OK, been having problems with my fuel tank in the crewcab. Every morning and afternoon, theres been a strong smell of petrol in the cab for a few weeks. After a quick spin with the windows open, the smell goes away.

I fitted a new fuel cap from C&C a couple of weeks ago thinking the old one was leaking. However, this has made no difference.

Yesterday, after leaving it out in the sun during our club dinner I found a big patch of fuel under the bus when it was time to head home so finally today I drained the tank and pulled it out.

The seams are fine all the way round as I left a couple of litres in the tank and have had it stood on all 4 sides during today with no visible leaks/pools of fuel.

When i took the tank out, only the top of the tank has fuel stains apart from one corner where the fuel has dripped over the lip onto the floor.

I'm guessing the problem is there is no breather pipe/hole so the fuel vapours are expanding in the warmth down here and forcing the fuel out through the sender seal.

The new fuel cap has a new cork seal but appears to be pretty much airtight as when I was draining the tank I noticed the flow of fuel was slowing down and when I opened the fuel cap, the flow increased.

So, thats the explanation but what can I do to stop the problem?

I find it crazy that there is no breather pipe. I've read on here that the original VW filler caps were breathable! If thats the case.... how? And if so, i'd really be no better off as the fumes would still make there way into the cab under the back seat.

I'm a bit confused to say the least

Any ideas anyone?

Please

i had a strong smell of fuel in our crew cab
every so often , what i ended up doing was
i took the two panels out from behind
the seat then stuck a strip of sticky foam to them,
around the edge to make a seal
put them back on and have not smelt it since
(i checked the tank for a leak but could not
find one)
i thought that most caps had a small hole in them
to aid flow/ stop pressure build up (but i could be
wrong on this)
good luck
giles

Yeah, caps have a very small hole in them to vent the tank.

You could weld a breather port onto your tank to vent that way, if you have the facilities to do that.

giles7368 wrote:i had a strong smell of fuel in our crew cab
every so often , what i ended up doing was
i took the two panels out from behind
the seat then stuck a strip of sticky foam to them,
around the edge to make a seal
put them back on and have not smelt it since
(i checked the tank for a leak but could not
find one)
i thought that most caps had a small hole in them
to aid flow/ stop pressure build up (but i could be
wrong on this)
good luck
giles

basically, you did what ostriches do. they hide their heads and the threat disappears.

sometimes what happens is when you park with the fuel filler side towards the curb, fuel creeps out the cap, runs down the neck and drips under the bus. other times, it's the fuel tap or the fuel line right where it comes out of the tap. there tends to be a tight curve there. also check where the fuel line enters the carb. that spot right there is the numero UNO cause of engine fires. any time you have a fuel leak, you have a serious problem.

i hope you all carry a fire extinguisher in your vehicles, preferably a halon bottle.

I had a similar problem with my crew cab. When I took the panels off to look at the fuel tank I discovered the tank was wrapped in an old duvet and strapped in place with an old leather trouser belt. The tank didn't have a leak, but the duvet soaked up the fuel that (presumably) spilt from the nozzle as it went into/came out of the tank and ran into the closed off area under the bed and behind the gas tank closing panels.

There's a lot of fersh air there now waiting for new metal to be added...

Well, I took the tank out this week to have a gander.

The first thing I noticed was the fuel stain all over the top of the tank down to just above the seam.

I left a couple of litres of fuel in the tank and left it on its various sides for about an hour each side. There was no sign of leakage around the seam anywhere.

I removed the sender unit and was surprised to discover the mating surface that sits on top of the tank was badly distorted into a wavey pattern. Is this normal or should it be perfectly flat?

Looking at the tank staining and the sender unit and knowing the cap that came on the tank was non original and non breathing I've come to the conclusion that my problem has been vapour expansion in the tank being unable to escape in the warm weather down here and forcing its way out through the sender unit seal (very old and brittle)

As I needed to get the bus down to the storage facility today before flying back to UK for xmas I had to put it all back together using a new homemade sender seal and plenty of silicon sealant. I also drilled a hole in the new C&C fuel cap (btw, C&C say their replacement caps do breathe if used with their cork seal. I can tell you from experience that if you really crank on the fuel cap, they don't breathe at all.......be gentle )

Anyway, after filling the tank back up and driving for 10 mins the smell of fuel in the cab is as bad as ever. This is more than likely due to the hole in the fuel cap (remember in a crewcab, the tank is directly behind the cab and not in the engine bay so fumes can get into the cab quite easily under the back seat.................and yes, i did put new seals on the partition panels before refitting them )

However, I also think the sender unit is goosed and letting fumes/fuel out, despite my best attempts at sealing it.

Stupid question before I go any further ...............In a crewcab, should you be able to see into the fuel tank space through the filler flap or should that be completely sealed from the outside. ie,the fuel filler neck has the neck seal around it and all in situ but I can see around the metal support plate into the space where the tank sits! Is this normal or do i have a panel or2 missing? I really should have taken a piccy but like a dumbass, I plain forgot

If it is normal, I find it strange that VW would design something so petrol fumes would vent directly into the space occupied by the tank.

At the moment, I'm leaning towards replacing the whole lot with a Fairbank and Craven ali tank with built in breather and a pipe leading well away from the cab, new sender and non breathing filler cap. Has anyone have any experience with the fairbank and craven tanks? Are they built to a standard etc etc.

All advice welcome. I use my crewie everyday and cart my baby daughter around in it to kindergarten etc etc so it needs to be safe

Re your stupid question - mine is the same as yours - open the gas tank flap and peer in and you'll see the tank. You don't have any missing panels. Ventialtion wise, the panel behind the fuel tank is slotted, so there's plenty of ventilation back into the engine bay. I have plenty of photo's but am struggling to upload them at the mo. Never taken a sender unit out of the tank, so don't know if the mating surface on the tank should be wavy or not. Re using silicon as a sealant, I've heard of a case where the silicon was applied a bit too liberally and globules of silicon kelp blocking the fuel line.....took the bloke ages to figure it out...

(remember in a crewcab, the tank is directly behind the cab and not in the engine bay so fumes can get into the cab quite easily under the back seat.................and yes, i did put new seals on the partition panels before refitting them )

Remember in everthing else the heaters draw air from the around the tank area.
When I first got my Samba the non original fuel tank had a couple of holes crudley drilled in it and the tank showed signs that it had been sucked in. When I went around a left hand corner with the tank quite full you would get a strong smell of petrol. What I did was weld up the holes in the cap ( there was two layers of metal) and redrilled them with a tiny drill so that the two holes didnt line up.

As I needed to get the bus down to the storage facility today before flying back to UK for xmas I had to put it all back together using a new homemade sender seal and plenty of silicon sealant. I also drilled a hole in the new C&C fuel cap (btw, C&C say their replacement caps do breathe if used with their cork seal. I can tell you from experience that if you really crank on the fuel cap, they don't breathe at all.......be gentle )

Just how big a hole did you drill?
I would first get a proper vw fuel cap. And make sure that the sender unit is well sealed. Mike

i have not got a seal at the top of the neck
near the cap either
i can see all the way into the tank.
giles

Eternal Optimist wrote:Re your stupid question - mine is the same as yours - open the gas tank flap and peer in and you'll see the tank. You don't have any missing panels. Ventialtion wise, the panel behind the fuel tank is slotted, so there's plenty of ventilation back into the engine bay. I have plenty of photo's but am struggling to upload them at the mo. Never taken a sender unit out of the tank, so don't know if the mating surface on the tank should be wavy or not. Re using silicon as a sealant, I've heard of a case where the silicon was applied a bit too liberally and globules of silicon kelp blocking the fuel line.....took the bloke ages to figure it out...

Yeah, I was careful with the silicon

Ref the 'panel behind the fuel tank is slotted', which panel are you talking about? The engine bay bulkhead panel?

Having spent most of last week with my head in the fuel tank compartment, I can safely say there is no slotted panel anywhere on my crewie apart from the rear corners which vent directly to the engine bay for cooling. What year is yours?

Brooksy, Yeah, I used a 1mm drill bit for the holes. I'll be ordering a new sender today ready for fitting when I get back to Spain and hopefully will find a genuine fuel cap on the web soon. Funnily enough, my tank didn't show any signs of compression or expansion damage, just the sender unit.

Thanks for the replies everyone

I can see this is going to be a case of experimentation

Mine's a 66 model year. I've emailed you three photo's, let me know if they don;t come through
Cheers

Eternal Optimist wrote:Mine's a 66 model year. I've emailed you three photo's, let me know if they don;t come through
Cheers

Thanks Nige. They came through fine.

It must be a later model thing as my '65 which I sneakingly believe is a '64 due to its small rear window has a solid engine bay bulkhead panel.



The other explanation could be that mine used to be a fire truck so that panel could have been solid for safety reasons. But i don't really know.

That slotted panel would sure help the cooling fan in sucking fumes out of the fuel tank compartment though

Good luck with the rest of the restoration Its something that I think mine will be needing sooner rather than later having now seen the repairs to the sills from the inside...............it looks like rivets and filler and the number of floor repair patches done using sheet metal

Do you have a thread going about the resto?

Reckon you're right about yours being a 64 if it's got a small window - I think yours has vents in the rear quarters. 66 on had the vents over the wheel arch and a plain rear quarter. Mine's a South African truck, so it had the vent ducts mounted on the gates. I'm ditching those in favour of the vents over the wheel arches. One NOS panel for the NS and an Autokraft panel for the OS. (Unless I can find NOS)

I have got a resto thread going.....not upated it since the Spring. Only significant progress since then is buying (yet) more panels at Vanfest and a fabulous new welder.

I think I'll put up a photo of the new welder...and some of the panels...and the practice welds that make me look like a pro...in an attempt to shame myself into getting started again.

[url] http://www.ssvc.ukshells.co.uk/phpbb/vi ... t=crew+cab[/url]

Getting frustrated now....can't seem to put a photo up or a link up. What am I doing wrong?

When your in photo bucket copy and paste the IMG code.