Sealing the manifold on the top of a Vetus Fuel Tank

[Ian_Edwards]

The manifold which houses the stand pipes for the diesel engine and the heater, along with the return lines and fuel filler line on my Vetus Polypropylene diesel fuel tank is leaking.

It has been refitted with some sort of "black sealant" but when the tank is full, or when the boat heels, diesel seeps out of the joint between the tank and the manifold.

What's the best way to seal the joint?
Is it better to use a mastic type sealant, an "o" ring or something like a thin sheet of Nitrile Rubber?
Is there an internal ring which will fall out when I loosen the screws which hold it inplace?

 

[RichardS]

I had exactly the same problem last year with the 8cm diameter VDO fuel-gauge flange on top of my tank.

I got a new rubber sealing gasket from VDO who said I should not use any gasket goo but just a light smear of silicone grease and then tighten evenly ...... nipped-up tight rather than overtighened with a lever.

Your tank might have the threads tapped into a captive boss in which case you can just remove the bolts. It might have holes drilled in the tank and a tapped ring inside the tank. In this case there will be a notch somewhere in the circumference of both the entry hole and the ring which can be aligned to slide out the inner ring. One of the bolts will also usually be longer than the rest and next to the notch - this is the last one to be removed and the first to be replaced as the extra length gives you clearance to get a piece of wire round the inner ring to ensure that you do not drop it into the tank.

Once you have removed some of the bolts and loosened the last one you should be able to see whether the tank is tapped. If one of the bolts you remove is longer, replace that one and remove the rest as you have an inner ring.

Richard

 

[Tranona]

According to the description in the Vetus catalogue the seal is made by a counter flange and rubber seal that are part of the fitting. It only requires a 114 mm hole in the tank. No tapped bosses or inner ring. See p114 of catalogue.

 

[Plevier]

Is there an internal ring which will fall out when I loosen the screws which hold it inplace?

YES! Replace one screw with a long stud before removing all of them.
(Wish someone had told me that in advance.)
I had exactly the same leakage problem. I cleaned and de-dieseled all the bits inc the rubber gasket and put it back together with a smear of sealant but sorry I have forgotten what I used. (Possibly PU40)
I think it's OK but haven't filled it right up yet. Have had a good angle of heel since then with no problems.

 

[Plevier]

According to the description in the Vetus catalogue the seal is made by a counter flange and rubber seal that are part of the fitting. It only requires a 114 mm hole in the tank. No tapped bosses or inner ring. See p114 of catalogue.

ITYWF that is a later fitting. Earlier ones (mine is 2008) have a clamp ring (that falls off).

 

[pmagowan]

I think mine uses some cork as the gasket. It also has some vaseline like stuff on it. It is only tightened with minimum force and seems to work fine.

 

[Tranona]

ITYWF that is a later fitting. Earlier ones (mine is 2008) have a clamp ring (that falls off).

May well be - the photo looks the same, apart from the plate being silver rather than black in the one in the catalogue.

 

[Ian_Edwards]

The boat was built in 2007, so I guess it's the earlier design.
Just about to take it appart!

 

[prv]

I fabricated an inspection hatch for my stainless tank, and sealed it with a gasket cut from a sheet of 2 or 3mm nitrile rubber purchased from eBay. With the hatch bolted down firmly onto the rubber, the surrounding metal exhibits not a trace of diesel seepage despite regularly having a four-foot head above it in the filler pipe. I would certainly use the same technique for any other tank sealing tasks where a fitting can be clamped down onto it.

Pete

 

[Ian_Edwards]

This what it looks like.
It's obviously been hacked at sometime in the past.
No internal ring, just self tappers into the polypropylene tank.
I'm going to try a Cork gasket and see if it works.

 

[Plevier]

This what it looks like.
It's obviously been hacked at sometime in the past.
No internal ring, just self tappers into the polypropylene tank.
I'm going to try a Cork gasket and see if it works.

Someone's bodged that. I don't think ST screws into PP will be adequate.
The ring isn't lying in the bottom of the tank is it?

 

[Plevier]

Here are all the parts of it
http://www.asap-supplies.com/marine...ories/vetus-fuel-tank-connection-kit-a-ftkita

The tapped backing ring is the item with a crescent cutout in the edge to let you jiggle it in through the hole.

 

[RichardS]

This what it looks like.
It's obviously been hacked at sometime in the past.
No internal ring, just self tappers into the polypropylene tank.
I'm going to try a Cork gasket and see if it works.

You can see the notches in the tank where the notch in the inner ring slides in as in post #2.

I agree that self tappers into polypropylene will not work other than short term.

As Plevier says, the inner ring may be in the tank but even if you can fish it out you will need a new set of SS bolts and a gasket.

Might be best to see if you can buy a complete fitting kit as I did.

Richard

 

[prv]

the inner ring may be in the tank but even if you can fish it out you will need a new set of SS bolts and a gasket.

Might be best to see if you can buy a complete fitting kit as I did.

Stainless bolts are just stainless bolts - a set via eBay probably under £1.50 delivered. The gasket can easily be cut from nitrile sheet, obtainable likewise.

If the ring is in the tank and can be fished out, this will be way cheaper and probably much easier than trying to buy the specific parts.

(If the ring can't be retrieved, I'd still be looking at manufacturing a substitute, but I can see that others might prefer to buy the bits in that case.)

Pete

 

[Plevier]

Stainless bolts are just stainless bolts - a set via eBay probably under £1.50 delivered. The gasket can easily be cut from nitrile sheet, obtainable likewise.

If the ring is in the tank and can be fished out, this will be way cheaper and probably much easier than trying to buy the specific parts.

(If the ring can't be retrieved, I'd still be looking at manufacturing a substitute, but I can see that others might prefer to buy the bits in that case.)

Pete

I can't remember it now, but from the picture I posted of the full kit the "gasket" actually appears to be an O ring. This would make sense for higher contact pressure on a not perfectly flat or rigid surface i.e. the moulded plastic tank. I guess there must be a groove for it in the back of the big fitting.

As Richard s said, you need the notch in the tank as well as the circular hole to get the back flange in, despite the crescent cutout in its edge.

My leak was not actually from this big fitting, it was from the fuel gauge sender that goes through it, the picture of the kit shows a blanking cap for it. (At least I think that's where it leaked but can't be certain). That fitting has 5 screws and they are not evenly spaced but nearly so, don't know why, quite tricky to recognise the correct alignment. It has a soft rubber gasket.

The OP's photo looks as though this fuel gauge flange has been adapted for the heater fuel take off.

As this connector kit is now obsolete - replaced by the one Tranona referred to - getting OE spares might be difficult but I have found Vitesse Marine at Fareham who are Vetus distributors helpful in the past.

In this pic I see it should have soft washers under the screws for sealing too

 

[dgadee]

I looked up the yellow pages and found a gasket maker operating from home. £3 or £4 a new one cost me.

It was a flat ring, approx 1" wide.

 

[Ian_Edwards]

Yes, it's been bodged sometime before I bought the boat.
SS self tappers directly into the polypropylene.
A nitrile/cork gasket, with HYLOMAR UNIVERSAL BLUE sealant on both sides seems to have cured the leak, for now. The self tappers have a remarkably good grip on the polypropylene.
It'll be a priority winter job to make an inner ring with tapped holes and make a good long lasting job of it.
The tank was emptied and cleaned this winter, no ring was found in the bottom of the tank.
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