evap-o-rust in fuel line

[Buick35]

I'm my old v.w. I was thinking of injecting some evap-o-rust in the steel fuel line that runs through the tunnel then flushing it out.Do you think it would work or would carburetor cleaner be better? Thanks

[Frank DuVal]

Evap-o-Rust will work on rust in the line, carburetor cleaner will not. 

[3macboys]

While I get replacing the fuel line may be a pain in the .... If you are concerned about rust in the line, how compromised is the line already? Basically are you asking to spring a leak and how long is it going to last?

[Stude Light]

I would worry about contaminating the fuel line with any residual Evapo-Rust or the water flush. Evapo-Rust is water soluble so, after allowing it to linger in the brake line for a day or more to do it's job, then you would need to flush it out with water, then get all the water out of the line. It would take a lot of purging with dehumidified air/nitrogen or pulling a vacuum on the fuel line for 12 hours before I would feel comfortable that all the water is out.

Edited November 5, 2023 by Stude Light (see edit history)

[Angelfish]

Evapo Rust is magical. 

 

It's been 35 years and I still remember watching someone try to clean out an old fuel line, almost like they had some sort of mission to reuse it instead of replacing it.  It never did work.   But it taught me a lesson, and I have never regretted replacing an old fuel line. 

[Bloo]

Evaporust is indeed magical, but doesn't work so well where there is oil contamination. If I intended to do this, I would use some sort of solvent like carb cleaner first. Evaporust only works well when there is no air, and that usually means submerging the parts. Since you could plug and fill the line with evaporust, it would probably work really well. The environment needs to be above 60F or the reaction grinds to a halt. The warmer it is the faster it works. I would flush with hot water to get rid of the evaporust. Getting rid off the water is no problem, flush with denatured alcohol as if it were a brake line. Definitely check the line afterwards with a mityvac to make sure the line holds vacuum and you do not have pinholes, or so that you can fix the pinholes if you do have them.

[Buick35]

Thanks for the replies.Greg

[60FlatTop]

Most of my experience wit deterioration of tubing is with brake lines. Brake fluid has an affinity to moisture/water add absorbed water will make its way through the whole system. The corrosive water will be in the bottom on the tube. Fuel lines dry out and oxygen will work directly on the inner wall. I usually pull fresh fuel through a fuel line on a long term stored car with a hand vacuum pump to flush it out. About a pint and a half, checking what comes through is a good flush but I have pulled more if it looks and smells bad.

 

Fuel lines that have leaked generally leak from pinholes at a low point. My method of checking the tube condition works on either.

 

 

The bottom inner wall is where material loss from corrosion takes place. In this drawing the new tubing started with a thickness of 2 units. Heavier than brake fluid or gasoline water will lie on the bottom surface, slowly attacking the inner surface. It can still look fine on the external surface.

To test I gently grip the vertical sides with the jaws of a small Vice Grip. Then slowly turn the handle screw to apply light pressure, just enough to slightly distort the tube, nondestructive, about 1/32 is good. If the thickness of the bottom has decrease, less than 2 units in the example, the bottom will crack and show the beginning of a fracture. That is when replacement is due. I usually turn the Vice Grips 90 degrees and make them round again.

 

The bad ones crack open like a lobster tail.

I check the low spots and the clamp attachment points. If you have a later car with an inline canister filter they can also catch water and get pinholes at a low point.

 

I have been meaning to write this out for a while. Seems like I have an extra hour this morning.

[TTR]

14 hours ago, 3macboys said:

While I get replacing the fuel line may be a pain in the .... If you are concerned about rust in the line, how compromised is the line already? Basically are you asking to spring a leak and how long is it going to last?

Exactly.

 

Edited November 5, 2023 by TTR (see edit history)