To Fill or Not To Fill

[RHARVEY]

I am getting ready to do the fuel filter myself for the first time. This is the element type that goes into the steel canister and the truck has hydro vac brakes.

When I change the filter do I re-fill the canister or do I use the prime pump to refill the canister. If I use the prime pump how many pumps to refill it. .



Thanks

Rick

 

[bowhunter]

I believe its a 10 mm bolt on top of the fuel canister, next to the nut that holds the canister bowl--this is your bleed bolt. After you take the old filter out with old o-rings, install the new, and tighten everthing back up--you will loosen the brass bleed bolt a few turns pump the canister back up with the hand primer pump. Keep pumping the plunger pump until you hear fuel squirting through the injectors. Then tighten the brass bolt. You will hear a hissing sound.



This takes a little while, but you will never, even for a split second allow your injector pump to run without fuel, or to grap a gasp of air.



I do this with every filter change and the truck never cranks when you go to restart it. It starts as if you have just shut it off.



Kurt

 

[QRTRHRS]

I prefill mine first because it seems to take a lot of awkward pumping otherwise. The filter soaks up a lot of fuel too, similar to prefilling the oil filter. I stop at about 3/4 full. I take the plastic bag the filter was in and put the filter/cannister in that. I then crawl under and set it up on the frame. Returning to the top, I mount it. I have not taken a major bath with fuel doing this either. The bag will catch the fuel if I fumble and keep dirt out.



Course', I continue as said with the pumping and bleeding to finish it.

 

[Joe G.]

Rick,



If you pre-fill that fuel is not filtered. If you fill it with the push button all the fuel is filtered.

 

[RHARVEY]

Bowhunter,



I have the fleetguard filter(kit). . with all the rubber gaskets. Is there a gasket that goes on the bottom of the filter 'hood' or does it seal around the filter. There is a gasket that is square in shape(also its round of course). . or is there one that I need to get to replace the one where the canister mates up with the filter hood?

Sorry about all the questions but I want to make sure that I have all the parts on hand when I break the seal on the fuel system. I have heard some real horror storys of getting air into the system. . I know,,I know after its all over I will feel real stupid that I didn't do it before. .

Someone always said that the dumb question is the one that you dont ask. .



Thanks

Rick

 

[QRTRHRS]

Originally posted by Joe G.

Rick,



If you pre-fill that fuel is not filtered. If you fill it with the push button all the fuel is filtered.

Mine is, it's coming out of my aux tank for my tractors. Red too!

 

[Deezul1]

I just changed mine for the 1st time since I bought it and did it all from the top. Open the water drain with a bucket under it and it drains all the fuel out which saves messes. I installed mine down through all the crap that was in the way and set it on something , cant remember what but it stayed there while I filled the filter almost full with a funnel and then got the bolt started a little and primed it with the manual lift pump button till over flow, finished tightening and pushed the button (lift pump) a few more times and it started right up and no crawling underneath.

 

[bowhunter]

RHarvey-



I usually change mine every 10, 000 to 15,000 miles--just because there is a lot of people in my area that have gotten bad fuel, including myself. I know that it probably isn't necessary but I have seen 5 guys ruin injector pumps (p7100's) by never changing the pre-filter or the fuel filter and by then getting bad fuel. Gateway Cummins in St. Louis diagnosed this bad fuel problem, they said the inside of the injectors pumps where ate up. ????? Who knows what caused that. The gas station refuses responsibility. Anyway, its cheap insurance if you keep it changed regularly. I now go to only truck stops where there is a lot of fuel that is pumped every day. And I occasionally run a tank of offroad through to lube things up.



I have always used the filter kit from Napa or Autozone, $28. 00 to $29. 00. It comes with (3) O-rings, one that is a square O-ring that mates the new filter cartridge to the filter housing, and one small O-ring that slips on to the top plastic lip of the filter cartridge, and another O-ring that slips over the nipple that you find when you drop the canister out. When it comes apart you will be surprised at how easy it is to see what you have to replace.



You are right there really isn't a stupid question! Good luck! You will probably get a little better fuel mileage after the change, if you have never changed your filter before.



Kurt

 

[RHARVEY]

Bowhunter,

There is 2 lines that are on top of the hood and no other fittings. . which one is the bleed valve??? Is it on top of the banjo fitting of the line that goes to the injector pump or the one that comes from the lift pump????

Again I want to get this straight in my mind so that I have no questions...



Thanks

Rick

 

[RichR]

Rick,

I'm going on memory.

Only one of the two lines has a small 10mm screw in it. Just loosen after putting on the filter. I put it on empty to cut down on the mess. Once you get a good flow from pumping the hell out of it tighten,and try starting. Check for leaks. There was a good filter change write up ine TDR. Gave them away when I dumped the Ram.

Good Luck

Rich Rozak

 

[shendren]

not to be a smart *** here... ... but if you first invest in a service manual, you will probably not have to remember much for this procedure. not to say that the service manual is the end all... . it is useless for changing rotors... . but for this procedure, you probably will find it helpful. good luck. scott.



p. s. this board is by far better than the service manual.....

 

[rrl989]

I always fill with the lift pump plunger, I was curious how many times I had to hit that plunger, so last time I counted, it was approx 200 pumps before I heard the squirt and felt a bit more resistance from the plunger. Since the P7100 is lubricated by the engine oil, and not the fuel, I've heard, read much that air in the lines, from a filter change will not hurt the pump. Unlike most other Diesel systems, running out of fuel with our pump is not a death sentence. If air does get trapped in the lines, there is a procedure in the service manual for bleeding the lines due to the fact that air compresses and may have to be manually purged.



When cranking, can air to the P7100 really cause damage ?

Please explain,



RonL

 

[Elk]

I change my filter every 10k but have never changed the prefilter. Where is it located and what is the procedure?

 

[rrl989]

Elk,



It's located on the bottom of the lift pump. Best to get at it from underneath with socket extentions.



RonL

 

[bowhunter]

RHarvey-



Rick is right. The bleed screw sets on top of the banjo fitting that leads to the injector pump. It has a 10 mm head. Be careful not to overtighten... . it has fine threads.



You just need to pump the plunger until you hear the injectors starting to squirt fuel, then tighten the bleed bolt, and your truck will pop right off.

 

[illflem]

RonL, it usually only takes me 40 pumps. I think the reason it took you so many was the position of the cam that drives the pump, it was probably pushing on the lift pump lever not allowing you a full stroke. If the cam ends up in exactly the wrong place you can even get no stroke at all. It's just luck. All this can be cured by just bumping the engine just a bit. I use a long wood dowel (broom handle) to keep my thumb from wearing out and to get in a comfortable position.



Air to the pump won't cause damage in this situation, it could if you had an air leak all the time while running though. Some parts of the 7100 are lubed by fuel alone. What can happen with too much air after a filter change or running out of fuel is the injection pump will air lock, you will then have to crack open a few injectors to bleed air from the pump.



When manually bleeding the filter the sound and resistance you feel when it's time to stop priming is coming from the overflow valve, not the injectors. You would need to pump up to around 10,000 psi to pop open an injector, that would be a pretty good trick with your thumb.

 

[RHARVEY]

Thanks guys,,,this is all great information. I needed some OJT from some of you that have done it before to know what to watch and listen for. As soon as it gets day light here I out to the drive way for my first filter change. .

I have plenty of coffee... anyone want to come and watch??????

I will let you know the outcome. . I may even take some pictures with my digital camera...



Thanks

Rick

 

[JohnE]

Cummins does <b>NOT</b> recommend pre-filling the fuel filter. You do not have clean enough fuel to pre-fill which bypasses the filter and goes directly to your injector pump. A diesel fuel injection system is not as forgiving as your gasoline injection or lubricating oil systems. Pre-filling an oil filter is fine, provided you don't get the foil seal in the works.



My ESPAR blocks access the primer button. I have to lay on the ground and reach up around the starter to prime. PIA to get under truck, but much easier on the hands priming from under there.



The ISB&amp;C folks have it better in this aspect. The fuel system is supposed to re-prime itself after a filter change.



-John

 

[RHARVEY]

Well the filter is changed and truck is running just fine. I took your directions and I think it might have shuddered 2 times but other than that it worked out great.

From start to finish it took about 30 minutes. I used the prime pump and pumped it about 40 times or until the fuel was being pushed out the bleed bolt. After it did that I tightened it down and then pumped it another 6 times until I could hear a change in the way the valve was sounding.

Thanks for all the information and suggestions... I just saved myself $35 that I would have payed someone else to do it.

Thanks again for the help



Rick

 

[rrl989]

Illflem,



Thanks for the update. Actually, until recently I did not realize I had to loosen the Banjo bleed screw. I've always Just primed after a change and truck always just fires up. If I do it with the bleeder, it will probably end up at the 40 pumps. I'll find out next time.



RonL