Unable to tighten injection pump shaft nut to specs

[Supa]

Went through the process of replacing my CP3 pump and all went well except I can't get the pump shaft nut to tighten to 77 ft/lbs of torque per spec. I got it maybe to around 40 ft/lbs and then it turns the flywheel/fan/etc if I turn it either direction! The factory manual and all the online writeups/videos I found don't talk about how to keep the flywheel from turning. Any quick suggestions that hopefully don't involve having to buy a special tool?

Much thanks in advance!

2004.5 Ram 2500 5.9 4x4 Auto...

 

[Supa]

Well we figured it out... had my friend put a wrench on the pulley below the fan to brace it... now the REAL problem is that the new/remanufactured pump leaks! They didn't include a new O-Ring so I reused the one on the old pump... do you think that could have caused it? The old pump did not leak...

Anything y'all can think of that I may have missed? Seems like fuel is coming from the mating surface where the pump attaches to the mounting flange.

 

[dieselshadow]

O-rings can absolutely cause leaks, especially old used ones. Never reuse an old o-ring in critical applications such as this. A $.25 o-ring can cause you to have to do the job all over again. O-rings are cheap, but your time is expensive and doing a job all over again is more time, money, and frustration.

 

[Timd32]

Engine Barring Tool they can be had for about $20 off ebay, or like $40 from Genos. Good tool to have in your box.

There is a plug on the bell housing on the passenger side for mine pops right out, put in the tool.

I realize you posted at 10pm and were in a bind. Good luck on your repair.

https://www.genosgarage.com/product/tool-ltbt/tools

 

[dieselshadow]

That barring tool also locks up the engine for the most part if you're working on things like that pump nut. It’s a very handy tool to have.

 

[jghflys]

Well we figured it out... had my friend put a wrench on the pulley below the fan to brace it... now the REAL problem is that the new/remanufactured pump leaks! They didn't include a new O-Ring so I reused the one on the old pump... do you think that could have caused it? The old pump did not leak...

Anything y'all can think of that I may have missed? Seems like fuel is coming from the mating surface where the pump attaches to the mounting flange.

There is a weep hole in the CP3 pump to prevent diesel getting into the engine oil if the high pressure seal leaks. Here is a picture. If you are leaking fuel from the pump it is defective. If the o-ring leaks it will leak engine oil. My son and I both used Bosch remans when we replaced ours. Also make sure that it is not one of the low pressure connections leaking, use new sealing washers.

 

[Supa]

I REALLY appreciate everyone chiming in! So the strange thing I forgot to mention as well, is with the new CP3 pump the truck won't start. We have a FASS Titanium system and the leak starts with the engine in ACC mode and pump running.

So here's the question: the local dealer doesn't have the o-ring. Do I try and find a non-Cummins one at Ace Hardware or continue to use the one?

jghflys - you said if that o-ring leaks we'd actually see engine oil and not fuel? So maybe the o-ring is not the problem...

At this point I think we're going to put the old pump back so at least we can have the truck running again (sigh). Doing the job 3 times in two days feels like two sucker-punches to the gut. In a way it feels good to be able to get better/faster at the process... but losing nuts and getting dinged up is getting old.

 

[jghflys]

I REALLY appreciate everyone chiming in! So the strange thing I forgot to mention as well, is with the new CP3 pump the truck won't start. We have a FASS Titanium system and the leak starts with the engine in ACC mode and pump running.

So here's the question: the local dealer doesn't have the o-ring. Do I try and find a non-Cummins one at Ace Hardware or continue to use the one?

jghflys - you said if that o-ring leaks we'd actually see engine oil and not fuel? So maybe the o-ring is not the problem...

At this point I think we're going to put the old pump back so at least we can have the truck running again (sigh). Doing the job 3 times in two days feels like two sucker-punches to the gut. In a way it feels good to be able to get better/faster at the process... but losing nuts and getting dinged up is getting old.

If the leak is not from the connection to to the pump from the FASS system, the pump is defective and has an internal seal leak. The oring on the nose of the CP3 pump seals against engine oil and seals the weep hole from the engine. The weep hole is on the upper side of the pump nose. When you remove the "new" pump turn it over ans see if diesel comes out of the weep hole. If it does you have verified the pump seal is leaking. If it does not, the pump may still be bad, but there no vent path to allow the fuel to come out of the weep hole. The Cummins oring number is 3949688.

 

[sag2]

If it leaks from just the lift pump, hook up the inlet without installing the pump and see where it's leaking from.

 

[Supa]

It was leaking in two places in the seam of the injection pump... we put our old pump back and no leak. Based on all of your input and reinstalling the reman pump two times... it definitely seems like a defective pump. Anyway, returning it and coming up with a new game plan.

We appreciate everyone's input, you guys are awesome!