Fuel fitting sizes

Cougar281

Well-known member
Sep 11, 2006
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St Louis, MO
So LONG ago, I bought and installed Kennedy Twin lift pumps, along with the billet pickup, and got it all installed. It's been so long that I don't recall the exact details, and the billet pickup instructions seem to be gone from Kennedy's site, but I seem to recall moving the vent to a smaller line coming from the sending unit and using the original vent line for something else.

Lately, I've had an issue with 'fuel weep'. It's not dripping, but I seem to be getting 'seep and creep' where it never actually drips on the ground, but sometimes when it rains, some gets washed off and is evident on the driveway.

The way I did it back then was some form of fuel hose, pushed over the factory lines and hose clamped. I'd like to look at changing to a better situation.

It seems these days there are fittings that will connect to the factory hardlines and allow AN fitting connections. Does anyone know what size the fuel lines are (so what adapter I'd need), along with what AN fittings size and a recommended braded hose size/brand?
 

ZeroGravity58

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Mar 23, 2008
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I think the the kennedy pickup was 5/8. You can get a tube to an fitting. They work but sometimes hard to seal up on steel
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
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Central OH
Correct on the 5/8" feed line. I believe the 5/8 is the OE vent and the new pickup tube is swapped to feed through that to the pump. Then the vent is switched to the old feed line port
 

Cougar281

Well-known member
Sep 11, 2006
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St Louis, MO
Yeah, that sounds right. So I'd need a 5/8" adapter for the top of the tank, what is the stock line? 1/2"?

Why would these adapters have issues sealing on steel lines? They work on the same principal as the OE spring lock fittings (O-rings) except they don't use a spring lock and instead use a threaded insert to lock it all in place.
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
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Central OH
Link to the fittings you're looking at?

I want to say the OE feed line is 3/8 at the bulk head? Then moves to 1/2. Haha hell idk
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
3,906
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Central OH
I don't see an issue with that style. Like you said, it's still an oring seal like factory. I have a feeling most issues with this type adapter stem from sub standard brands and oring type. Honestly though you might just be getting some weep from a rusty sending unit or a dry rotted rubber hose
 

Cougar281

Well-known member
Sep 11, 2006
1,969
390
83
St Louis, MO
I don't see an issue with that style. Like you said, it's still an oring seal like factory. I have a feeling most issues with this type adapter stem from sub standard brands and oring type. Honestly though you might just be getting some weep from a rusty sending unit or a dry rotted rubber hose
No, the top of the tank seems bone dry. It seems to be coming from somewhere else, but with the way diesel creeps, it's hard to really pinpoint. Could be a hose for sure, but if I'm going to redo it, I'd like to redo it better.

I know one of the ways Kennedy suggested to mount the pumps was to bolt them to the metal heat shield on the side of the tank. Any reason NOT to do that? Seems that would make the plumbing much cleaner.
 

PureHybrid

Isuzu Shakes IT
Feb 15, 2012
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Central OH
Heat shield seems kind of flimsy IMO. Mine are bolted to the cross member right next to the tank, I'll try to get a picture
 

JoshH

Daggum farm truck
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Feb 14, 2007
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You could cut the steel line out and install an AN bulkhead fitting. That's what I did on my stock fuel housing with the PPE billet pickup.