Laparoscopic fuel vent hose repair without dropping tank

[Power Jets]

1994 850 GLT Wagon.

I've read excellent posts on diagnosing fuel tank vent line leaks (gas smell if you fill beyond 14 gallons). My case was typical, and having removed the fuel pump and fuel sensor plates in the trunk, with eyeball very close to the deck I confirmed that there was indeed a crack at the fuel tank end of the vent hose just where it meets the blue tank connector.

Problem was what to do next. Dropping the tank to remove the hose is well documented on these boards, but it also seems like a considerable struggle, especially to reattach it, plus you need a floor jack, cinder block, nerves of steel, big fire extinguisher etc.. I did read a cryptic comment from a contributor claiming that they could replace the hose in 95% of cases without dropping the tank, but without further explanation (apologies to the savant who wrote that, I've looked hard but can't relocate your post... anyway, big time kudos to you!).

So I decided to give it a try with the car unjacked. The issue at both ends of the hose is access to the hose clamp nuts... predictably these are aligned for top access with the fuel tank dropped. With the fuel tank in place I couldn't easily get a wrench on either end... the hose clamps weren't positioned with this in mind.

The vent line end was easily solved in classic style... I used a screwdriver blade from the underside to wrench the screw drive cover off the hose clip, destructively. 30 seconds and done.

The tank end was more complex. My initial thought was to drill a connected row of holes in the hose clamp itself and break it apart.... easy drill access through the fuel gauge port. After the first hole I decided this was a bad plan... difficult to avoid drilling through the rubber and damaging the blue plastic fitting itself... plus the faint whiff of gasoline didn't seem drill-friendly.

Instead I gingerly drilled a 1/8" diameter hole in the chassis just about the hose pipe... a photo will show my first attempt (a miss) and the second, which was ideal. Then it was a simple matter to unscrew the hose clamp, through the hole, and gently prise the pipe off.

Replacing the pipe was trickier because I mistakenly chose to install first at the tank end with the pipe in-situ. DO NOT DO THIS.

The learning is to connect the pipe (non-tank) end first with the end sticking out from the fuel pump access port.... then it is easy enough to twist it on to the pipe. Done the other way it is difficult.... space is tight. I used petroleum jelly and also cut a conical taper on the inside of the pipe so it slipped on more easily and eventually succeeded. The hose clamp seems like it would be impossible to tighten in the constricted space, but with the right alignment and a socket wrench and universal joint it was easy. Once the vent end is attached, then thread the hose through to the tank connector.

The tank end was a slight fiddle until I figured it. There is another black/blue striped hose in that space, plus the tank sensor wire. The trick is to push both these behind the blue connector or they will interfere with pushing the vent hose onto the fitting. Make sure the hose clamp is arranged so the tightening end is at the low side of the pipe, pointing out of the vent hole... simple to tighten, and one day to remove. To trim it out I found a couple of screws to tap into the chassis drill holes and restore that Swedish designed-in look.

So, vent line replaced, no tank drop. Knowing what I now know, I'd estimate a 20 minute job once the cover plates are removed.

I'm glad finally to pay back to Saint Matthew... and once again kudos to the not yet identified maestro who inspired the effort.

I have some photos but no idea how to post them... I can email if desired.

drill hole location.jpg

pipe location.jpg

vent end removal.jpg

finished.JPG

[jblackburn]

That's awesome. Thanks for the detailed description...sounds like your method sure beats doing it the tank-drop way!

If you want to upload the pictures, just hit "post reply" and click "upload attachment" under the text window at the bottom of the page. Browse to your file, and click "add file" for each one.

If you'd rather, I can upload them too. Just email them to me at jablackburn (at) gmail.com

[jblackburn]

Pictures uploaded...thanks!

[cn90]

Fascinating and very smart trick to avoid dropping the gas tank!

A tip to "fish in" new hose: attach a barb fitting or something similar to OLD hose and new Hose and fish new hose through.

[boosted5cyl]

[mercuric]

Awesome! Haven't experienced this yet myself, but wonderful trick here. I haven't had to muck with a gas tank in a long time and hope I never have to again. Thanks for sharing, one for the repair list no doubt.

[oldschoolvolvo]

I will say tho, that dropping the tank isn't really that hard, but good job finding an alternate way!

[jadnhm]

I have the same problem (gasoline smell, likely a vent hose) but I have the early AWD setup. I would love to find a way to do a similar procedure for my car - it's even more work to drop the tank as the entire rear end suspension and drivetrain has to come down first.

I've done my best to locate a busted hose but I can't see anything split, despite some pretty serious inspections. I would love to get one of those video scope inspection tools....

[Power Jets]

I suspect you could pressure the fuel filler and listen for the leak... good luck!

[rspi]

I have this leak on a 850 sedan. Do I need to get the hose from Volvo? Can some stock fuel or large vacuum hose work (what size hose)?