Size of Fuel tank drain plug

hornet53
hornet53 Senior Contributor
edited November -1 in HUDSON
I let the gas sit in my Hornet for too long! Once the car starts, it just smells like it's burning varnished fuel. I really should send the tank out for boiling and coating this winter also. Either way, step 1 is draining the tank.

BUT, I thought the drain plug size was 3/8in and I could use my ratchet to remove the plug and I was WRONG.

What size is the square drive needed to undo the drain plug? I'm going to go out tomorrow and buy one, but I don't need a whole set to only use the one size.

Comments

  • hudsonguy
    hudsonguy Senior Contributor
    edited November 2010
    Since you're already planning on taking out the tank, I'd suggest avoiding trying to remove that plug unless you have knowledge that it might not be that difficult to remove. In other words, unless it's been out fairly recently, and was reassembled with anti-seize compound on the threads, it might not come out too easily. I've seen the brazed connection fail when these are really frozen in there, and then you've got a mess.

    At least the last time I did what you are doing, I just siphoned all I could get out, which was all but a gallon or two, and then just removed the tank from there. Once the tank is out and clean and dry a little torch heat will help get the plug out, if it's really frozen. Good Luck
  • hornet53
    hornet53 Senior Contributor
    hudsonguy wrote:
    Since you're already planning on taking out the tank, I'd suggest avoiding trying to remove that plug unless you have knowledge that it might not be that difficult to remove. In other words, unless it's been out fairly recently, and was reassembled with anti-seize compound on the threads, it might not come out too easily. I've seen the brazed connection fail when these are really frozen in there, and then you've got a mess.

    At least the last time I did what you are doing, I just siphoned all I could get out, which was all but a gallon or two, and then just removed the tank from there. Once the tank is out and clean and dry a little torch heat will help get the plug out, if it's really frozen. Good Luck

    I had it out a few years ago, but I was working out of my dad's toolbox at the time so I don't remember the size of the hole.
    I just don't know if it's frozen or not. I'd like to at least try to get it out as it is pretty handy having it there.
    Also, the fuel seems to be seeping out from the drain plug, so it needs to come out and get cleaned and maybe replaced anyway.
  • Uncle Josh
    Uncle Josh Senior Contributor
    Might be able to find a square head bolt that'll fit and use a stud or pipe wrench on the screw part.
  • Ol racer
    Ol racer Senior Contributor
    FYI
    I suggest measuring across the plug. My '53 is away for the winter so cant measure tonite. I think if you tried a 3/8 ratchet and was too small its a 1/2" plug. To save buying a 1/2 flex bar, just buy a 3/8 to 1/2 'adapter' at Sears or Auto Store. It slips over a 3/8 making it 1/2".
  • [Deleted User]
    [Deleted User]
    It Seem's to me I found it was in between 1/4 and 3/8. If I recall correctly I found a piece of tool stock in my lathe drawer that fit. I wouuld guess it was 5/16 square stock.
    Roger
  • RL Chilton
    RL Chilton Administrator, Member
    Tallent R wrote:
    It Seem's to me I found it was in between 1/4 and 3/8. If I recall correctly I found a piece of tool stock in my lathe drawer that fit. I wouuld guess it was 5/16 square stock.

    Roger

    That's right. I took a short 3/8" drive extension (2") and ground it down to fit. Now it's solely my fuel tank drain plug tool.
  • MikeWA
    MikeWA Senior Contributor
    Another possibility is to find a piece of key stock that's the right size, and twist it with the appropriate wrench.

    Having BTDT, I would just "try" the plug very gingerly while the tank is in place- tank sheet metal is pretty flimsy. Besides the obvious damage to the tank if you rip out the fixture, there's also the large amount of spilled fuel that you'll have no way to stop, once it starts coming (have several buckets available, at least).
  • Clutchguy
    Clutchguy Senior Contributor
    The correct size is 11/32th's. It is a pipe plug socket. I have 4 of these in different sizes. It is hardened,and also has a slight tapper to the end. Snap-on Tools sells it. I think the number is PPM-412a ??. Find there catolog online for the correct # I have found these to be priceless. Something to ponder is that when taking this plug out,NEVER use a drop light with an incodesent bulb and have at your finger tips,enough drain pans to allow for 20 gallons of fuel. This tool works very effiecient and if the plug won't come out,will allow you to twist it right out of the tank.. Good luck,CG
  • GrimGreaser
    GrimGreaser Senior Contributor
    Yeah, I was dealing with this problem last weekend. I filed a cheap old extension I had down to fit, and promptly twisted it like a barber pole (did I mention it was cheap?). Not wanting to file on my good extensions, and unsure exactly how much gas was in there, and seeing that someone had previously repaired around the drain I felt attempting to wrench on that was a bad idea. So I just got the floorjack out and dropped it as-is. Got 7 gallons of 30 year old gas out of it. Glad I didn't bust that fitting.
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