# Intl 100E Over Pressurizing Fuel Lines??



## Countryboy (Jun 4, 2011)

I have an Intl 100E track loader circa 1978 or 79 with the D239 4 cyl engine. After5 years of great machine began to start cutting out occasionally- I had replaced fuel filters about 40 hours prior so I do not suspect that as issue. I also noticed fuel smell and fuel leaking from engine compartment. 

Pulled the skirts and discovered fuel leaking from a side cover on the Bosch injection pump- one cover bolt was loose and o-ring was squirting out. I removed cover, inspected o-ring, reinstalled and tightened the bolts very well. Upon starting tractor seemed to run well but within 30-45 minutes of use I was smelling fuel again- this time leaking from the braided fuel return line- at least that is what I guess it to be- line manifolds between all of the injectors and then routes through what appears to be a 3-way fitting (assume one direction goes back to fuel tank?) and the other line continues back to the injection pump.

I assumed that I had a bad return fuel line which finally gave away- however when I finally returned to repair today I started machine to raise bucket and while running just a few minutes (line leaking profusely) the injection pump began to "knock/rattle" quite loud- upon raising rpm it quieted. I elevated bucket and then backed machine out to wash for repair work while backing machine started cutting out and I quickly noticed fuel spraying out the side of injection pump. Got it parked and cleaned and discovered that the side cover had sheared one of the two bolts off and was sparying fuel as a result.

I have a manual for the machine but it does not cover fuel system- is this fuel return line supposed to be under considerable pressure? I fear that my suddenly failed hose may have been caused by over-pressurization? The injection pump seems to generate pressure just fine and speed control raises and lowers rpm as I would expect- I guess it is possible that I twisted this bolt during the cover o-ring replacement and it just coincidentally sheared and blew apart. However the rattling injection pump, suddenly leaking braided line, and cover with high pressure fuel spraying out makes me suspect there may be a pressure relief valve/by-pass valve that is stuck or faulty?

Sorry for the huge thread- I am new to this and wanted to provide my due diligence on the front end. Thanks in advance for any help!


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## cyrush (Apr 20, 2010)

O/K not directly familiar with your application (100E Crawler loader) but am very familiar with the Bosch fuel system.

My engines data base shows the fuel pump to be a EP/VA4 --------------- CR type. this is a 4 cyl rotary pump with hydraulic governor.

Your fuel system may incorporate a fuel supply pump between tank and filters/injection pump (or it may Not )

INside the injector pump is a transfer [ump which raises the fuel pressure inside the pump casing to allow this raised pressure to act in the hydraulic governor (Inside pump) to control engine speed . This higher pressure fluid inside the pump also lubricates the internal workings of the pump, and cools it.

If there was no circulation of fuel from tank to pump, to tank then the pump would get very hot. 

Where the return line cones out of the pump the fitting should contain a small orifice, this controls the pumps internal case pressure, but if blocked it can cause excess pressure and leaks. This return line then joins with the leak off line from the injectors and goes back to the tank.Tthe fitting where the return line enters the tank may also contain a small check valve to maintain a positive pressure in the line and prevent drain down. Some times the check valve will jam closed causing leaks as in your braided return hose

Leaks from the main pump body can cause transfer pressure inside the pump to drop and as a result the engine rpm may become unstable (surging) or the engine may periodically stop.


Do you have an engine and fuel systems manual for your machine. if not i can supply them on a CD rom, drop me a PM


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## garysphone28 (4 mo ago)

I know this is very old, im looking for service manual for 100 e series track loader if anyone can help email me plz. [email protected] tia


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