I reshaped my Bully Dog pin to a more aggressive profile. The power is nice, however, there's a leak coming from the weep hole. So if I R&R the o-ring, do I need to put in a longer fuel pin (i.e. roller bearing, drill bit, etc.) or will I be good to go with just a new o-ring? Any thoughts on this?

 

Yes, to replace the o-ring on the pin you need to remove the injection pump from the engine to do the repair, it is an easy job but it takes a bit of disassembly to get to it.

I am not the expert on how long the fuel pin needs to be with a deeper cut profile, but if you were to replace it, it would need to be the exact diameter and have a mirror finish or it would cut up the new o-ring. Is this what you were talking about?

Here are the instructions.
https://www.dieseltruckresource.com/...d.php?t=153154

Jim

 

That's it, Jim. I know what it entails, I was wondering if I needed to lengthen the pin or just swap the o-ring and be done with. I'm not sure how much deeper I cut my pin but it's a noticeable difference just looking at it and my o-ring didn't leak before I cut the pin.

 

Sounds familiar!!!!!!! I am having the exact same issue right now. I have a bag of exact size replacement o-rings for the little pin. The original O-ring I pulled out was green in color. The new one is a black Nitrile O-ring. I would be interested to see how others are resolving the O-ring leak issue with a performance fuel pin.

 

your issue is still not fixed? what about running your stocl pin?

 

Yup, not fixed..............The AFC housing fills up with Diesel fuel, no matter if I run your pin or the stock one. The only way diesel fuel can be leaking into this region of the pump is the small O-ring that is on the little pin. I replaced the O-ring with a new one Summer of 07'. I have not seen any external leaking until I swapped in your performance pin. I have swapped your pin and the stock one 2-3 times.........no difference. Fuel leaks with both different fuel pins.

 

with a new o-ring?
how easy does the little pin pop out?

any chance the o-ring retainer came loose, letting the o-ring fall out?

 

I have not actually dug into replacing the O-ring again, yet. Replacing the small O-ring requires the top of the VE pump to be pulled off. Once off, you have to do some intricate work on removing the small pin. This job took me the better part of a day last time to do. Given: I was new to VE's, no manual, took beer breaks, and carefully disected every part.

I will eventually tear into it again and replace the O-ring once again. Its a decent amount of work, just to find out it will leak diesel fuel again.

 

It is not that difficult to replace the o-ring but there is some work involved, I can remove the fan clutch, break the timing gear and have the pump out within about 20 minuets tops as long as I have all of my tools set out.
The trick is to have all of the proper tools, for me it is easy to remove the inside and lower pump nuts using a manifold wrench and the fuel lines are removed easly with a crowfoot wrench.

Also I use a magnetic tray and I will stick a few rare earth magnets the kind from a hard drive where I am working so I can stick parts to them so and not spend time looking for then when the fall into the engine.

For me I have the opposite problem, the pin seems to get stuck and gets tight enough that it will not follow the profile of the pin, The guy a the Bosch repair shop gave me a few of them. It seems that if you over tighten the retainer it will compress the o-ring a bit too much and tighten it up on the pin so t is harder to move.

If you haven’t removed the pin and replaced the o-ring before it will have a buildup of crud on the backside of the pin behind the o-ring and once it starts to move deeper into the profile this will cause the part with the thicker crud to pass through the o-ring and make the hole slightly bigger.

Here is a thought about the different pin causing a leak, is there a possibility that you have also increased the fuel pressure with a different lift pump and causing the internal case pressure to be higher and leak past the o-ring?

Jim

 

Seals do go bad............ULSD and having the pin moved past its comfort zone will sometimes cause a leak. If that ones leaking theres a good chance your do for an input shaft seal and others as well.

 

Are you sure you used the right O-ring. It could be pretty easy to put an oring in that looked the right size, but is just enough NOT the right size that it'll leak. I did that on my throttle shaft, soon as it built fuel pressure started leaking, had to take it apart and find a different oring in the reseal kit. They sure looked exactly the same size!