Fuel level sender seal.

[Al Campbell]

The seal on my 1983 GTV6 is leaking.

I've been chasing petrol smell in car for weeks. I've replaced all the rubber hosing around the tank and checked the vapour tank for leaks. Filler coupling doesn't leak after filling as far as I can tell.

Went for a drive in the hills with a nearly full tank last night and discovered petrol leaking out around the sender on the top of the tank. I have already had a couple of goes at tightening all the screws and the seal looks intact but obviously isn't doing its job.

Are those rubber rings still available or should I use a large bead of gasket goo or some other sealant?

Or does anyone know of a source of sheets of fuel-proof rubber, from which I could craft a new seal?

Thanks,
AL.

[Barry Edmunds]

Al
Wh are you located?
If the seal on your sender unt is the same as the 105's I have a couple of spares
Barry
0405 383 431

[minipete]

What you need is Nitrile Rubber.  Used for making seals and O rings.

Clark Rubber list it on their site.

Pete

[tpalfa]

available from here;-

http://www.international-auto.com/index.cfm?fa=p&pid=2509&posid=1441849

http://www.international-auto.com/index.cfm?fa=p&pid=2546&posid=907748

[Al Campbell]

The sender seal is 75 mm o/d and 50mm i/d with 6 holes on 62mm diam, needs to be at least 4mm thick.

I'll have a go at making one from Nitrile from Clark Rubber as I also need replacements seal rings for the caps on the clutch and brake master cylinders. I can put a lump of the stuff in some brake fluid and see if that fluid dissolves it first.

Thanks for the help Barry, Pete & TP.
AL.

[alanm]

I have used nitrile from Clark rubber to make a new seal for the fuel filler cap on my GTV6.
The seal has started to swell up a little – effected by the petrol.
My advice would be to get nitrile rubber, but also ask about a rubber/cork compound that is more resistant to petrol than nitrile.
I believe that Clark Rubber can order it in.

In my case, the cap seal is not the problem, maybe its a collapsed baffle that is allowing too much petrol to splash up the filler neck???

Alan.

[Al Campbell]

Interesting Alan.

I did a little bit of research. Nitrile is supposed to be good for petrol, but not brake fluid. Viton (also available at Clark Rubber) is supposed to be good with petrol and ok with brake fluid. I'll get some of that and test it in both fluids. Not sure how long it'll take to swell. I'll see what they say about the nitrile/cork.

Maybe an order to IAP in America...

AL.

[minipete]

Interesting that the Clark stuff swells with fuel.

I haven't bought any from them.  I got some offcuts many years ago from somewhare I can't remember (not Clarks) and used it many times, that stuff doesn't swell.  I figured I would get the next lot from Clarks but maybe I need to look further afield.

Thanks for the info.

Pete

[Al Campbell]

Bit of an adventure.

Clark Rubber had a printed pamphlet at their store with different information than their web site. Suggested neoprene was fuel-proof and nitrile wasn't. They didn't have any nitrile thick enough, so I brought some 4.5 mm neoprene. Put a square in some petrol overnight. Swelled up and the petrol was turning black too. Shame, as I made and installed a new seal of that stuff.

Went back and got some of the thin nitrile, planning two layers. That's been soaking in the jar of petrol  since Sunday 1pm. Looked ok Sunday evening. I'll see what it looks like tonight.

The original seal looks fine but doesn't seal very well at all. Could be the design. It's a large flat ring with two small annular ridges near each edge and a ridge around each screw hole. Same on both sides. You can just make it out in the first link to IAP of tpafla's, above. It looks like the ridges are supposed to make the gas tight seal.  I imagine if the moulding isn't real good or the two surfaces aren't flat then it won't seal.

The soluble neoprene seal that is in there at the moment is working though. It's the first time in my 3 years on ownership that I haven't have a cabin full of petrol fumes in warm weather.

Will  order some viton as some sources say it's transmission fluid proof and I still need seals for my clutch and brake reservoirs.

AL.

[Al Campbell]

Well after 30 hours in petrol, no change to the Nitrile. Car now has Nitrile Seal.

The Neoprene seal I installed 3 days ago had already started to disintegrate. Hope nothing got into the fuel into the tank. Will fill the tank to dilute anything just in case,  Then change filter down the track.

Boy the pressure that builds up in the tank is a worry. Should have heard the whistle as the pressure all came out through a 4mm screw hole. Need to check that the oil vapour line from the engine isn't blocked.

AL

[Jekyll and Hyde]

Boy the pressure that builds up in the tank is a worry. Should have heard the whistle as the pressure all came out through a 4mm screw hole. Need to check that the oil vapour line from the engine isn't blocked.

Yep.  Probably got something to do with the original seal leaking.  The breathing systems on Alfetta fuel tanks are notorious for blocking and causing excess pressure.  Many a 4 cyl fuel tank has developed a small split at the bottom from the tank expanding and contracting due to a blocked breather.

[tpalfa]

After getting the holes in my fuel tank welded up I replaced all the tubing and cleaned the valves on my GTV6 breather. Now my car doesn't stink of petrol fumes. Today it was stinking hot and I was working on some rust in the right front fender/wheel arch and smelt some fumes. I'm guessing the breather is now working as advertised and vented the fumes into the engine. Whereas before the fumes were vented into the cabin.

Still lots of pressure in the tank on hot days but the one way valve in the breather seems to be working ok so I'm guessing this is normal.

While I was pressure testing my tank and fittings I noticed some leakage around one of the screw holes on the sender. I cleaned up the surfaces, seal and screws and it stopped the leak.

I still can't believe the state of the fittings on my tank, one (or more) mechanic had decided that their coarsest rasp was the best tool to use to clean the surfaces - they then used fibre rather than copper washers - I'm guessing to try and make the rough surfaces fuel tight. Shame the fibre washers aren't fuel proof.

[Al Campbell]

That "Fuel Vapour venting valve" is a little controversial about whether it lets excess pressure out of the tank or lets air in if there is too much vacuum in the tank.

I thought it was strange that if the valve was to let excess pressure out it would be odd to vent it straight in to the cabin – wouldn't imagine that it would pass ADR rules either. I had brought enough tubing to let it out through the rear side vents.

I took the thing off to clean and check and couldn't blow through it at all – thought it was good and blocked until I tried it in the other direction. Works fine – if it was set up to let air in to the tank. Matches the picture in the manual to let the air in too.

Lots of posts about which way it should go. Later models may vent excess pressure out through a charcoal canister in the engine bay. Have read about a small hole in the canister getting blocked.

Thought I saw some more factory documentation stating it let air in – I'll try and find it again.

Doesn't make sense though given the excessive pressure. Makes you worry about the fate of the 27 year old plastic vapour collection tank as well as the steel  fuel tank. Very tempted to turn the valve around. Change it with the seasons? Or fit 2 – one each way?

Test for tonight is to pull the vapour line off at the separator on the engine.

AL.

[tpalfa]

Its meant to breathe. If the pressure is too low, air is allowed in, and if the pressure is too high fumes are vented to the engine.

there are two valves on the breather:-

the little plastic one that sits on top of the parcel shelf which lets air into the system

And the larger metal one which is tucked away under the parcel shelf, that lets excess pressure vent to the engine. Its a one way valve and its connected to the engine via a plastic tube that runs along the side of the driver's seat, through the firewall and to the vapour separator on the engine.

[Al Campbell]

That's my understanding too. The check valve is missing on my car. I replaced the rubber tubing all the way to the hard plastic tubing where it disappears inside the chassis. Even had a look in there with a mirror. There  was a break in the rubber tubing joined up with a short length of metal brake pipe half way along the shelf. So I suspect the valve had been removed.

I think there is a blockage in the hard tubing section of the vapour line. By the time I got a chance to pull the pipe off at the oil separator on the engine, the air was cool and there wasn't any pressure left  in the tank. I've already replaced the rubber tubing in the engine bay, so it's not in that bit. Cleaned the separator too.

I'll pull the hatch cover up again over the tank and try blowing air back to the engine. Then try some fine wire shoved down the pipe. Picked up some more de-greaser on the weekend.

AL.