Engine/Transmission (1994 - 1998) Leaking lift pump,, Is it repairable????

[94ram]

My 94 is dripping fuel around the lift pump, It is not a line leaking, but looks like its dripping right out of the bottom of the casting.



Does the pump have a weep hole for when things go bad, /or maybe the housing is cracked?



I read on here that you can take the pump apart and replace O-rings, Could this fix the leak?



The truck still runs with this leak, Of course I don't want to drive it this way though.



Is the LP hard to remove? Any tricks or tips?

Thanks,

KB

 

[Joe G.]

It will probably cost you about 50 cents. The O-ring for the push button is usually the cause of a lift pump leak. The button is made of plastic so be carefull when you remove it. You can do that without having to remove the lift pump. Remove the rubber button cover. Then unscrew the button. If that does not stop the leak there are two more O-rings. One on the input and one on the output.



You can get O-rings at NAPA. Just get the one out of their O-ring box that is closest in size.

 

[94ram]

I believe my leak is coming out real close to the block, I found out their is a weep hole in the pump.

Does this mean replacement is the only option?

OR are their Orings that can be replaced for this also?



thanks, KB

 

[Joe G.]

Look for a leak somewhere above the lift pump. I've never seen a post about a leak at the weep hole. Maybe, but it's gotta be a really rare thing. I had a bad drip from the bottom of the lift pump. It turned out to be the input fitting to the fuel filter. It is a double banjo fitting. The top fitting is from the return line from the injectors. The bottom fitting is from the lift pump. If you have a leak there it will run down the steel line to the lift pump. I replaced both sets of copper washers to fix that one. If the WIF drain leaks it will also drip on the lift pump. If the output fitting of the lift pump leaks it will appear at the bottom of the lift pump.

 

[DieselDoghouse]

I second Joe G. Before replying I went out the the bench and looked at the Carter lift pump (should be same as yours) I pulled last fall. There's no weep port and fuel leaking past the piston would run down the bore into the engine. If you can access a flexible bore scope, see if you can look behind the pump casting, fuel preheater, filter for any leaks. Also the check valves on the Carters screw into the casting and could be leaking on the engine side?…

 

[Lightman]

They do have a weep hole it is small. It is located above the primer bore in the main piston bore close to the mounting flange on the front side of the pump if it is mounted on the engine. It is there so that the fuel will leak externally and not into the crankcase causing lubricity problems. I have personally had one leak from the weep hole with about 220k on the clock. There is a repair kit available through Cummins with all the seals and new checkvalve. I can get the part number but it wont be till monday.

 

[Cooker]

There is a repair kit available through Cummins with all the seals and new checkvalve. I can get the part number but it wont be till monday.

I never knew there was a repair kit for the lift pump for a 12v?

 

[Lightman]

Its listed in the cummins parts book but I cant get it till monday.

 

[Missouri Mule]

I have read about a rebuild kit for the lift pump several years ago.

 

[Cooker]

I was surprised to read about a rebuild kit so I did a little TDR searching. It looks like there may possibly be one available but I could not find evidence of anybody who has actually sourced one.

Cummins Service Literature (shop manual/troubleshooting manuals) list such a repair kit, but I've yet to find a Cummins distributor that can find any/ get any parts to rebuild the lift pump. The manuals seem to indicate that check valves and seals were included in the kit. The other possible wear items are the springs and the plunger that rides on the cam.



Good luck

Andy

 

[Lightman]

The cummins part number for the rebuild kit is 3926764.

 

[Matthug]

I picked up my lift pump off ebay brand new for $80, gaskets at the cummins dealer were decently pricy I think 5 bucks a piece (need 2) but you need those if you were rebuilding your pump too. Mine puts out 25 PSI at idle and 34 PSI at 2000 RPM.

 

[tp0d]

The cummins part number for the rebuild kit is 3926764.

Is this an on-engine rebuild or off?



any idea of cost?



Thanks



-j

 

[Lightman]

To complete the rebuild properly it should be removed from the truck.

 

[Vaughn MacKenzie]

The cummins part number for the rebuild kit is 3926764.

Cummins NW says that PN comes up as an engine block heater.



If I go online and look at this document http://www.cumminsfirepower.com/images/legacy/parts_catalogs/6cfparts.pdf

it says that PN is a lift pump service kit, for the C-series (8. 3L) engine.

 

[Missouri Mule]

I believe that the repair/rebuild kit was mentioned in a issue of the TDR magizine along with the part number but I don't remember which one.

 

[JFaughn]

I'm looking at maybe needing a lift pump , so my search brought me to this point [ the theard being a few months old and not finished yet ], so I thought I'ld bring it back , to get more info ,
whitch issue of TDR ? , or a better part # .

 

[fr8train]

Lift pump kit?

I just bought a lift pump from e-bay for my 5. 9. It is pictured on e-bay & says it is for 8. 3. I'm told the only difference is the out-put pressure. The 8. 3 puts out 5psi more press. Not a problem, because our high press. pump controls pressure & returns excess to tank.