Fuel filter change

[Mmiller412]

How do I change the fuel filter on the 250 motor? I’ve located the filter house omg just inside the drivers fender well. But how does to come off? Also, it there a priming limo for this engine? I can’t find any info on any of this stuff

 

[Ajax MD]

You don't say if you have the M809 or M939 series truck, but all the 5-ton tech manuals are located here:

5-ton and up TMs

M54, M817, M123A1C, etc... the big boys! Find TM's related to the 5 ton and larger series trucks in this forum. - No posting of threads

www.steelsoldiers.com

The whole filter housing itself simply unscrews if I remember correctly. If it's been on there forever, you might need a big rubber strap wrench to bust it free.
Obviously, drain the housing with the petcock at the bottom, first.

Fill the filter and housing before installing it. Yes, it's tricky to juggle it, just be careful. To prime the system, use the cold start hand pump on the dash. Also, just above the fuel filter, near the intake hose is a air bleed valve. Open the valve and have Soldier B operate the hand pump in the cab.

When fuel squirts out of the bleed valve, you're done. Try to start the truck.

 

[Mmiller412]

the hand pump on the dash? Do you mean that little button to the left of the steering wheel? Also, when I turn that petcock, nothing drains out. There’s a primer handle just above and forward of the fuel filter. Not sure how to use it cause it doesn’t move in or out.

 

[Ajax MD]

If you've opened the petcock at the bottom of the housing and nothing drains out, you have a lot of crud at the bottom. Open the petcock, grab a piece of stiff wire and stab/swirl around up in there to try to clear it.

I have an M813 truck. I have a hand pump on the dash as part of the "cold start" system. It is also used to prime the system after replacing the filter. I assumed an M923 with 250 would be the same, but I may be wrong. The primer handle may be locked. Push and twist it 90 degrees. Then, it should move in and out...unless it's corroded and stuck.

 

[Ajax MD]

So, after consulting the manuals the 939's with NHC 250 trucks do use an ether cold-start system (the button you mentioned).
The 939 manuals still show the fuel canister and petcock, so I was correct on that count. Open the valve and ream it out with a bit of stiff wire. Use a rubber strap wrench to unscrew the housing if necessary.

The operator's manual contains the fuel system priming procedure and yes, it looks like the priming pump is in the engine compartment, not in the cab as with the M809's. Here's the link to the operator's manual:

https://www.steelsoldiers.com/attachments/tm9-2320-272-10-july-2012-pdf.462278/

 

[Mmiller412]

So, after consulting the manuals the 939's with NHC 250 trucks do use an ether cold-start system (the button you mentioned).
The 939 manuals still show the fuel canister and petcock, so I was correct on that count. Open the valve and ream it out with a bit of stiff wire. Use a rubber strap wrench to unscrew the housing if necessary.

The operator's manual contains the fuel system priming procedure and yes, it looks like the priming pump is in the engine compartment, not in the cab as with the M809's. Here's the link to the operator's manual:

https://www.steelsoldiers.com/attachments/tm9-2320-272-10-july-2012-pdf.462278/

Thank you. I appreciate it. Like I said, I'm new to these trucks. And new to this forum. Was having trouble navigating the site to find info. Again, thanks for the help

 

[simp5782]

Thank you. I appreciate it. Like I said, I'm new to these trucks. And new to this forum. Was having trouble navigating the site to find info. Again, thanks for the help

There is a 3/4" head bolt on the top of it. Remove it as it holds the canister on. That bolt has an O ring on it that needs to be replaced as it is in the filter gasket kit as well.

 

[Mmiller412]

There is a 3/4" head bolt on the top of it. Remove it as it holds the canister on. That bolt has an O ring on it that needs to be replaced as it is in the filter gasket kit as well.

Thank you. I figured it was that bolt as the filter housing does not spin off.

 

[Ajax MD]

There is a 3/4" head bolt on the top of it. Remove it as it holds the canister on. That bolt has an O ring on it that needs to be replaced as it is in the filter gasket kit as well.

Ah! That's right! Dang, it's been a year so I haven't messed with mine since that first time. I completely forgot.

 

[77 AMG]

You can also leave the air built up in the tanks, change the filter (filling the canister up, of course) and use a modified fuel cap that has an air chuck on it, and a hose to "pressurize" the tank, open the bleeder and go from there... Thanks for the help on that, Matt.