So I posted back in November about my pump springing a massive fuel leak out of the vent tube. I finally got around to fixing it. I pulled the top of the pump off and started disassembly. Pulled the plug out to get to the oring sealing nut and THERES NO NUT. Now I drove it home about 350 miles with it pouring fuel out by plumbing a hose from the vent to the gas tank, so one would think if the nut fell into the pump it would have smashed the internals, but its fine. Traced my steps from the truck to shop bench, didnt see it, its not anywhere on the bench. Its just gone.

Going to drain the fuel in the pump and give it a real good inspection, but didnt find anything using a magnet. its just a mystery where it went. But the hat is ready to go, just really wanna solve the mystery of the missing retainer. Heres a photo of what it looked like when I pulled it off.

 

Can you post a pic with an arrow pointing to the nut you lost? If it's the nut on the fuel screw at the top of the pic then I would think any nut would do. It's not special. If it wasn't tight it could have just rattled off while you were driving.

 

Its the internal nut on the silder pin. I bought a new one, but where did the old one go? Thats why it was streaming fuel from the pump vent.

 

Hmmm it couldn't have gotten away as it is behind a cap to the outside so possibly the PO did not install it?

 

If the nut backs off if can fall down past the fulcrum. I think the mistake I made pulling the hat off was I pulled the diaphram and pin off before removing the hat. That moved the slider pin back and allowed the retaining nut to fall. Otherwise it would have rested on the slider. Guess Im going fishing for that nut... Imagine if that steel plug is in the lower pump and I started it. 😢

 

According to the parts book, after the bushing (the one you pictured) is a sealing washer, then a cup, then a threaded ring on the outer end.

 

Like the 2nd photo, correct?

 

SOLVED..... Yup the reason why the pump had a massive stream of diesel pouring out the vent was the nut back ALL the way out that held the slide pin O-ring and fell into the bottom of the pump. I fished it out today and its been banged around pretty good. Hard to believe I drove 400 miles like that and it didnt break the pump.