Spill Return Rail Leak

Tbaumer

Technical Excellence Contributor
Started leaking diesel while driving. I could smell it, but coincidentally I had just filled a couple cans in the back of my 110 & thought the smell was from them. It wasn't until I stopped & noticed the trail of fuel behind me that I knew I had a problem. It only leaked when the engine was running & it leaked a lot - from a loose banjo bolt on the spill return rail to one of the injectors. Easy fix, just snug it up until it stops leaking. Then I Dumb-Assed it & snapped the head of the banjo bolt off. Fortunately I had a few old ones back home on a spare tdi engine. When I removed a couple (one for the fix & one for a spare to keep on the truck) I noticed the copper washers are thicker (or two have crushed together seamlessly). Have I been using the wrong copper washers since replacing my injectors? These banjo bolts have come loose before. I used the old thicker washers & tightened gently.

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Tbaumer

Technical Excellence Contributor
As a follow up question, What would one do in the middle of nowhere if this happened & you had no spare banjo bolt? It has to a bad idea, but what would happen if you plugged the spill rail tube to one injector & put a solid bolt in the injector to keep it from leaking?
 

erover82

Well-known member
As long as the washers are real copper, I wouldn't think thickness makes much difference. Copper does work harden after deformation so ideally they should be replaced with each use. The Cummins return washers appear to be about the same thickness as standard LR ones.

If this happened in the bush I'd try to affix a hose to the remaining exposed banjo bolt to either feed the fuel back into the return pipe or into a collection container for filtering and re-use.

I think plugging the return would result in excess fuel being injected, and possibly dramatic component failure due to over pressurization.
 

Tbaumer

Technical Excellence Contributor
I'll be keeping an extra banjo bolt, washers & a length of hose on board from now on. Not that I plan on ever breaking one again.
 

Tbaumer

Technical Excellence Contributor
Is there a secret I'm missing in regards to tightening the banjo bolts without over tightening them, so they don't come loose & start leaking again? Had another (different) one come loose today. Seems like it happens after driving on bumpy off road terrain. Reveals itself with the smell of diesel & it's easy enough to snug up, but I would like to have them stay sealed.
 

erover82

Well-known member
Guessing the Cummins-style washers are less prone to loosening since their rotation is locked together. Otherwise, a single drop of Permatex 24027 or other surface-insensitive thread locker might do it. I'd still try to clean the male and female threads with solvent first though.
 
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