818 sucking air, tried alot

[sandcobra164]

I'm currently working on an M818 that I recovered out of Thomasville, GA. Anyhow, I replaced all the rubber lines to the selector valve and the main rubber line from the filter housing to the IP. It ran great for a little while, idled for once and was somewhat responsive to the throttle. Now it's doing exactly as it was before. I now suspect the primer pump line. It will prime and the pump will get hard to push. It does drop it's pressure on the gauge rather quickly. No big deal, that's the fuel going into the intake from the nozzle from what I've read. However, while running, the primer pump will lose it's "prime" rather quickly and will take about 2 or 3 pumps to build any resistance or pressure on the gauge. It also leaks diesel from time to time while pumping. Are the O-rings simply bad or should I just cap the IP where the primer line comes out. I'll probably go that route since I'm in the South and the trucks owner probably won't need the cold start feature anyhow. I've had trouble from the hard plastic lines leaking in the past and short of a leakdown check on the fuel system, this will probably be my next step. Let me know what you guys think. I'm wanting to get this truck ready to hit the open road.

 

[doghead]

The pump has 2 o rings and it has a pair of check balls with light springs. (hard to push could be a stuck check ball)

The primer pump can be used to fill(fuel) and purge the system of air after a filter change. So it is useful even in warm climates.

 

[sandcobra164]

Hard to push is accompanied by 60 or above on the gauge. It's not bad below that.

 

[EMD567]

Check the 2 "O" rings on the primer pump. If not, then you have a leak in the plastic line.
As far as needing the primer pump, it gets petty **** could in SC.

 

[yamabro]

I agree w/ doghead the primer is very useful. I wouldn't suggest losing it

 

[sandcobra164]

10-4, Where would I find some of this hard plastic line? I've honestly never seen it at any parts stores but it could be in the "back room". I'm sure I can match the O-rings pretty easy at my local Napa. I've got a great part's guy there and that's not an advertisement. It only works in Leesburg with Mr. Trevor. He's likely not at your local store.

 

[dozer1]

Joseph, I JUST came in from the shop and replaced my primer pump o-rings as suggested to me by 73m819. Woke my formerly useless primer pump right up. Took about 15 minutes. They were 012 o-rings in my set.

 

[sandcobra164]

Dean, I'm glad you've worked hard on you M817 and had some great progress on it. Maybe one day I'll own a 5 ton. As for now, I'm still working on these things for other folks. As for the primer being useful, it might be after a filter change if you open the valve by the air intake. For What It's Worth, the primer still primed after I changed all of the rubber lines in the same 2 or 3 strokes so I think it only primes the intake injector and not the rest of the system if used without opening the valve by the air intake. If anyone know's where to get some replacement plastic line, let me know. It's not my truck but another member's truck that hopefully will go another couple of hundred miles up the road. It's got other issues but I'll take those on once it runs like it should. We'll then see about that transfer case that has lost High Range but has Low Range. That'll be another search in the TM's and maybe another post!!! I'm almost to 100 and will soon post in the classifieds (inside forum joke).

 

[timntrucks]

i get mine from truck pro.. its not white its black... and a biggie.. as was told by the counter guy.. you buy the line.(real cheap) and the pherrals.. but you need a special inner brass insert.. its job is to not let the plastic line collapse as your tightening it up.. they are cheap.. 20 cents each im thinking and you only need 4. the orings arent hard to change. you said you changed the fuel filter... did you make sure the square washer was down in the hole before tightening up that top bolt?

 

[bob130ab]

air in sys

I had the same problem, it was the plastic line from the hand pump to the engine pump. I removed the line & put a brass plug in the pump, no more problems.

Bob Martin

 

[FormerNewMVGuy]

A friend of mine wanted to change the plastic lines, So he went with copper lines, I dont know if he finished it yet, But the line and the fittings are readily available from any home improvement center.

And also look at the thread http://www.steelsoldiers.com/5-ton-up/68695-809-series-fuel-issue.html

 

[doghead]

Fittings from the home centers, black line from auto/truck store. Use DOT approved air brake tubing.

 

[73m819]

i get mine from truck pro.. its not white its black... and a biggie.. as was told by the counter guy.. you buy the line.(real cheap) and the pherrals.. but you need a special inner brass insert.. its job is to not let the plastic line collapse as your tightening it up.. they are cheap.. 20 cents each im thinking and you only need 4. the orings arent hard to change. you said you changed the fuel filter... did you make sure the square washer was down in the hole before tightening up that top bolt?

If you did tighten the square washer where it was NOT down in the recess, you BENT it and will not seal if put in the recess and tightened, you have to remove it and FLATEN it so it will seal when reinstalled, ask Tim, he has FIRST hand knowledge with this tid-bit of MV info.