Fuel hard line to rubber connections

K

kmorefield

Member
Jan 4, 2020
62
6
8
Hi all,
I've been reading through years of postings, photos, etc. I'm still a bit uncertain. I have my fuel tanks dropped and am in the process of replacing
parts and pieces (rubber). At a minimimum, I want to run hard lines on top of the tanks. I will cut access holes in the floor, in order to access
the fuel senders and in-tank pumps (I ordered the in tank electric pumps from Jim K). My question is regarding connecting the hard line to rubber
lines at the edge of the tanks - do I need to flare the line in some way, in order for the rubber fuel line and hose clamp to have something to bite
onto? Or do you guys use a compression fitting with a hose barb? Most pictures that I've seen posted, make it appear that the poly-armour lines are
cut to size, but I'm not sure I've ever seen how they actually are fit to the rubber lines.
What are the opinions these days regarding fuel sender to hard line connections? It seems like some have used a short section of rubber line, and
some have used compression fittings - knowing that I'll have access through the floor from above, which option seems the most trouble free? Go easy
on this newbie - I hope I'm not further beating a dead horse!

Ken
--
1975 - 26’ Eleganza II
Unsure of what upgrades may have been done. I'm working on sorting that out in the coming months.
Ken Morefield - Redding, CA
 
Ken i would flare any hose to line connection and use EFI clamps [some call them band clamps] and not the gear clamps.... or your just going to have
leaks.

I'm not a fan of compression fittings when joining fuel lines, i know people do it with success just not my preferred way....JMHO
--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Be very careful when using rubber hose over flared fittings. Those
fittings typically have fairly sharp edges which can easily cut through the
rubber hose, especially if there's a clamp placed too close to the flare.
Double flared fittings, with their rolled flare edge are a lot better, but
still not my preference. Best is a formed bubble near the end of the hard
line. Since few have a way to make those, a compression ring is probably
easier. I take a coupling of the appropriate size for the line. Install
the coupling nut on the line, then the compression ring, then the coupler.
When the nut's tightened on the ring, that will be permanently seated on
the line. Remove the coupling and install the tubing, with its clamp
"behind" the compression ring, which acts as the retainer. Unfortunately,
the compression nut will remain on the hard line. If that really bothers
you, you could cut it off with a Dremel tool, I guess.

JWID,

Ken H.

On Thu, May 21, 2020 at 1:04 PM 6cuda6--- via Gmclist <

> Ken i would flare any hose to line connection and use EFI clamps [some
> call them band clamps] and not the gear clamps.... or your just going to
> have
> leaks.
>
> I'm not a fan of compression fittings when joining fuel lines, i know
> people do it with success just not my preferred way....JMHO
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Ken,

Some number of years ago (actually 8 - I just looked it up), I did everything with Polyarmor and J30-R14 hose and a minimum of that. Where I needed
to connect the metal to rubber, I just did the first part of a double flare and left it that way.

To attach to the pick-ups, I borrowed Emory's plan and used and cut the bubbles off so I could make that joint with a brass compression fitting I
wanted no rubber over the tanks.

There is now less than 6 feet of rubber in the entire fuel system.

Matt
--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
Matt,

Good idea leaving the double flare only "half done" -- I should have
mentioned that option. For those not familiar with the making of double
flares: The first step is to insert a "inverter plug" (don't know what
else to call it) into the cut end of the tube to be flared. That plug
mates with the forcing cone of the flaring tool and is shaped on the tubing
side so that it forces the tubing to expand a short distance from its end,
where it retains its original size. At that point, there is a "bubble" at
the end of the tubing, a perfect retainer for rubber tubing to fit over.
To complete the double flare, the "plug" is removed, allowing the forcing
cone of the tool to press the open end of the tubing into the bubble,
completing the double flare. That last step is not needed if it's not to
be a flare connection.

Ken H.

On Thu, May 21, 2020 at 2:31 PM Matt Colie via Gmclist <

> Ken,
>
> Some number of years ago (actually 8 - I just looked it up), I did
> everything with Polyarmor and J30-R14 hose and a minimum of that. Where I
> needed
> to connect the metal to rubber, I just did the first part of a double
> flare and left it that way.
>
> To attach to the pick-ups, I borrowed Emory's plan and used and cut the
> bubbles off so I could make that joint with a brass compression fitting I
> wanted no rubber over the tanks.
>
> There is now less than 6 feet of rubber in the entire fuel system.
>
> Matt
> --
> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> Electronically Controlled Quiet Engine Cooling Fan
> OE Rear Drum Brakes with Applied Control Arms
> SE Michigan - Twixt A2 and Detroit
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Yes Ken is correct...the term i should have used was "bubble flair".

> Be very careful when using rubber hose over flared fittings. Those
> fittings typically have fairly sharp edges which can easily cut through the
> rubber hose, especially if there's a clamp placed too close to the flare.
> Double flared fittings, with their rolled flare edge are a lot better, but
> still not my preference. Best is a formed bubble near the end of the hard
> line. Since few have a way to make those, a compression ring is probably
> easier. I take a coupling of the appropriate size for the line. Install
> the coupling nut on the line, then the compression ring, then the coupler.
> When the nut's tightened on the ring, that will be permanently seated on
> the line. Remove the coupling and install the tubing, with its clamp
> "behind" the compression ring, which acts as the retainer. Unfortunately,
> the compression nut will remain on the hard line. If that really bothers
> you, you could cut it off with a Dremel tool, I guess.
>
> JWID,
>
> Ken H.
>
>
> On Thu, May 21, 2020 at 1:04 PM 6cuda6--- via Gmclist <

>
> > Ken i would flare any hose to line connection and use EFI clamps [some
> > call them band clamps] and not the gear clamps.... or your just going to
> > have
> > leaks.
> >
> > I'm not a fan of compression fittings when joining fuel lines, i know
> > people do it with success just not my preferred way....JMHO
> > --
> > Rich Mondor,
> >
> > Brockville, ON
> >
> > 77 Hughes 2600
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
Yup...thats the way....works a charm. They do sell a bubble flair tool as well but unless you were going to use it everyday the way Ken described
works just as good.

> Matt,
>
> Good idea leaving the double flare only "half done" -- I should have
> mentioned that option. For those not familiar with the making of double
> flares: The first step is to insert a "inverter plug" (don't know what
> else to call it) into the cut end of the tube to be flared. That plug
> mates with the forcing cone of the flaring tool and is shaped on the tubing
> side so that it forces the tubing to expand a short distance from its end,
> where it retains its original size. At that point, there is a "bubble" at
> the end of the tubing, a perfect retainer for rubber tubing to fit over.
> To complete the double flare, the "plug" is removed, allowing the forcing
> cone of the tool to press the open end of the tubing into the bubble,
> completing the double flare. That last step is not needed if it's not to
> be a flare connection.
>
> Ken H.
>
>
> On Thu, May 21, 2020 at 2:31 PM Matt Colie via Gmclist <

>
> > Ken,
> >
> > Some number of years ago (actually 8 - I just looked it up), I did
> > everything with Polyarmor and J30-R14 hose and a minimum of that. Where I
> > needed
> > to connect the metal to rubber, I just did the first part of a double
> > flare and left it that way.
> >
> > To attach to the pick-ups, I borrowed Emory's plan and used and cut the
> > bubbles off so I could make that joint with a brass compression fitting I
> > wanted no rubber over the tanks.
> >
> > There is now less than 6 feet of rubber in the entire fuel system.
> >
> > Matt
> > --
> > Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
> > Electronically Controlled Quiet Engine Cooling Fan
> > OE Rear Drum Brakes with Applied Control Arms
> > SE Michigan - Twixt A2 and Detroit
> >
> > _______________________________________________
> > GMCnet mailing list
> > Unsubscribe or Change List Options:
> > http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
> >
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org

--
Rich Mondor,

Brockville, ON

77 Hughes 2600
 
I don’t have any rubber at all in my fuel lines. T steel lines are connected to my pickups with compression fittings after I cut off the “bubbles”

Emery Stora

>
> Yup...thats the way....works a charm. They do sell a bubble flair tool as well but unless you were going to use it everyday the way Ken described
> works just as good.
>

>> Matt,
>>
>> Good idea leaving the double flare only "half done" -- I should have
>> mentioned that option. For those not familiar with the making of double
>> flares: The first step is to insert a "inverter plug" (don't know what
>> else to call it) into the cut end of the tube to be flared. That plug
>> mates with the forcing cone of the flaring tool and is shaped on the tubing
>> side so that it forces the tubing to expand a short distance from its end,
>> where it retains its original size. At that point, there is a "bubble" at
>> the end of the tubing, a perfect retainer for rubber tubing to fit over.
>> To complete the double flare, the "plug" is removed, allowing the forcing
>> cone of the tool to press the open end of the tubing into the bubble,
>> completing the double flare. That last step is not needed if it's not to
>> be a flare connection.
>>
>> Ken H.
>>
>>
>>> On Thu, May 21, 2020 at 2:31 PM Matt Colie via Gmclist <

>>>
>>> Ken,
>>>
>>> Some number of years ago (actually 8 - I just looked it up), I did
>>> everything with Polyarmor and J30-R14 hose and a minimum of that. Where I
>>> needed
>>> to connect the metal to rubber, I just did the first part of a double
>>> flare and left it that way.
>>>
>>> To attach to the pick-ups, I borrowed Emory's plan and used and cut the
>>> bubbles off so I could make that joint with a brass compression fitting I
>>> wanted no rubber over the tanks.
>>>
>>> There is now less than 6 feet of rubber in the entire fuel system.
>>>
>>> Matt
>>> --
>>> Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
>>> Electronically Controlled Quiet Engine Cooling Fan
>>> OE Rear Drum Brakes with Applied Control Arms
>>> SE Michigan - Twixt A2 and Detroit
>>>
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
>
> --
> Rich Mondor,
>
> Brockville, ON
>
> 77 Hughes 2600
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
I would put a threaded fitting on the hard line and flare it, then thread a bayonet fitting onto it, and clamp the rubber to the bayonet. That's what
they're for. Since you have in tank pumps, all the fittings are under pressure. Anywhere there's rubber to metal, use a bayonet fitting and a clamp.
Here's a picture of one done that way:

http://www.gmcmhphotos.com/photos/cane-9-creek-rv-park-heflin-2c-al/p58467-fuel-pump-follies.html

That is the rubber hose from the hard line across the frame member to the hardline to the carb. The hardline was unscrewed from the pump, and a
threaded bayonet fitting used.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
> I would put a threaded fitting on the hard line and flare it, then thread a bayonet fitting onto it, and clamp the rubber to the bayonet. That's
> what they're for. Since you have in tank pumps, all the fittings are under pressure. Anywhere there's rubber to metal, use a bayonet fitting and a
> clamp. Here's a picture of one done that way:
>
> http://www.gmcmhphotos.com/photos/cane-9-creek-rv-park-heflin-2c-al/p58467-fuel-pump-follies.html
>
> That is the rubber hose from the hard line across the frame member to the hardline to the carb. The hardline was unscrewed from the pump, and a
> threaded bayonet fitting used.
>
> --johnny

Johnny,

I think you mean a barb fitting. I have some bayonet fittings to hose for special purposes and they are expensive and unreliable.

Matt

--
Matt & Mary Colie - '73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan
OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Twixt A2 and Detroit
 
I used the two terms interchangeably, which is a mistake.. Barb fitting is correct. Bayonet is what fits the slinky on the outlet.

Emery, when you say your coach is all hard fuel line, how do you handle engine vibration relative to the frame?

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
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