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Flexible fuel line. Update - mech fuel pump outlet size?

chalet2506

chalet2506

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I need a new pump to carb line so I went to inlinetube who show 2 part#'s for a 72 4x4 Jimmy. One for an a/c'd 350 with long pump, and a non a/c'd with a short water pump. Bout 99% sure my 72 has a short water pump and a/c.I call them and they say the need measurements and pics to get me the right one or build one. Sounds like a pita as I destroyed the old when when I removed the carb as the little brass fitting was stripped.

So, how hard is it to just get some flexible line and what fittings do I need? Don't trust my skills or my chinese dial caliper. Truck has a 350 and a quadrajet off of a 75ish truck on it.
 
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i just have a plain ole peice of rubber hose that connects the two with a pair of hose clamps....
 
AN fittings and braided line. I just did most of this yesterday on my C10. Put a hardline from my carb, with an aluminum micron filter, pressure gauge. I will be doing a braided line from the end of it down to the fuel pump. Russell makes a 2 foot section for the purpose.
 
Thanks. Guess I'll truck it over to napa tomorrow and see if I can get the fittings, then maybe order the stainless from summit if I have to.
 
Napa wasn't a whole lot of help.

How about this carb fitting and this hose from summit? 3/8 fitting at the fuel pump, 6an female on the hose, 6an male on the carb fitting, and 7/8-20 inch into the carb.

Wonder if the stock fuel filter will work? Doesn't say much about that.

http://www.summitracing.com/parts/HLY-26-73/
hly-26-73_w.jpg


http://www.summitracing.com/parts/EDL-8123/?rtype=10

edl-8123.jpg
 
You think? I'd think the inside diameter of the carb fitting would be the same as the stock one.
 
The stock filter slips inside the fuel inlet that screws into the carb housing.
 
Can you possibly do a little write up on this? im looking to do the same thing and would like to get a idea first.
 
Well ****, apparently all q-jets starting with "170" aren't built after 75 with a 1-20 thread on the fuel inlet. Stock filter is a little tight, but I think it would work fine - if it fit my carb....

Ordered a 7/8 20 inlet and went ahead and got an inline reusable filter and 6an coupling.

Turning into an expensive little project.

http://www.summitracing.com/parts/SUM-230103/?rtype=10

sum-230103_w.jpg
 
So any idea what fitting size the outlet on the mechanical fuel pump is? 3/8 npt elbow that came with the line doesn't fit my pump. Not sure if it's a hair too big or the threads are the wrong size.

Also, filter is bigger than it looks and won't clear the carb coming straight out. Going to order a 45 deg coupler to get around the little vacuum secondaries gizmo. Thought about putting it down by the pump, but too much a/c stuff and radiator hose in the way. Guess maybe a good time to remove the a/c like I've been planning.

Edit: found this on a vette site.

yes, the aftermarket pumps usually have 3/8 pipe like your edelbrock but the stock replacement pumps have a 5/8-18 inverted flare
Click to expand...
 
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MOst of the GM mechanical pumps I've replaced had a 3/8" inverted flare fitting,not pipe threads...some were 5/16" inverted flare on smaller engines or 2 bbl carbs..but I did run into one vehicle that had a 1/8" NPT thread on the fuel pump outlet to the carb!..
 
I just went through this. Didn't know there was different kinds of flares. WTH! Made 3 trips back and forth to auto parts house before I compared my old stock 3/8 steel line fitting to their 3/8 steel line. The flare on the new line was smaller than the stock flare. And dammit that's the size I was looking for. The new fuel line just said standard flare on it. That's about the most info I got out of the whole ordeal. I went as far as pulling up the cut sheet on the new mechanical fuel pump to find my connection. All could find anywhere was 5/8 thread, 3/8 tubing. Can someone who knows enlighten me on the flare types?
 
Most everything on a pre-1978 GM vehicle used "normal" SAE thread inverted flare fittings...after that they started using some metric thread fittings with bubble flare tubing..

What I've done with most of my older carbed GM engines was ditch the fuel filter inside the carb and put a universal in line gas filter in the metal line going from the fuel pump to the carb..a metal one,I've had plastic ones fail before and nearly burn the truck to the ground..use short pieces of rubber fuel line to connect it to the tubing with clamps..

All I ever did was cut the oem tubing going to the carb or get a new length of brake line with the right sized thread and tube size, and bend up a new steel line,leaving about 4" of space between the carb and pump to insert the new in line filter..

Fancy braided hoses and race car fuel filters might look nice,but if that filter plugs up somewhere you had better keep a spare with you--you can buy the universal ones just about anywhere..here's a tube size to SAE thread chart...tube thread pitches.png
 
diesel4me said:
Most everything on a pre-1978 GM vehicle used "normal" SAE thread inverted flare fittings...after that they started using some metric thread fittings with bubble flare tubing..

What I've done with most of my older carbed GM engines was ditch the fuel filter inside the carb and put a universal in line gas filter in the metal line going from the fuel pump to the carb..a metal one,I've had plastic ones fail before and nearly burn the truck to the ground..use short pieces of rubber fuel line to connect it to the tubing with clamps..

All I ever did was cut the oem tubing going to the carb or get a new length of brake line with the right sized thread and tube size, and bend up a new steel line,leaving about 4" of space between the carb and pump to insert the new in line filter..

Fancy braided hoses and race car fuel filters might look nice,but if that filter plugs up somewhere you had better keep a spare with you--you can buy the universal ones just about anywhere..here's a tube size to SAE thread chart...View attachment 254375
Click to expand...

I actually have a brand new Edelbrock 1826 carb, so already have an inline filter. It's also new and metal too, but good to know about the plastic fire hazards.
I guess what found that worked then was the same 5/8 threaded fitting with a bubble flare on 3/8 tubing that worked. What I did is working but it's not pretty. I used a tubing bender that didn't have the right size 3/8. Ended up going out and around the side of alternator. And almost buckled the tubing. I need to find a tubing bender that's actually the right size and rebend a new piece. I would just order a prebent line but can't find info on the flares.
 
Copper can be used in that fuel line location,as long as you don't run it as a one piece flared unit like the OEM steel line was from the pump to the carb--as long as you have the filter installed in-line with it with short rubber hoses,that will prevent it from vibrating and cracking at the flare..

I have used copper on many of my trucks,another plus is it cant rust....copper is softer,easier to bend without kinking it ,you could also use that new Nickel-Copper brake tubing too..

I haven't had much luck bending steel tubing larger than 5/16,anything bigger is so thick walled it usually wants to kink before it'll bend..I've tried tubing benders,but I have better luck using an old V-pulley in a vise to make bends in it..3/8" and larger is beech..
 
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