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850 Fuel Vent Hose Repair Without Dropping Tank

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.

Forum Contributor Power Jets shows us how to re-attach the fuel tank vent hose in a 1994 850 GLT Wagon WITHOUT dropping the tank.

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.

fix 850 fuel vent - 850 Fuel Vent Hose Repair Without Dropping Tank

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Fuel vent hose repair without dropping tank

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