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MG TD TF 1500 - Draining Fuel Tank

Any precautions to take when draining the fuel tank. I have about 5 gallons of old fuel I must get rid of. I don't see any washers or gaskets listed in the Moss catalog, so I'm unsure if I need to replace anything once the drain plug is reinstalled.
L Karpman

There is a washer on the drain plug. I didn't re-fit the drain plug. I fitted a drain tap to make life easier if I ever have to drain the tank again.
Regards
Declan


D Burns

Easier to disconnect the fuel line at the carb and use the electric fuel pump to pump it empty. MUCH less messy! The less you disturb the possible places for fuel to leak the better!

Tom Lange
MGT Repair
t lange

Thanks Tom. I thought of that, but was afraid of overheating the pump. How long approx. to drain 5 gallons?
L Karpman

Not to hijack the thread but I'm wondering what is the consensus for disposing of such drained fuel?
Ed
efh Haskell

I've done this twice, for 3 to 5 gallons. I've given it a lot of thought, as I have great fear of fuel fires.
I used a self priming siphon, available at any auto parts store. To get it to the bottom of the tank, I fastened the hose to my wood fuelguage dipstick. Drew the fuel off into a gas can.
Only then did I drain the final few ounces out by removong the drain plug.

Tom
'54 TF
T Norby

Like Declan, I installed a drain with cutoff. Make sure you do this outside, away from anything, with a fire extingisher at the ready! Larry
Larry Brown

I'd still like to know how long its will take to drain 5 gals. of fuel using the fuel pump, and how long I can run the pump without resting so I don't burn it up. Anyone?
L Karpman

Larry - "was afraid of overheating the pump."

The pump shouldn't over heat as the fuel flowing through it will act as a coolant. You should remove one of the primary wires from the ignition coil when doing this as it will over heat and probably be damaged (along with the points if they are closed) by leaving power to them for long periods of time.

"How long approx. to drain 5 gallons"
At approx 1 pint per minute, it would take about 40 minutes. If you attach a flexible line to the output of the pump and run it down to a gas can on the ground, you can use the pump to start the fuel flow and it should continue to siphon the fuel out even after turning the ignition off. Cheers - Dave
D W DuBois

Thanks Dave!

Now I have two alternatives. Use the fuel pump or use a siphon pump in the tank. I'm concerned using the fuel pump might draw crud from the bottom of the tank through the filters and fuel lines, whereas the siphon pump would not. Are my concerns valid?
L Karpman

"Not to hijack the thread but I'm wondering what is the consensus for disposing of such drained fuel?"

Since I have an old John Deere tractor that will run on about anything, I mix it there and thus recover it.

Lacking such an easy disposal site I suggest that you can mix a gallon or so at a time in your regular driver with little or no adverse effect. I would run it through a filter while letting it pump/siphon out of the tank.

If it's more than a few years old perhaps the above is not an option and you might seek out a local disposal agency. I have one locally who will accept gasoline. I have never brought them gas but have disposed of antifreeze there.
JE Carroll

LK
Either way, you want to get the "bottom crud" out of there.

Tom
T Norby

I siphoned my tank using the old fashioned suck-on-the-tube to start the flow method and it worked fine. I've done it so many times over the years that I never get the gas (or other fluids) in my mouth... there's a trick to it (and using a clear hose helps in that regard). I don't necessarily recommend this method, but if you've never done it before and want to try, practice with water until you're good at it... it's easy once you get the hang of it. Drained my full tank into several 5-gallon containers that way, clamping the hose between container switches to preserve the siphon. Did it outside in the fresh air and with the battery disconnected to eliminate any sparks. Then I removed the drain plug with a pan underneath to get the last pint out. Didn't spill a drop.

As to what to do with the old gas, I simply add a small bit to each new full tank of gas in my daily runner car until it's gone. Your car will never suffer from that small diluted amount and you will minimize the impact on the environment (compared with pitching it). Of course I do filter it first - I use a Coleman Fuel funnel - they have a very fine mesh screen inside and work great.
Kevin McLemore

Don't forget that the outlet fittings are a bit above the bottom of the tank. There's still a good bit of fuel left after it stops draining out. It takes a good bit of effort to remove the last of the fuel without removing the tank. Bud
Bud Krueger

I am curious about the shut off drain that you folks used in place of the plug. I assume it's brass and I would like to know where you purchased it and if you had to re-tap the drain plug to accommodate the shut off valve?
R C Flowers

I use my old fuel in my Briggs and Stratton powered lawn mower. It runs fine on it.
Jim Merz

Well, the tank is drained. I was unable to siphon with the miserable siphon pump I had, so I used the fuel pump. I let it pump for 2 minutes at a time, then rested it, and then pumped again. The pump never really got too warm. I also disconnected the LT lead to the coil.

I was surprised how quickly 5 gals pumped out. It seemed like a trickle looking at it, but I guess not. The TD is running better than ever right now, so I put good fuel from my 2.5 gal can in it and I took it down the road to the closest gas station and put in 6 gals of mid grade fuel and about 6-7 oz of fresh Seafoam. The car ran beautifully for the short round trip, and I'm keeping my fingers crossed it stays that way now that I am able to drive it again.

The car idles fine, runs fine, and the dieseling has stopped completely. I only hope that it remains that way during normal driving. I'd like to once again thank all who helped me out with my questions on the fuel draining and the carb issues. I'm sure I'll have more(as I am the world's worst mechanic :-)This forum is the best!
L Karpman

Larry, I hope you took advantage of the empty tank to allow you to remove, and clean, the screen filter at the outlet. Bud
Bud Krueger

Bud, I wish I could. Long before I bought this TD a PO obviously had a leak at the tank outlet and couldn't stop it or didn't try. There is what "was" a putty like "blob" around the outlet that has of course hardened but keeps the leak at bay. As It has not leaked in the 8 or so years I have had the TD, I chose not to bother with it. It is way down on my to do list, as the last thing I need is a tank that will not seal.
L Karpman

RC,
You can buy a 3/8" BSP brass plug and washer in the DIY and tap it to fit a shut off valve. Holden UK sell fuel valves.
http://www.holden.co.uk/displayproducts.asp?sg=2&pgCode=017&sgName=Hardware&pgName=Fuel+Systems&agCode=0122&agName=Fuel+Taps
Vintage supplies sell all sorts of drain taps and other interesting bits and pieces:
http://www.vintagecarparts.co.uk/categories/vintage-car-parts-taps-pipe-and-fittings-taps-drain
The valve I used was from a tractor. Thread was unknown as I bought it off ebay. I removed the thread in the lathe and soldered it to a standard 3/8" brass plug drilled to match. If using a brass tap for petrol I would recommend a thin smear of fuel proof (eg Reinzoplast) sealant. You have to break the seal to drain the tank. That is where fuel valves have the advantage but the brass valve does look period.
Regards
Declan
D Burns

Look at the "Anglo parts" Website and click on "view parts Illustration".
https://www.angloparts.com/en/catalogues/group/776

Their drawings are excellent and you can download their catalogue free of charge-also excellent as they give thread sizes which most supliers don't.
Pricewise you would need to take out a second mortgage on you house!
Regards
Declan
D Burns

I think Larry and Declan have alluded to it but whilst you are underneath the back you may as well install an in line fuel cut off valve.

I have mine installed between the tank and my backup facet pump. I can reach down and under the car and easily and quickly switch the petrol off.

If you ever have an issue with the car its reassuring to be able to quickly disconnect the fuel at the back of the car from the heat and electrics at the front.

Its also a tiny nod towards making the car a little harder to steal.

I am trying to train myself to disconnect the battery and switch the fuel off when I am working on the car or not using it for a month or so.

By the way. Before you ask. The answer is yes. I have spent an hour wondering why the car wont start only to realise I had switched the fuel off a week or so ago.





Doctor Bob

Can anybody who fitted a drain tap on their gas tank tell me where they got it and what fittings did it need? I'd like to do the same...
Geoffrey M Baker

Interesting that this subject is on a thread today as I did it this afternoon. My approach to removing gas from the tank is to have the car elevated on jack stands, use clear tubing with a fuel filter in line with the tubing, attach the tank end of the hose to a stick so it stays at the bottom of the tank and siphon the gas into a five gallon gas can. How long it takes depends on the diameter of the hose. And because I used a filter I will use this gas in my every day car however I will run it thru a second filter.
F. Driver

One drain tap is available from Paul Beck Vintage Supplies at: http://www.vintagecarparts.co.uk/en/ P/N is 203 - straight drain tap 3/8 BSP threads, price is £13.20 plus shipping. Cheers - Dave
D W DuBois

Try vintage supplies. They have a great selection.
You need a 3/8" BSP thread.
http://www.vintagecarparts.co.uk/search?query=Tap
No 574 would fit.
Regards
Declan
D Burns

Dave,
I think our replies crossed!
Declan
D Burns

I think part #574 would be better, it is intended for fuel whereas #203 is a radiator drain. You can't cap it so if the lever got knocked it would just drain out... I think #574 with a 3/8 cap should do the trick.
Geoffrey M Baker

http://www.ebay.com/itm/3-8-Inch-BSP-Brass-Cap-British-Standard-Pipe-Thread-Fitting-/121482456297?pt=UK_DIY_Materials_Plumbing_MJ&hash=item1c48eb2ce9

is a cheap cap that will fit.
Geoffrey M Baker

drain valves available from Spruce Aircraft. install by drilling hole in drain plug, thread hole, install drain valve. replace drain plug.
R W Hinton

RW: That brings up and interesting concept. Most aircraft sit outside and a problem is that condensation collects inside the fuel tanks. Luckily water is heavier than gasoline and it sinks to the bottom. Every pilot is required to drain off a bit of fuel from each tank before they take off to insure no water is brought into the engine which could cause it to stall (and the aircraft too from that point). Usually a clear cup is used so they can also inspect that the fuel is the correct octane too. They are colored.

It might not be a bad idea to install aircraft fuel drains in the cars too since most of them sit for long periods of time without use. It also gets rid of the junk that collects at the bottom too.

Your idea is a good solution for for sediment and water clearing as well as just draining the tank.
Christopher Couper

What is the advantage of an aircraft fuel drain vs any other kind of a drain tap?
Geoffrey M Baker

The first advantage that comes to mind is because they're intended to be use frequently for the reasons stated by Chris. Jud
J K Chapin

Not to belabor the point, but I googled "aircraft drain" and found a bunch of them. Some appeared to have a hole drilled through the handle so that they could be wired into place and avoid accidental opening during flight. Fine...
But why not just a regular drain with a cap to seal it? That way it can't open accidentally. And you don't have to mess with drilling and tapping to fit a US thread.
Unless someone knows of other, better reasons to use an aircraft fuel drain, I think I'm as well off using a 3/8 BSP fuel valve, with a cap to keep it from accidental opening. Less work, same cost, same advantages.
Geoffrey M Baker

Here's my drain valve on the tank. It's a standard 3/8 BSP valve, nice and small, and I mounted a simple locking mechanism to keep it from turning. I'll be adding a 3/8 cap as a redundant safety measure. The valve I found on ebay for $3.48 and free shipping.


Geoffrey M Baker

Apply caution purchasing cheap valves, "you only get what you pay for". Years in the pneumatic and petro-chemical industries have proven "Swagelok" to sell reputable products for a variety of applications.

Graeme
G Evans

I have a spare radiator drain cock in stainless steel somewhere (supposedly originally fitted to a YT) & wondered whether this would work in lieu of the drain plug? The tank is 3/8" BSP but I'm unsure of the radiator drain cock thread & size which I think is probably also BSP but a little smaller? If so I would then need a BSP adaptor 3/8" male to ?? female? Are there any likely clearance issues? Otherwise I could just tap the appropriate radiator thread into the drain plug. Also is polytetraflourethelene (PTFE) thread sealant tape OK to use with fuel in this instance? (as I'd read somewhere that it was not recommended). Cheers
Peter TD 5801
P Hehir

People here have said ptfe tape isn't good in fuel lines so I don't use it. There is is clearance I think for any small valve.
Geoffrey M Baker

No worries using PTFE tape with petroleum providing you use the correct one. I use a pink coloured tape which is correct for the application. There are at least 5 different varieties of PTFE tape available ensure you purchase the correct one for the medium you wish to seal.

When you use any PTFE tape never apply it to the first thread roll this negates tape ending up blocking the fitting annulus.


If you dont want to take this tack purchase a product sold under the name of "Stag", been around for decades.

Graeme
G Evans

Ptfe tape is for home and commercial plumbing jobs. There are plenty of high quality automotive and aviation thread sealants on the market. Permatex in the U.S. Is just one manufacturer. Regards, Tom
tm peterson

Anybody able to ID the thread on the radiator drain cock? I'd like to pick up the brass fittings today (or tap the plug if I can't find an adaptor) & then fit the stainless cock to the fuel tank. While I'm there I'll also get a couple of plastic 3/8" BSP plugs to use when sealing the tank, which I'll remove before the KBS Gold seal goes off. Cheers
Peter TD 5801
P Hehir

Incorrect information is being imparted regarding PTFE tape, this is one manufacturers application guide;

http://www.laco.com/assets/1/31/thread_chart.pdf

Note the versatility of their pipe thread tape product.

Graeme
G Evans

Thanks Graeme for the Slictite info. Because of its multiple uses (concentrated acids, gas, fuel, diesel etc), that will now be my PTFE of choice. The radiator drain cock thread is 1/4" BSPP (info from Dave & Lew). The 3/8" BSPP male to 1/4" BSPP female adaptor (bush) is about $4 in brass, a new 3/8" BSPP plug in brass (for use during the sealing of the tank as plastic plugs were unobtainium), is also $4 & a 1/4" BSPP tap about $20. I can either use the 1/4" tap to thread the existing plug & then screw in the cock with the all purpose PTFE or just fit the bush & cock using the PTFE, if there are no clearance issues. Cheers
Peter TD 5801
P Hehir

Peter

You are entering into a whole different field of play once you use parallel BSP threads. Normal practice is to use a fibre washer to seal the female and male fitting faces. High quality male fittings have an "O ring" groove machined in the male fitting face.

I know you are not dealing with high pressure here however I would not contemplate going to a domestic plumbing fitting wholesaler for the components you require there are better quality fittings available from other sources.

Graeme
G Evans

I'll take your advice Graeme. Can you recommend a Sydney supplier of the 3/8" male BSPP to 1/4" female BSPP bush? Cheers
Peter TD 5801
P Hehir

Peter

A couple of contacts:

Swagelok

1/72-74 Woodfield Boulevard, Caringbah NSW 2229
(02) 9526 6155

Tubefit

National Customer Service
Phone: 1800 777 299

Swagelok will even send a rep out and make design recommendations for any industrial plumbing application. Pricing is high, however you only get what you pay for.

Graeme
G Evans

Thanks for the heads up Graeme. Tubefit are unable to supply a BSPP item as only the female side of the bush has the parallel thread. Swagelok are not sure if they can help & WRMB. Reece when pressed said their fittings "do have a slight taper"... Hmmm.. Not as easy as first thought. May have to revert to plan B & buy a 1/4" BSPP tap & cut a thread into the existing plug. Cheers
Peter TD 5801
P Hehir

Peter

More options, who are listing BSPP Reducing Bushes

Ryco

78 Hassall Street,
Wetherill Park, NSW 2164
Tel: +61 2 9765 2500

Pirtek

Phone:
134 222
(02) 8822 9000

Product is even on Fleabay in the UK.

Graeme
G Evans

Nice product, just don't use it on your cars. Leave it for home and commercial plumbing. Regards, tom
tm peterson

OK Graeme, you can say "I told you so".
I got around to fitting everything back together and added gas to the tank... and it leaked from the valve. I drained it, removed the valve and put the plug back in... dry as a bone.
Live and learn.
Geoffrey M Baker

Why the leak Geoff? Faulty valve? Incorrect thread? Poor sealant? I'm still keen to fit the valve so am curious as to what failed exactly. Cheers
Peter TD 5801
P Hehir

Peter, it was just a crappy valve. I was going to smear on some sealant but when I took it off again it unthreaded at the wrong stage, (there was a joint right at the ball itself) making it much harder to get off and when I looked at it I could see just how poorly it was made... so I nixed that. When I take the tank off again in the spring to repaint it, I'll put a good quality valve on.
Interestingly, I put no sealant on anywhere and nothing leaked at all - if it works, don't fix it - so I'm not going to use sealant except possibly when I fit a new valve on.
Geoffrey M Baker

The reducing Bush (024.0604 Bush Parallel) came from Fittings Express in Brisbane for just $2.30. It was specially made ensuring both the 3/8" BSPP male & the 1/4" BSPP female threads were both parallel. Pic attached. (The courier cost to Sydney was $16, 7 times the cost of the bush!). Cheers
Peter TD 5801



P Hehir

This thread was discussed between 11/09/2014 and 29/01/2015

MG TD TF 1500 index

This thread is from the archive. The Live MG TD TF 1500 BBS is active now.