JD855 Fuel Priming

[WIJohnDeere855]

Can anyone tell me if the fuel lines on a JD 855 are self priming? I ordered a sevice manual and it hasnt gotten here yet!!! I searched the forum but couldn't find anything on the 855 and how to prime it. I had to repalce a fuel line and dont want to wait until the manual get here.

 

[beenthere]

WI JD
Here is a clip from the shop manual

 

[Mechanos]

From the service manual: All 955 Tractors and late model 855 Tractors (S/N
615001?99,999 and 1990 models S/N 10,001 ) use a mechanical fuel pump.

That's a beef of mine. In the repair section (above) it tells of some models using a mechanical fuel pump... however it only cover the bleed procedure for the electrical fuel pump models.

 

[JD755]

Need to determine if you have a late or early model 855. If the battery is in front of the radiator and the fuel tank is behind the instrument panel you have a late model. If the fuel tank is in front of the radiator and the battery is behind the instrument panel you have an early model. These changes coincided with the introduction of the 955 which required a larger capacity tank.

The early model used an electric fuel pump so the procedure shown by beenthere will work for you. Those first two bleed points receive fuel pressure from the electric pump. The third one, at the injection pump, requires the engine to be turning so you need to use Start to crank it. Bleeding at the injection pump is only required if the engine will not run smoothly after doing the first two points.

The later model has a mechanical pump so the engine needs to be cranking for all bleed points. The maintenance manual does not describe this, but the late model operator manual does.

 

[WIJohnDeere855]

Thanks again to everyone. JD755 you have been very helpful. Mine is a 1993 with the tank just in front of the panel and your manual page is exactly how my fuel filter looks. Thanks again for the help hope that manual gets here soon, so I dont need to keep bothering everyone.

 

[dfkrug]

That's a beef of mine. In the repair section (above) it tells of some models using a mechanical fuel pump... however it only cover the bleed procedure for the electrical fuel pump models.

I agree. My 1996-model 955s all had the mechanical pump.

If I may add one thing about my experiences bleeding the mechanical
system: There is a hand lever on the pump that allows you to operate
the pump manually to bleed the air out. You start with the first screw on
the fuel bowl, then the one on the injector pump. You pump the lever
until you get fuel with no bubbles out of the bleeders. Then you start
the engine. I never had to crack open the injector nuts.

Bleeding is easy if you follow those steps.

 

[WIJohnDeere855]

Got it primed on the first try. I have have had a number of diesels and some are a little tricky but this on was a piece of cake. Thanks again for all the input.

 

[JD755]

Got it primed on the first try. I have have had a number of diesels and some are a little tricky but this on was a piece of cake. Thanks again for all the input.

Glad to hear it. I agree it is very easy. I have never had to go beyond the second bleed point. After the second one it will start and immediately run smoothly, even the time it ran dry after a fuel line to the filter came loose.

 

[dsmau]

Past experience on my later model 855:
Before the fuel line in my tank was fixed, I ran out of fuel in the middle of the field. I put fuel back in the tank and did not do anything else. It cranked maybe 10 seconds then started and ran perfect. Did I take a chance of breaking something? Tractor has been working well since.

 

[dfkrug]

It cranked maybe 10 seconds then started and ran perfect. Did I take a chance of breaking something?

No, you did not hurt anything. Your FI pump and fuel pump was able to
pump the air out. It does not always work that way. Sometimes you
have to crank a LONG time, or the engine starts and dies multiple times
until the air is pumped out.

Note that the newest CUTs have apparently eliminated the need to bleed
air anymore. At least all the ones I have seen.