How to: Fuel Vapor Line Repair (EVAP)

[JSWarrell]

So this is more of a "How I did it" rather than a How-to, but I decided to fully document my repair as I found no info on this before. I don't know how helpful this will be for 91-92 owners, but I'm guessing the only real difference in the systems is that the vapor canister is in a slightly different location. This repair was done on a 1994 model.

Ever since I bought my Explorer I would smell gas after a long trip. Upon one the many discoveries I make while performing other services and repairs to the truck, I found a very rusty 1/4" line running parallel to the fuel lines, with many holes in it. That is the fuel vapor line.
My state and county requires that this vehicle passes both safety and emissions inspection. Somehow it still passes emissions with this problem, but I think it's because all they care about at the shop I go to is that the check engine light is off, the fuel cap doesn't leak, and it passes the dyno pipe sniffer test. EEC-IV doesn't monitor EVAP performance, only the canister purge circuit, so the check engine light doesn't come on like it would for an OBDII vehicle.

Anyway, I put this task off because I knew it would take me longer than a day to do, including any unexpected problems I might encounter along the way. In reality, this shouldn't take longer than a day to do, but I get very opportunistic and like to address things while I have something apart that I wouldn't be able to get to otherwise.

So....pictures.

Day 1

These three along the frame are the fuel lines. The pressure and return fuel lines are stainless steel and don't have this problem. The vapor line appears to be plain old steel. I imagine at one point it was zinc plated or something like that, but not anymore.

Dropping the tank...I made sure I was on E with only a couple gallons left in the tank, pretty much just enough to run to the cheapest station in my town.
This skid plate has to come off first. There's three bolts in the front:

One bolt in the frame rail just above the leaf spring. This one was a pain even with wobble extensions on my impact wrench. The parking brake cable runs through this space so you have to hold that out of the way as well:

And one towards the rear beside the driveshaft:

(These are all 13mm)

I had a jack with a piece of 4x4 lumber ready to catch it. The plate is a bit on the heavy side so having that thing drop down can be a bit surprising if you're in the way.

The front of the skid plate will pivot and can then be slid out by the center tab.

I later found that the corner piece of heat shield was removable and needed to be removed so that the front strap could be completely undone. I neglected to PB blast the two studs along the rearward edge and ended up breaking one of them.

A little bit of wiggling and tilting and it came right off. I'll be wire brushing this and spraying it with some rust converter.

All that's left holding the tank is a single strap right in the center. I had a jack ready to catch it and undid the strap.

Wondering why it was getting snagged, I forgot about the filler neck and vent hose. A 5/16 driver with some extensions and a large pick and they popped right off.

And there's the lines connecting to the tank. The small one making the "S' curve is the vapor hose, connected to the hard line along the frame. I also took this opportunity to remove the brake line that was bypassed by a previous owner and just left there. Inspectors didn't pick up on that either, but I guess they aren't that stupid and noticed the new line alongside it.

More of the damage. I think I can safely assume these lines were never touched, judging by the green "CAUTION: FUEL" tape wrapped around it in several spots.

Now for the removal of the line: A self-tapping bolt in the front wheel well on the top of the frame, behind the spring and shock mount (at one point it was probably 10mm, it's now a 3/8)

A 13mm nut holding the inner frame bracket. This one is in the same proximity as the previous one. There's also an ABS deceleration sensor located in this spot, which should be unplugged or removed to make it easier to pull the fuel line bracket out of its place. Once again, I didn't use my penetrating oil because I'm an idiot and broke the stud, but thankfully it was halfway off so I still had some usable threads.

At this point it became apparent that the entire front fuel line assembly had to be removed as a unit. This includes disconnecting the pressure and return lines, and getting the fuel filter out of the way.

A simple disconnect of the lines from the engine side is normally all that is involved at this point, but in my case, those connections were seized, and the cheap plastic quick-connect tools were completely useless.

Onto plan B: Unbolting the fuel lines from the fuel rail and dragging them out along with the rest of the line.

Of course, the return line is buried under the upper intake plenum, so that had to come off too. I've had this off many times, so I begrudgingly did it again knowing I'd make short work out of it. Whatever.

(These two connections are 17 and 19mm)

Aaaaand, with some more finagling, there it is! One front fuel line assembly. The rear vapor line thankfully doesn't require as much effort to remove. Just a few annoying clips which can be carefully pried open and it'll slide right out from behind the cross members in the frame.

 

[JSWarrell]

(20 image limit, this is part 2)

These lines are held together with these clamps that are pinched shut with a locking tab. A hammer and chisel opens them right up. This one is riveted to the bracket that mounts to the frame.

So, what am I replacing this vapor line with?

1/4" Aluminum tubing. Easy to work with and hopefully a bit more corrosion resistant than the steel that was used prior. There's probably something better I could have used, (like...you know...stainless steel?) but this seemed like the most practical low-cost option while retaining the stock setup. I bought this off of JEGS' Ebay store (Part# 365210). Came out to about $25 including shipping, and I ended up having a lot left over after this project.

I could probably just slide the rubber hoses directly onto the ends of the line, but I wanted a bit more security like the stock line had, so I busted out my worthless brake line flaring tool (Harbor Freight again, big surprise) and ran the die halfway down to give it a rolled edge. I don't remember where I saw this idea, but it worked like a charm. A little bit of 800 grit sandpaper got rid of the burrs left on the sides.

This stuff is so easy to shape. I was able to make the line nearly identical using only the contour of my thumb.

And the front line. Somehow I perfectly guessed the length when I went to cut it.

I decided at this point to call it a night and spent the rest of the evening wire brushing and spraying the area of the frame where the fuel tank sits, along with any pieces I took off. I used Rustoleum Rust Reformer. Once I fix the rest of my fluid leaks, I'll do the rest of the underside the same way and maybe hit it with RP-342.

Day 2

In goes the new line! It took me a bit of trial and error to remember which way this line was supposed to sit in the clips. The old line helped me out by leaving rust marks behind. I had to manipulate a couple of the bends along the way as well.

And the front, with the canister hose hooked up. Before anyone says it, yes my brake lines look pretty bad and may require attention in the near future.

I forgot to take a picture of the front bracket all cleaned up. I made the decision to rivet it back together the same way it was done from the factory. Hopefully I won't have to work on this again for a long time, and this move won't come back to bite me.

And here is the hose from the tank hooked up to the new line.

Installation at this point is pretty much the reverse of how it came out. The front strap needs to be put back into position since it runs over the top of the tank. The rear of the fuel tank needs to come up first before the front does, then it can just slide into its front perch on the frame. Once the strap is fastened in, it'll stay in place until the skid plate goes back on.

I doubt that this heat shield would rattle that much with that top nut missing, but as reassurance I cleaned up the spot with some brake cleaner and stuck some foam tape to it.

And there it is, all buttoned up.

After that, I ran it, checked the fuel system for leaks, took it out to the gas station, and checked the filler neck for leaks as I filled up. All's good so far. Took it on a 25 mile run that included interstate driving and then back roads through town until I got home.

After all of that work, the fuel smell is completely gone. Mission accomplished!

Oh yeah, and I thought I would add a picture of all the dirt and rust that fell off this thing while I did this.

And yes, there was a peanut lodged in there up in the frame. Whatever didn't end up on the ground ended up on me. It goes without saying that safety glasses are strongly recommended for this project, and even then I still got a speck or two in my eyes.

Anyway, thanks for looking, and I hope this helps out anyone who has this problem or one like it, and even offers a bit of encouragement given the daunting task of dropping a fuel tank. It's not that bad as long as you don't have a full tank.

 

[Arne13]

Nice write up. Thanks for taking the time to post it. Arne.