Replacing Filler Neck Evap Vent Tube with Copper water pipe

[PlatonicSolid]

In the middle of replacing the fuel tank in the 89 GMC C3500XC and discover the 11” steel Evap pipe attached to the filler neck via 5/8 rubber hose is corroded to the point of having pin holes. Not sure why they didn’t just run a rubber line from the filler neck to the tank. Apparently you can’t purchase the evap pipe alone – only place I’ve found it is in a kit with the filler neck (Summit Link)= $100 by the time it gets to my door. Plus I want to finish this project while temps outside are tolerable.

I see 2 options:

1. Run 5/8 rubber fuel line from tank to filler neck. Will need to cut the metal loop bracket off the filler neck for cleanest routing since the hole is too small for the rubber hose.

2. Use 1/2" copper water pipe (measures slightly more than 5/8 OD)

I like the copper water pipe method, but when I google if copper can be used with gasoline I find everything from it’s perfectly fine to this will destroy your engine Armageddon.

 

[b454rat]

I had something similar happen, but with the fill tube. It had pin holes in it, so took it off, cleaned it really good, used a lil sillycone to fill the holes then put about 10 coats of paint. Or just use rubber hose, easier.

 

[PlatonicSolid]

I had something similar happen, but with the fill tube. It had pin holes in it, so took it off, cleaned it really good, used a lil sillycone to fill the holes then put about 10 coats of paint. Or just use rubber hose, easier.

Yeah, I could restore the pipe, but I see that as a time consuming futile effort when a copper pipe will fit. I assume there's a reason they didn't put a full length hose there. Heck in one Youtube tank replacement video the guy replaced all his fuel lines with flexible copper lines. Granted, Youtube is just as good at providing bad advice as good (not sure why there's so many videos of clueless people doing a task for the first time). Unless someone chimes in with a good reason not to, I'm going the copper pipe route.

 

[CumminsFever]

Copper pipe should work, I can't imagine why it wouldn't. You can also replace it with a section of hose that is rated for gas/fumes.
I know, the copper pipe is drop-in, and probly what I'd do!

 

[Caman96]

You must be registered for see images attach

Mine didn’t look great either, so I forced fuel line hose over existing pipe. It was really tight, so I warmed it up good and put a coat of Vaseline on old pipe. Good as new!

 

[95burban]

Yes copper is fine, it has been used for years in old cars

 

[PlatonicSolid]

You must be registered for see images attach

Mine didn’t look great either, so I forced fuel line hose over existing pipe. It was really tight, so I warmed it up good and put a coat of Vaseline on old pipe. Good as new!

How did you get that through the bracket hole? My bracket hole is just slightly larger than the metal pipe. Yours looks very nice. I'd be concerned that my pipe would just continue corroding from the inside as I can already see little rust spots inside the pipe.

 

[Caman96]

How did you get that through the bracket hole?

This??? It slipped right through.

You must be registered for see images attach

The inside of pipe looked clean, yes it had a couple of pin holes. I sprayed it down with Klean Strip Metal Prep and then painted it with Rustoleum Rust Reformer. Plus, it’s got that coating of Vaseline! I figure it’s got at least another 10 years + on it.

 

[PlatonicSolid]

This??? It slipped right through.

You must be registered for see images attach

The inside of pipe looked clean, yes it had a couple of pin holes. I sprayed it down with Klean Strip Metal Prep and then painted it with Rustoleum Rust Reformer. Plus, it’s got that coating of Vaseline! I figure it’s got at least another 10 years + on it.

Aftermarket hole must be bigger than original. No way that's possible on mine.

 

[Caman96]

Looks like you got some room, if not, hit it with a step bit or buy a new Spectra neck.