Tank Drain Plug

[Paulfc]

I’m dithering as to whether or not to remove the drain plug on the fuel tank. I’m painting the tank and renewing the sender gasket. My dilemma is, will I find, having removed the plug which I’m sure hasn’t budged in 50 years in order to get the last dregs of fuel out and more easily swill the tank, that I can’t get a fuel tight seal again? Any advice and guidance from those knowledgeable of this procedure will be appreciated.

Thanks

[Pete Lewis]

there are cases where the tank spout shears off before the plug decides to shift 

its easy enough to use a smear of sealer on a refit but you MUST securely support the drain tube itself do not rely on the tank to hold the force required to remove a 50 yr old plug

so  for me   thats really  leave it alone rules  that   apply 

its an easy case for ending up in tears    do be careful

Pete

[Colin Lindsay]

1 hour ago, Paulfc said:

I’m dithering as to whether or not to remove the drain plug on the fuel tank. I’m painting the tank and renewing the sender gasket. My dilemma is, will I find, having removed the plug which I’m sure hasn’t budged in 50 years in order to get the last dregs of fuel out and more easily swill the tank, that I can’t get a fuel tight seal again? Any advice and guidance from those knowledgeable of this procedure will be appreciated.

Thanks

You can still buy new plugs, and the tank probably just needs a retap. You can seal with a fibre washer, or a petrol-resistant sealer.

As Pete says, brace the drain neck and twist the plug against that, not against the tank - it'll just shear off. 

[Wagger]

My son drianed my tank about a year ago in situ after collecting all of the fuel from the pipe under the bonnet. He removed the fuel gauge sender and used a squeezy bulb for the remainder. He then cut a cork to fill the sender hole and filled the tank with mild soapy water for 48 hrs.

He then removed the tank and drained and rinsed it. Used an old hair drier inserted in the filler hole until the inside was dry. Vacuumed it out through the sender hole with tubing fitted to a vacuum cleaner.

He then re-fitted everything with all new pipes, flushed it through with a gallon of clean fuel and half filled the tank. So far, all is well.

If you try to remove the drain bung, you could end up with a leak that cannot be fixed. I would leave it alone.

[Paulfc]

Thanks all. I’ve drained it this afternoon by simply siphoning the residual fuel, nice and straight forward and avoiding the nerve racking removal of the plug. 

Wagger, that’s an interesting approach,  I may try it but minus the soapy water! What was the rational of using it? Alternatively, I may swill it with a little petrol then siphon again, vent, then use a hot air gun and vacuum out before flushing with petrol. The last step will also allow me to test a tank to filter link arrangement utilising two lengths of hose joined by a Warrior Quick Release Fuel Line Coupler as part of my plan to make future servicing and maintenance easier.

[NonMember]

14 minutes ago, Paulfc said:

I may swill it with a little petrol then siphon again, vent, then use a hot air gun and vacuum out

DON'T!!!!!

A little petrol swill + empty tank = flammable gas mixture

Flammable gas mixture + hot air gun = explosion.

[Paulfc]

Hi,

Thanks for the speedy response and words of wisdom. Certainly not intending to cause an explosion or create alarm! My intended use of the heat source will be judicious and very measured.
 

I’ll drain and then vent for a couple of days then remove any residual fuel by swabbing the tank internally via the sender hole using rags attached to a flexible claw. Then, in the open air, I’ll WARM the tank externally. My visual inspection shows it’s clearly never been anything near full in years so there’s evidence of debris internally on the roof of the tank and the upper parts of the baffles. I’m going to gently tap the tank to try a dislodge anything that’s lose and use the aforementioned claw to swab as much of the internal area as I can. I intend then to put a small amount of fuel in the tank, seal the sender orifice and other outlets ( it’s a TR6 so there are two) invert the tank and give it another good swill around and then drain and swab again. By slightly inclining the tank the fuel will drop to the lowest point, around the drain plug which I can easily access, together with any debris dislodged. I’ll siphon and swab again to get rid of what remains. I may repeat the process depending on what I find. Finally I’m intending swill and flush with clean fuel a couple of times before reassembling.

Again, thanks for your response.

[Wagger]

1 hour ago, Paulfc said:

Thanks all. I’ve drained it this afternoon by simply siphoning the residual fuel, nice and straight forward and avoiding the nerve racking removal of the plug. 

Wagger, that’s an interesting approach,  I may try it but minus the soapy water! What was the rational of using it? Alternatively, I may swill it with a little petrol then siphon again, vent, then use a hot air gun and vacuum out before flushing with petrol. The last step will also allow me to test a tank to filter link arrangement utilising two lengths of hose joined by a Warrior Quick Release Fuel Line Coupler as part of my plan to make future servicing and maintenance easier.

He used water in case a leak appeared at my advice. The soap makes it search a bit more. I have brazed and soldered seams on tanks about 97% filled with water. They don't explode. An old 8th army maintenance guy showed me how. He went from Africa through Italy all the way to Berlin. He was the last vehicle in the convoy keeping all those in front of him moving repairing or smashing everything on the way. I still use his ingenious 'Bodges' in an emergency.

Do not use heat on an empty tank unless it has had water in it for 24 hrs. That was his advice.

[Paulfc]

Thank you!

[Unkel Kunkel]

Swilling 1-2 litres of acetone  is  good to remove the “varnish” type stuff that binds all manner of rust and debris in the bottom of tank.

(Cheapest source for this is a builders merchant that sells fibre glass  roofing material)

As mentioned beware hot air gun -I posted a picture last year of a tank that exploded when someone did this.They significant injuries - and a  destroyed tank.

Filling as much of the tank with water as possible up to the level brazing / soldering / welding as  per Wagger describes is good practice.

- Steam cleaning for some hours helps cleaning and makes things a lot  safer if any repairs are to follow.

If you have a wall paper steam stripper, then you can have an effective steam cleaner -  take the end plate off and put the pipe into the tank.Keep checking and topping up the water level.

It works well - only drawback -care needed as the whole tank gets a lot  hotter  than you  might expect!

[GrahamB]

The advantage of filling the tank with water is that it displaces all of the flammable vapours. Also, as the residual fuel floats on top of the water, if the tank is overfilled the fuel flows out first.  I tried to clean out a Spitfire petrol tank via the sender orifice and found it very difficult to reach into the far covers to remove all the residues.

Many years ago, I worked in the HSE laboratories.  There was a continuing series of reports concerning people welding  and causing explosions .  The heat from the torch vaporised flammable deposits, such as heavy oils and lubricants within the vessel, forming an explosive mixture that ignited with disastrous results.

[Badwolf]

Yes, I was taught the 'fill with water' trick when I was working on my old Hillman Husky in to 70s. Fill with sharp gravel and shake, don't stir (although I did hear of someone who strapped a tank with gravel to the front of a slow turning cement mixer for a couple of hours) to remove rust etc, empty out and then use the internal sealing paint of your choice or check for leaks and refit.