Has anybody torqued high pressure fuel lines twice?

dragstang86 · September 28, 2022

So on my wife's 2017 Sierra 6.2 I am finishing up an engine rebuild and AFM delete. The high pressure lines, well #12677002 is back ordered everywhere. The lines that I have, were only on the truck for about 5 miles. It broke a lifter, I replaced the lifter and replaced the lines when I did it and 5 miles after putting it all back together, the cam bolt/VVT solenoid broke so I pulled it out and just did a full rebuild and delete. Now since I can't find the one line, I'm wondering if I could get away with using these twice. Has anyone tried it? Did you polish the ball end before doing so? Put a pound or two extra torque on it? It would be frustrating now that I have the engine almost assembled to put it in the truck and sit for who knows how long on a fuel line.

midwestdenaliguy · October 3, 2022

This dealership near me has 4 in stock and they'll ship to your house. https://www.gogmparts.com/oem-parts/gm-fuel-rail-crossover-tube-12677002

You might be able to get away with torqueing the line twice, but with shipping this should be under $50 to not chance it. Good luck.

movario · October 3, 2022

I wouldn't try it. I guess there is a reason why GM even puts a label on the pipe that you need to replace it after unscrewing. I guess if you would use that pipe again you would probably overtighten it or something else.

Grumpy Bear · October 4, 2022

I wouldn't have a problem with it. I don't throw away brake calipers after bleeding them or buy new lines when changing masters. Same pressure on hydraulic brakes as there is on GDI high side pumps and GDI lines are not flare fittings. Whimpy steel brake lines have a minimum burst of 5,000 psi and most will go at least 15,000. Fuel lines are robust.

It's not a torque to yield fitting. Not at 22 lb/ft torque on a ball nut it isn't. You stand the same chance of ruining a new fitting as you do a used one. So I'm not seeing the issue other than the $70 price tag you won't be robbed for. But hey, it's just an opinion and I'm not giving anyone permission or cause to sue me...

rav3 · October 4, 2022

I personally think it's more of a liability issue for GM. If for some reason they did leak & cause a fire, GM could be liable for the event...hence they cover themselves by saying 'replace' it. BMW doesn't require the fuel lines to be replaced on their high pressure fuel lines. Not sure if that's relative or not. Just sayin....you decide for yourself.

Edited October 4, 2022 by rav3

movario · October 4, 2022

4 hours ago, Grumpy Bear said:

I wouldn't have a problem with it. I don't throw away brake calipers after bleeding them or buy new lines when changing masters. Same pressure on hydraulic brakes as there is on GDI high side pumps and GDI lines are not flare fittings. Whimpy steel brake lines have a minimum burst of 5,000 psi and most will go at least 15,000. Fuel lines are robust.

It's not a torque to yield fitting. Not at 22 lb/ft torque on a ball nut it isn't. You stand the same chance of ruining a new fitting as you do a used one. So I'm not seeing the issue other than the $70 price tag you won't be robbed for. But hey, it's just an opinion and I'm not giving anyone permission or cause to sue me...

I don't suspect that the line itself would burst or leak, but i guess the fitting is (or at least could be) the problem.

3 hours ago, rav3 said:

I personally think it's more of a liability issue for GM. If for some reason they did leak & cause a fire, GM could be liable for the event...hence they cover themselves by saying 'replace' it. BMW doesn't require the fuel lines to be replaced on their high pressure fuel lines. Not sure if that's relative or not. Just sayin....you decide for yourself.

The reason here would be that BMW uses a completely different type of fitting. Those are reusable, yes.

Im just saying that, because as a (ex)tow truck driver, I saw a lot of "you don't need to replace that, even though the manufacturer says you have to" fail and cause a lot of trouble.

Newer (Euro) VWs require that the oil plug needs to be replaced after every time. Had a lot of them fail (stupid construction) because they weren't replaced. Or brake caliper bolts and so on.

Edited October 4, 2022 by movario

rav3 · October 5, 2022

Any idea why, if the fitting is so concerning of one-time use, that GM would use this type?

JONBLARC7 · October 6, 2022

Done it more than once on my truck and never had a problem. If you search the corrvette forums, they say the same thing.

newdude · October 6, 2022

On 9/27/2022 at 11:25 PM, dragstang86 said:

So on my wife's 2017 Sierra 6.2 I am finishing up an engine rebuild and AFM delete. The high pressure lines, well #12677002 is back ordered everywhere. The lines that I have, were only on the truck for about 5 miles. It broke a lifter, I replaced the lifter and replaced the lines when I did it and 5 miles after putting it all back together, the cam bolt/VVT solenoid broke so I pulled it out and just did a full rebuild and delete. Now since I can't find the one line, I'm wondering if I could get away with using these twice. Has anyone tried it? Did you polish the ball end before doing so? Put a pound or two extra torque on it? It would be frustrating now that I have the engine almost assembled to put it in the truck and sit for who knows how long on a fuel line.

Seen them leak at work, do not advise it.

Grumpy Bear · October 7, 2022

8 hours ago, newdude said:

Seen them leak at work, do not advise it.

So....you have done it

KARNUT · October 7, 2022

How do they do a fuel system flush? Do they replace any lines with that procedure? I only had it done once, never did it myself. Doesn’t seem plausible. But with every new vehicle it’s always good to do research to see if the rules have changed. The first set of plugs I put in aluminum heads I was surprised to learn to put grease on the plugs. Never done that before. Some vehicles maybe all now. You can’t push brake fluid back to the master cylinder. Every time you buy a GM they change the type of fluids. If they could figure out a way to use a single use item and save a penny it’ll happen. Common sense doesn’t apply.

newdude · October 7, 2022

41 minutes ago, KARNUT said:

How do they do a fuel system flush? Do they replace any lines with that procedure? I only had it done once, never did it myself. Doesn’t seem plausible. But with every new vehicle it’s always good to do research to see if the rules have changed. The first set of plugs I put in aluminum heads I was surprised to learn to put grease on the plugs. Never done that before. Some vehicles maybe all now. You can’t push brake fluid back to the master cylinder. Every time you buy a GM they change the type of fluids. If they could figure out a way to use a single use item and save a penny it’ll happen. Common sense doesn’t apply.

It would be similar to what they want done on diesel engines for metal or DEF contamination. Flush the tank, flush the lines from the tank to the engine, replace the injectors and high-pressure fuel pump, high pressure fuel pipes (because 1 time use) as well as the in-tank pump.