Dump Truck Running Poorly

[sandcobra164]

I helped another member recover a M817 out of Albany. The truck made it to my house (15 Miles) but is running poorly. It will only run at full throttle and if you let the clutch out too quickly and bring the rpm's down, it will stall. It is hard to crank without ether as well. Please steer me in the right direction, this truck needs to go about 350 more miles to it's owner's home and he wants to drive it. I told him that I'd take a look at it but I'm new to the 5 tons. Please give some suggestions as to what I need to check so that we can have a more successful recovery effort.

 

[Ferroequinologist]

Fuel filter changed? if it is blocked it would cause hard starting and starvation issues at lower throttle settings. Also, I would check the fuel line for air leaks, especially the tank valve under the cab. There are a couple of rubber hoses that like to crack and split on that valve. Air getting into the fuel line could allow the engine to run if it is pulling the fuel through fast enough to overcome the air leak.

5 tons don't have in tank pumps.

 

[Floridianson]

I just went through this on mine . Take off step and tool box. Use razor knife cut off all rubber lines. For now just get 2 feet of fuel line both sizes. connect just to one tank and see how she runs. I would not run the fuel as is . I added 30 gal. of fresh stuff and the fuel additive before I ran the motor. I changed the oil in the motor before started to. Mine running much better now but a little sluggish on the pickup. Here I am going to have the pump rebuilt. Also when the valve is off the truck I will put pressure on the valve under water and check it out to.

 

[BKubu]

Driving a truck home 350 miles that has been in storage and sitting for a long time is asking for trouble. I agree with the previous two posters. Change the fuel filter, oil and oil fiter...add fresh fuel and conditioner...check for air leaks in the fuel lines...make sure there is an air filter in the cannister (I've seen them get removed and not replaced) and make sure a rodent or bees have not made a nest in the cannister.

 

[kipman]

You can call me at 614-440-9039, worked on many 5 tons, I am on my way now to get 3 dumps running that have sat for 10 years, Kip Thompson.

 

[sandcobra164]

The owner did bypass the tank selector valve and just has the driver's side tank connected to the fuel filter inlet. Can anyone provide a good Napa part # for the fuel filter? I'll be able to look at the truck a little more this afternoon and will try the simple stuff like draining the fuel filter, checking the intake tract, etc. Thanks for the input.

 

[CGarbee]

I drove a M817 from OH to NC after a GL purchase a few years back. Had a buddy (AMGeneral) behind me in a M816 for the trip...

We did the filter and fluid swap, changed out the fuel line from the filter to the pump, and straightlined around the selector switch. Truck still ran just as you describe this one (good think it was bassically all intersate driving where I could keep the throttle pushed way down... ). Ended up having to have the injector pump rebuilt as it was worn out.

If you do a search on this site, you'll find more than one thread such as this one with the filter and belt numbers in it.
http://www.steelsoldiers.com/5-ton-up/42936-filter-part-s.html

Meanwhile, to make your life easier:

Oil: Wix 51954 or NAPA 1954, Lubrifiner LF516
Fuel: Kaydon C220086 or Wix 33401 or NAPA 3401, Lubrifiner FS1201

I get my filters from either the local Komatsu dealer (they like Lubrifiner numbers) or CarQuest (they like the Wix numbers). Both are located about five blocks from my office...

Good luck.

 

[jwaller]

napa fuel filter 3401
wix fuel 33401.

neither are cheap but most all of them stock it. I'd refill the filter with fuel too before reinstall.

 

[sandcobra164]

I drained the fuel filter (lots of water). Now I can't get the system to prime. I don't think the primer on the dash works. I took it apart and lubed the inside of it but had no luck even after about 10 minutes of pumping. I'm considering capping the fitting that currently has the plastic line run to it and see if I can prime the system by cracking open an injector while cranking. Any thought's on the priming system?

 

[CGarbee]

It takes "forever" to prime using the dash pump... I fill the filter before I put it on, and it still takes a bit of effort.

If you have a handy source of compressed air, pressurize the tank (gently) by removing the vent line and using its fitting (just push the tip of your blowgun onto it). You'll push the fuel up to the pump that way... Have a buddy work the air while you hit the starter and you don't even have to crack a line...


If you drained a lot of water out of the filter, you should go ahead and change it. You likely have enough stuff growing in the filter to be reducing the flow a lot. You should also ensure that you don't have sufficient water in the tank that you are just pumping water instead of fuel into the system...

 

[pctrans]

Another suggestion, when you change the fuel filter, fill the canister with diesel injector cleaner. That will give it a good dose on startup. I do the same on my over-the-road truck. Works good.

 

[sandcobra164]

I plugged the fitting leading to the primer assembly. Now the truck starts, revs and idles decently. Now onto the fun task of replacing tank switch hoses. Currently the tank switch is bypassed but it still sprays fuel from the outlet side of the valve. What is pressuring the fuel and causing the fuel to come out? Possibly the valve itself is defective? It should only be connected to the passenger side tank at this point but it gives a good spray especially when you rev it up.

 

[sandcobra164]

The TM searching seemed to answer my last question. The fuel that's coming out must be return fuel and it's coming right out since the lines aren't hooked to the tank select valve. Makes me start to question whether it was sucking in air at that valve since I fixed the air leak that was causing the truck to run poorly. I'll probably try to connect the hoses back the correct way and see how the truck runs. More to follow tomorrow. Keep those suggestions coming.

Thanks,

Joseph

 

[doghead]

The selector valve diverts the fuel return to the tank that is selected. Perhaps you are seeing the return fuel coming out.

 

[Floridianson]

If you truck is like mine with barb fittings use no hose clamps.

 

[sandcobra164]

Hooked up the fuel lines to the filter and driver's side tank, gave her a sniff of ether and she's back up and running again. I don't see any leaks from the tank selector valve or anywhere else so the truck should be good to go. If it were my truck, I'd still probably replace the rubber hoses as a precaution but she's off to Alabama this weekend to go play at her new home. Makes me kind of want a 5 ton now!!! Seems to be a simple enough motor and the power steering is nice. Now to air up a tire and see how it drives down the road.

 

[BEASTMASTER]

did you check for kritter nests in the air cleaner?? will keep her from taching out to max.

 

[sandcobra164]

10-4, air cleaner looked fairly new and the canister was clean. I drove the truck this afternoon and it ran pretty good. I kept it really slow on just my dirt road as the truck seems to have a leaking wheel cylinder. It has nearly no brakes until just at the bottom of the pedal travel. They will pump up and the master cylinder was full when I left. More things to check tomorrow. I plan on just keeping the master cylinder filled and just keep pumping the brakes so I can find the offending wheel cylinder.

 

[sandcobra164]

Offending wheel cylinder looks to be the passenger front. I'd like to give this truck back in road running condition so the new owner can make his recovery. How much work, what part number's, etc are needed. Do any parts stores have the wheel cylinder's for the front axle of the 5 tons? I know I should search but it's late, it's not even my truck but I'm worried this guy may try to drive it home as is and I'd feel much better if it left with good brakes. Thanks. I guess I could disappear and leave a chain and lock on the steering wheel but that doesn't seem right!!!!!!!!!

 

[sandcobra164]

Made a little progress on the dump today. After a little PMCS, a lot of grease and some hydraulic oil, we have a functioning dump bed!!!!!!!!! Next will be the leaking wheel cylinder when it comes in!!!!!!!!