Fuel Return Line Questions Options

[friethmiller]

My Red '74 (a.k.a Denise) is getting a return line but I'm having issues finding the right size return line hose to go between the tank and the SS line. I have a 5/16" (8mm) rubber hose that looks like it might work. Waited 4 days for Sierra Madre to ship a 7mm ID braided hose, which turned out to be > 8mm (just too loose). (IMG:style_emoticons/default/headbang.gif) I want to go with the 5/16" line but I really think both of these ends should be bubble flared. Has anyone done this? Anything to watch out for? Any other solutions here? I don't need these connections leaking or sliding off.

Also, I have a rubber washer on the return pipe and just a brass washer + screen in the feed. Is this normal? Can I use something like Curil T to help seal these connections? Thanks in advance.

[mepstein]

I go to flaps and get whatever high pressure fuel line that fits properly. I just walk into the back and diy. The people there are usually happy they don't need to be involved.

[Superhawk996]

I really think both of these ends should be bubble flared. Has anyone done this? Anything to watch out for? Any other solutions here? I don't need these connections leaking or sliding off.

The bead rolling tools for small diameter tube are rather pricey and each tool only covers a small size range of tubing. If you have the time - you might ask Chris Folley how much he’d charge to bubble roll them for you. Local hot rod / fab shop might have a set too.

Since these lines aren’t under much pressure they aren’t as likely to slip off but as you know, bubble flare is best practice. I was always a little surprised they Weren’t rolled as original equipment.

[Dynosoar11]

The return is very low pressure. I would not change it. The engineers said it was good to leave the factory that way.
Dyno

[Ron914]

I really think both of these ends should be bubble flared. Has anyone done this? Anything to watch out for? Any other solutions here? I don't need these connections leaking or sliding off.

The bead rolling tools for small diameter tube are rather pricey and each tool only covers a small size range of tubing. If you have the time - you might ask Chris Folley how much he’d charge to bubble roll them for you. Local hot rod / fab shop might have a set too.

Since these lines aren’t under much pressure they aren’t as likely to slip off but as you know, bubble flare is best practice. I was always a little surprised they Weren’t rolled as original equipment.

I see what you see , straight ends the bubble flare would give added protection from slipping or coming off if the clamp loosened .
(IMG:style_emoticons/default/agree.gif)

[friethmiller]

The return is very low pressure. I would not change it. The engineers said it was good to leave the factory that way.
Dyno

Yes, and that might be the way it goes. Planning to slow-roll through the FLAPS at lunch today. I'll see if they have anything to flare these ends. If not, I may just go with two fuel clamps.

Thanks for all the input guys! Any opinions on sealant here? Go/No-go? It doesn't seem like a good thing to even try with gasoline. Thought I'd ask though.

[Superhawk996]

I don’t know what you mean by sealant

Definitely a hard no on the lines (IMG:style_emoticons/default/confused24.gif)

The tubes seal to the tank with fiber washers - replacements can be found at Harbor Freight, granger, McMaster-Carr, Amazon, etc.

[technicalninja]

I would use a true circular hose clamp.

Early fuel injected Datsuns had FI clamps that are wonderful. I scrounged many...

Don't use normal worm style clamps.

As long as you can find the proper OD size a spring clamp works well too.

Both of those lines right there have extremely low pressure and thus are not as critical as "between fuel pump and regulator".



I wanted a beader set myself. Did some research a few years back.

The Hawk is RIGHT!

$200+ per size and I want 5.

1K+ worth of beaders would have marital consequences...


Also, I have never found a hose to tube sealant that worked without damaging stuff down the road.

Normally I use my spit to lubricate the hose before installation and, it seems to form a light seal by itself.
Soap might do same thing better.

[friethmiller]

Ok, I talked with a guy at lunch that has a lot of experience working on Porsches of all types. He inspected my feed and return tubes and said if I tried to bubble flare the ends they would likely crack. I instantly remembered cleaning a bunch of rust out of the tubes with a bore brush last night (IMG:style_emoticons/default/blink.gif) Yeah... I'm going to just go with the good quality, smooth-band fuel clamps, my existing lines, and reuse the seals that I had in place before.

Again, thanks for all the input here. Onward! (IMG:style_emoticons/default/flag.gif)

[friethmiller]

This might be like wearing two condoms, I don't know. I have single clamps on the SS lines and double clamps on the tank side. Tank is back in! I'm going to remove the plate from below and inspect the lines just to verify everything is right down below before putting any gas in.

Thanks again to the group for your input. (IMG:style_emoticons/default/beerchug.gif)