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Help, I got a fuel leak!

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16 years 10 months ago #12366 by Ol George
First, I would like to thank everyone who gave me some great ideas on how to get my blade to roll forward. I got it done and now to the next 'situation'...
On my Cat 12 grader (S/N 71D438) the #6 fuel injection pump leaks around the base. Sometimes it leaks more than other times; but it still leaks. From the parts catalog, there doesn't appear to be a gasket and to remove the injector seems like a task I'm not sure I want to endure.
Any ideas or techniques on how to fix this problem relatively easy?
The diagram shows the row of fuel injectors, the last one to the right leaks.
Thanks....

Oh yea, I hope fixing this is not as difficult as posting the attached thumbnail! Whew, now that was a chore!
Attachments:

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16 years 10 months ago #12369 by ccjersey
Replied by ccjersey on topic Help, I got a fuel leak!
George,
the seal is 2a3307 on each pump shown top right of the scan you posted. The pumps aren't a lot of trouble to remove, just clean it all really well, remove the line and then open up the side cover so you can keep the plunger in as you remove the pump from the top. Keep the plunger in to keep it clean and prevent any dings etc. Replace the seal and put it back in. There is a dot on the rack and on the gear sector of the plunger that have to be timed up when you put it back in. You look in the side as you put it back to time it up.

Sure you don't have one of the pump housings with the individual bleeds behind each pump. Those sometimes will shake loose and leak, but usually really obvious and leaking a lot.

D2-5J's, D6-9U's, D318 and D333 power units, 12E-99E grader, 922B & 944A wheel loaders, D330C generator set, DW20 water tanker and a bunch of Jersey cows to take care of in my spare time:D

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16 years 10 months ago #12370 by Old Magnet
Replied by Old Magnet on topic Help, I got a fuel leak!
The seal you need to replace is a #2A3307, shown in the view of the separate injector pump up and to the right in the parts diagram.
Your right there is no gasket.
Not a big job to remove the pump and replace the seal. If your just doing one you can probably get by without air bleeding the system but if you do them all you will have to go through the bleeding ritual.

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16 years 10 months ago #12373 by Ol George
Replied by Ol George on topic Good info. I'll try it.
OKAY! Man this bulletin board is great!... I guess I'll have to gear-up and fix it.
From what ccjersey tells me it is the same as the book explains. But...
Does the plunger run horizontally or is it vertical, and where do I 'mark it'; is the gear on the plunger, and the 'rack' on the pump? Do I just line-up the dots? (I guess basically, I'm putting the thing back in the same way it came out. Right?) Also, is the seal a 'rubber-like' material? (Of course it is - Probably) :o
Any other tips or explanation is very helpful.
I'll order the parts and... let you know how it turns out.
Thanks.

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16 years 10 months ago #12374 by SJ
Replied by SJ on topic Fuel Leak
I,ll jump in & answer, the plungers move up & down vertically & the wheel (gear) on the bottom of the plunger has teeth machined in it & they are turned by the rack bar which is a bar of steel with teeth on it that moves horizonally and controlled by the governer.These gears on the bottom of the plunger has a mark or dot on the one gear tooth and the rack bar has a mark in between two teeth and you line these marks up, the one on the plunger gear to the one on the rack bar.To see it easier it,s best to take the side cover off the area below the pumps on the side of the housing.It will be clear what I,m saying when you get into it.If more than one pump & plunger is removed you always keep them paired up so never mix one plunger with another pump body asthey are fit to each other at the factory. Another thing if the pump gear is not timed to the rack bar correctly you will have a miss or erratic running engine on that cylinder.

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16 years 10 months ago #12377 by carlsharp
Replied by carlsharp on topic Help, I got a fuel leak!
Not to circumvent the valued professionals here, but mine was leaking, too. I took the pump off, cleaned the seal and surfaces, put a VERY light coat of silicone on the seal and reassembled. Not a drop since.
Don't worry about the rack/gear it's very obvious how it goes, and you have the other 5 to set an example. Just use the throttle to center the rack on the gears before disassembly. I dunno how close you are, but I have the bleeder tool if you need to borrow it, those things can be a bear to get a wrench on! I also lubed the rack/guides/gears/ with some light grease while I was in there.

CS

Carl Sharp
Chino, CA
2xPV15; 22 2F; D4 5T
Various other oddball stuff
Vids: www.youtube.com/profile?user=carl4043

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16 years 10 months ago #12391 by Ol George
Replied by Ol George on topic Help, I got a fuel leak!
I think I'm getti'n the picture now; with the assistance of you guys and the manual, I just gotta get in there and do it! I am much more confident than before. Although I'm relatively 'mechanical' I like to know what I'm getting into before I jump in.
As far as the bleeding ritual; I've done it before. My technique is probably primitive as I just set some buckets under the engine, pump like crazy as I turn each bleeder valve. I took a small wrench and bent it at a 90 degrees to allow accesss. I didn't know there was a bleeder tool. Hopefully I won't need to bleed it; it costs me about 4-5 gallons of diesel. Maybe I should connect tubes to each bleeder valve and let them run into a clean bucket? By the way, Carlsharp, thankks for the offer. I'm in Southern Ca. outside of the Palm Springs area if your close enough to loan me the bleeder tool. If not, I think I'll be alright.
At any rate, I think I'm ready.... Thanks again to all and we'll see how it goes. Yea, I'll let ya know.

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16 years 10 months ago #12397 by SJ
Replied by SJ on topic Bleeding
You can just pull the throttle part way on and just open each fuel line on top the pumps and you can bleed it that way.Later pumps did away with the bleeder screws behind the lines on the pumps.

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16 years 10 months ago #12504 by Ol George
Replied by Ol George on topic Help, I got a fuel leak!
Thanks SJ but I'm not sure what you mean. This grader has a small valve just behind the cap/fuel line of the pump. I think it might be easier for me to open this valve as I pump (like crazy) the plunger located near the filter housing. It takes awhile but I can tell when all of the air is out. Then all I gotta' do is start er' up... as long as I haven't drained my batteries from trying to start it with air in the lines. I feel comfortable doing it this way and the manuel explains it that way as well. Not sure but is sounds like the way you describe, the engine needs to be running.

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16 years 10 months ago #12508 by SJ
Replied by SJ on topic Bleeding
The screws I,m talking about is on each injection pump and that,s the ones you can bleed if you don,t have the wrench for the round screw with two flat spots on it.The filter housing has two bleeder screws to open up and the one for the filter base is also a round screw with two flat spots and it gets bled first to make sure the filter base is full and all the air is bled off. The second one is on the top cover of the filter base and it has a wheel type handle to turn it to bleed the air off in the top of the base before fuel goes to the injection housing & pumps themselves.What I always did at the dealer shop was fill the filter base nearly full with good clean fuel before I dropped the new filter elements down in & then put the cover on. The fuel has to go through the filters to be filtered anyway before going up through the top of housing and into the injection pump base but clean fuel is a plus.

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