to prevent fuel surge.* The tank should have a removable panel to simplify cleaning.* The fuel pipework should be as simple as possible with the minimum of valves and cross connections, so that obscure fuel feed problems are minimized.* A fuel sedimenter (water separator) is required in the fuel system between the fuel tank and the engine mounted lift pump. To avoid problems when venting air after draining the sedimenter, it should preferably be installed below the normal minimum level of fuel in the fuel tank. (This is not always possible!).* The tank should have at least two connections; a fuel feed connection, and a fuel return connection. Whenever possible a tank should only supply one engine, but in any case each engine should have its own fuel pipes, from tank to engine.Typical Fuel Systems
The more simple the fuel system, the better it will perform in service. Figure (A) shows an ideal system. In some applications there may be legislation that requires that fuel lines draw from and return to, the top of the tank. Figure (B) shows an acceptable arrangement. The fuel tank may be steel, aluminium, or G.R. P. (Glass Reinforced Plastic) or, alternatively, a rubber bag tank may be used. The main fuel connection is taken from the rear of the tank so