Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

My current hard line is a bit tired from previous owners not likely using a flare nut wrench and also looks like the line has been bent around a few times too. I bought a hard line from Summit Racing, actually this is my second one and the best I can get it is perhaps 2~3 drops a second of leakage. I tried the lapping method for over 30 minutes, never got it better than the 2~3 drops a second. Both of the lines I got from Summit Racing acted the same way.

So I am giving up on Summit and have ordered one from GMCPaul's and put the old one back on. I thought I bought the steel line but I see from my email confirmation I got the stainless steel one.

I know these lines do not take any sealer, tape, dope, etc. Any other tips out there for when I get my GMCPaul's line in? Should I also reach out to GMCPaul's to switch the stainless steel to regular steel one?

Thanks for helping me NOT setting my trunk on fire :devil:

GMCPaul's

Pump To Carb Stainless Steel Line SB V8 W/Long Pump & A/C
1971-72 1/2 & 3/4 Ton truck, Suburban, Blazer / Jimmy 2 wheel drive fuel pump to carburetor line V8 350ci manufactured in stainless steel and CNC bent exactly like original, for 350ci motor with long bowl fuel pump & A/C.
Proudly Made In the USA

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

You don't need tape on the threads. The seal is created at the flare. Maybe the mating surface on the fuel pump is nicked causing all the lines to leak. Fuel pumps are cheap if that's the answer

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

agreed, about tape/sealer. The old line doesn't leak like the others, though perhaps it has mated itself up to the fuel pump "nick" - if that is where the problem is at.

Other than O'Rileys and such - any recommendations, so I can be looking into that too - if need be?

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

I bought mine (Delphi) from Rockauto.com.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

having problems finding mine. I see there are short and long, then 2 or 3 lines. Mine looks like a short 3 line fuel pump but I cannot find one.


Edit: So perhaps a previous owner put this on that goes to something like a Nova? Any site I go to its either a short two line or a long 3 line. There are no short 3-line fuel pumps that are called out for a 72 C10 SBC350 - that I can find. Rock Auto, O'Riley's, AutoZone Advance Auto Parts. So mine has to be wrong?

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

This it? Picture looks the same.
1972-1974 Chevrolet C10 Pickup Fuel Pump Carter:chevy:

https://www.partsgeek.com/gbproducts...QaAtS6EALw_wcB

https://www.partsgeek.com/assets/dim...72-1269907.jpg

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Put one of those chrome duel feed hard lines to both float chambers.

After going back to the store for an exchange, they both leaked like crazy! :mad:

Finally applied thread tape to the fittings and that solved the problem.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Hi Andy,

That is what I am more or less looking at on RockAuto (and other sites) for a 3-line Fuel pump for a 72 C10 350. I am pretty sure that lower can is longer than what is installed on my C10 with a 3-line hookup.

On my 72 truck (the way I got it) it has a Short 3-line Fuel pump but all the short ones are 2-Lines (for a C10 72). Parts store list only a Long Fuel pump for 3-lines. Sticking with Delphi, this is a part number of MF0055 on RockAuto.

Since clearly they make a Short 3-Line Fuel Pump and I found it on RockAuto for a 72 Nova but it is also called out for a 73 C10. This Delphi part number is MF0002.

I looked at my Chevy manuals and I only found one place about the Fuel Pump and it was only a few pages long and only showed the short two line version.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

The 71-72 had the emission stuff on them that maybe what the third line is for.:chevy:

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Summit has them. For all small block motor no matter what the vehicle is. They all will work.

https://www.summitracing.com/parts/c...8aAvZXEALw_wcB

https://static.summitracing.com/glob....jpg?rep=False

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

that is one big photo!

Yep, I can see how to get one for sure and I am 100% sure you are correct about the emission stuff with the 3-line.

What took me down this rabbit hole was ordering from GMCPauls the correct hard fuel line between carb and fuel pump. He has quite a few options for a 350. Long, Short, with or without A/C. The thing is, Paul doesn't have one listed for Short Fuel Pump with A/C.

I just clicked away and ordered a "Pump To Carb Stainless Steel Line SB V8 W/Long Pump & A/C listed for 1971-72". Then I thought, wait, my pump didn't seem very "Long" how could it be shorter??? So this is where I am at now.... Get the wrong line, it will not route right and be too short.

Anyways, I am fussing about getting the correct pump and hard line - might as do it correctly (is what I been thinking).

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Yea that is correct you will need the right one. Are you going hard line all the way to the carburetor? If not just cut the top off and put a half flare on it and rubber gas line with a in line filter call it good.:chevy:

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Yes, hardline from Pump to Qjet 4BB.

So it seems if I get the one that I actually ordered from GMCPaul's (hardline that is), a 72 3-Line Long Fuel Pump is in order... or at least that is how I am reading the tea leaves.

Really wished I knew how it got a short fuel pump or if there was some last moment change with the 72 C10 Emissions (fuel vapor canister lines) where they sub the 3-line long with a 3-line short. They are surely around for 72 (on the Nova, Monte Carlo and then starting for the 73 C10).

Ugh I hate when things don't line up, really kicks in my OCD!

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Another note, if going to a 3-Line Long Fuel Pump, it would be about 1 1/2 longer (closer to the ground). That is going by Delphi dimensions of 4.5 x 3.5 x 6 inches (Short MF0002) and 4.2 x 4.2 x 7.5 inches (Long MF0055).

Also the Short is 9 PSI (Average Flow Rating/GP of 40) and the Long is 8 PSI (Average Flow Rating /GP of 65)

Not sure if the PSI/GP is any kind of factor at all. I guess these are not 5 PSI since they are 3-line (I swear I read the carb was suppose to have 5 PSI).

Lastly here is a photo, the lines from the fuel take (hard to soft) appear to match up at the correct level for this Short guy. I'd image there would be a downward slop with the long.... maybe my soft lines would not reach properly?

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Well if it doesn't work you can go buy the fuel line at auto store and a double flare tool and make your own lines. It's easy enough as long as you take your time making the bends.

I made all the fuel lines and brake lines for the 68 step I built.:chevy:

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Very true, new soft fuel lines would be zero issues.

Creating a hardline, well I'd need a pipe bender and the a double flare tool. Likely something that I'd never use again or pretty sure of that. Plus I am sure there would be a learning curve before I got it right. My skin is already pealing off as it is with today's work LOL

My actual point I was trying to make and I see I wasn't clear at all. If everything appears to line up for a short fuel pump, that seems a lot of work for someone to go through to change from Factory short to long. I guess it is possible when it was restored they made their lines to a short pump they picked up 10 years ago... Basically its just me trying to solve the 3-Line short fuel pump that appears to be out of place/time with my C10. waaaaa

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Does this remain the problem? You have a hard line you would like to use and you attach the hard line and snug it up and it leaks? This is my solution, no more leaks. Copper flare gaskets. I'll never install another hard line at the pump, nor re-attach the hard line to the carburetor after changing the filter, without using one. Easy, cheap, pain free. https://67-72chevytrucks.com/vboard/...d.php?t=762179

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

At the moment, no. I put the old line back in. I'll check out your link, thanks! Though I do have to get it pretty tight, more so than I would like!

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

It looks like you got these from Grainger PARKER Flare Gasket, Flare Connection Type, 3/8 in Tube Size.

Could you explain how you used them? This sounds like a pretty good idea to me.


And this single flare washer to the double flare is no issue at all?

Edit
Found this interesting fellow talk about "How to make a flare fitting copper washer to seal a seeping fuel line" on YouTube. I think I get how to use the ones from Grander now...

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Yes that's the part number 5WRW3. You just insert them in the flare fitting. Sandwich one between the steel surfaces of the tube and fitting. When you tighten it up you will only need to tighten a reasonable amount. I think they are pretty wonderful. Without using these gaskets, I tightened the connection at the fuel pump, and tightened it more, and tightened it more and more until finally I had no leak. There was no way to get the connection loose again without destroying the fuel pump. I'm surprised I didn't destroy the fuel pump putting it on. It takes more finesse and patience than I have to mate the steel surfaces and get them to not leak. Now that I have a box of these gaskets, I can whistle while I work, instead of grunting and cussing.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

More info: With the copper gasket I found it was not necessary to do the tightening and loosening and re-tightening procedure to get it to seal, and I have reused the same gasket a couple of times with no problem. If I get a hint of a leak or if the gasket looks scarred, then I use a new gasket. I don't know how to describe how tight the connection needs to be, because I didn't use a torque wrench. I don't think it needs to be very tight, just snug to the point I'm sure it won't vibrate loose.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

So the pointy end goes towards the fuel pump and you don’t need to do a cycle of tighten/loosen before the final snug down?


Edit
I posted this before I saw you newest posting on not doing the cycling back and forth.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

I've never seen those. I watched the video and after watching it I wonder if you could buy a box of brake banjo fittings that would do the same thing. Just a thought. They are copper and thin and made to seal up brake hoses.
This picture they look to thick though & to big.:chevy:


https://images-na.ssl-images-amazon....AC_SL1000_.jpg

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

i am thinking more like this? Not that I have the proper tools to do it...

110pc Copper Washer Assortment Flat Ring Oil Brake Line SAE

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Those flat washers are the wrong shape.
You need a cone shape to seal.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Take a look at my posting with the YouTube, there is a guy that shows you how to make them with a flange tool...

Also, before I wrote the pointy part of the cone goes towards the pump, pretty sure I said that backwards - the pointy part goes into the steel line - like the fellow shows when making a copper washer to in copper flange seal. Just trying to visualize how the steel line, copper flange washer, and fuel pump/carb connection all go together. Likely once I start doing it, it will make sense!

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Holy No Leaks Batman!

UPS dropped off the Copper Flare Washers from Grainger and I just got them installed. I barely snugged them down and it appears to be dry as a bone! I started her up and let the engine run for about 10 minutes or so, which the first few minutes was on choke. I am going to let the gas dry out around the engine compartment and when it's not raining do a quick around the block test. Silly I am thinking, this is working?? Ha!

Posting some photos of my line and washers. The 1st one is just the line and I am trying to show what I think is a hump/seam line. It was a lot worse before I wet sanded it with 500 and 2000 grit sandpaper. Before I sanded I could see a hump on the lip of the flare - perhaps this was some of my problem or perhaps that is normal, heck if I know.

The next two are just showing the washer next to the line and the washer setting on top of the line. I put the washer into the fuel pump and into the inlet of the Qjet Carburetor. When I put them on and wrenched it, I really assumed I'd have to give it a little more but no, there was no leak on my first try. Though I did give it a bit more, since I was sure I was too "lite" with tightening them down. But that is still light years away what I was doing yesterday.

Many thanks dmjlambert! Really, I cannot thank you enough - it's like I need to send you money or something LOL

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Give Me Money! That's What I Want

LOL. Your findings are same as mine. Just insert gasket, problem over.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

LOL love that song.... though why I cannot ever get YouTubes to embed like that!

"check is in the mail" ;-)

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

That's pretty cool. I've never herd of these. I will be checkin' on them though.

Rich72C10, did you order a assortment of them are just the size you needed?

:chevy:

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

I just ordered the 3/8th size from Grainger... though if I ever work on my break lines I'll likely order some of those sizes to have on the self (just in case). But the lines/fittings are in real good shape on my truck and haven't been malformed by using the wrong type of wrench (like my fuel hard line was).

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Okay, one of the things I talked about in this thread was my short 3-line Fuel Pump. Back when I first tried to get my truck from my brother in Kilgore we ended up replacing the Fuel Pump (long story short, it was trash in the tank NOT the pump). Whilst every parts site says I need a "long" 3-line pump, mine has a shorter one (which comes up for a 73+ C10 350 or even a 72 350 Suburban). So I decided to get a new one today after getting fed up with the "new" one and it's super annoying ticking.

Got one from Lockhart NAPA, Delphi #DFP MF0002 (which I think is ACDelco / GM's part source). It more or less looks like the one I took off but rather than the lower can being brass-like colored, it is more stainless of a color. The one I took off, I think is a Carter or at least it has a Carter part number stamped on the side - #M6626. Then under that number it has 20048 listed.

1. The Delphi MF0002 has no clickety-clack. Man, I hated that sound on the "old" one!
2. I seem to have a better / stable idle.
3. When just putting along and hardly giving/touching the pedal it so much smoother as the RPMs reach shifting time. I have had a odd power like loss at low RPMs - unless I was giving a bit more pedal.

Number 2 and 3 above are total bonus changes in operation, I wasn't aware I needed a new fuel pump but I suppose at low RPM the M6626 pump wasn't giving steady fuel? Eh, I don't know but ~$25 bucks for this Delphi DFP MF0002 was well worth twice that cost to just getting rid of the gosh darn ticking!

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

The ticking sound was possibly from a gap between the pushrod and lever arm. Or maybe just poppet noise.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

I don't know what its deal was, it was just annoying as hell. Though now I can clearly hear my water pump making a slight whining / squealing noise. So he'll be getting replaced next I think but it is less annoying.

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Could just be the belt. Didn't the engine get a new or rebuilt water pump when it got rebuilt?

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Getting a new water pump would have been a good idea, in hindsight. I am positive its the water pump giving a bit of a squeaky noise. It isn't all thought loud but I think she is giving me a hit ;-)

What sucks, is that I'm going to have to rattle paint the replacement... if I could only go back in time (hums, Cher – If I Could Turn Back Time).

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

Wonder what it is after the water pump! LOL. It's always the next thing on these old trucks, isn't it? I have a list!

Re: Carb to Fuel Pump Hard Line [Leak at Fuel Pump]
 

You got that right - next up is more or less refreshing the frontend along with tired rubber brake lines - I have like $500 worth of parts in my RockAuto cart (includes water pump to have on hand)! But what I hate is re-replacing parts - hopefully the fuel pump is the last of that from last summer's repairs.

Though it is nice to be in preventive maintenance / peace of mind repairs. I already have a 12 bolt rear end Flo-Pro gasket as the cover is weeping around the bolts. That is when I also noticed the rear center brake line didn't look all that hot. None of these I am looking forward doing and I am serious thinking of having it done for me.