Optimus 99 stuck filler cap

Discussion in 'Fettling Forum' started by nickinak, Mar 17, 2019.

  1. nickinak

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    I am starting to clean up my stoves and will likely have to replace all the tank cap seals due to age and Fairbanks seems to be a harsh climate for seals. On my 99 the cap will unscrew about 1/8 to 1/4 turn then stop. Other that soaking in penetrating oil is there a method to use? The stove was purchased new around 1980 and has sat unused until now. Thanks
     
  2. JP2

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    Hi
    Is it the original cap? If yes, I will put a leather to protect around the cap and I will go back and forth with a plier.
    Good luck
     
  3. Lennart F Sweden

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    It could be a sticky seal or corrosion in the threads - try some penetrating oil with instant corrosion-off like WD40 or similar - a few drops in outer position, turn the cap in and give more oil on the thread, repeat gently turning and oiling until it doesn't soak in more, stop between inner and outer position. Then wait for ½-2 hours before oiling and turning the cap again - if it doesn't move more now you should try to heat it somewhere about boiling temp and turn again.
    Be aware that excessive force can destroy the threads.
     
  4. OMC

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    nick
    I enjoy your Fairbanks input and view.

    I like using heating vs cooling of brass but not suggesting that here.

    I vaguely recall similar issue (seal stuck to fill tube?), I do not have your answer. Worse yet I've got a *question :shock: .

    Before going to heat vs cool, you can start w/heat.
    Question, how hot can we set the oven w/o concern of solder joints being effected?
    I had zero concern when I began doing this but I think I recall a member placed a 3 legger in the oven only to hear the legs fall of.
    You have to have gloves to manipulate hot stove and tools.

    thx omc
     
  5. JP2

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    I am wondering if it is not a better idea to go by the wick side now then you will be able to empty the tank a rinse it. After that it will be safer to use heat on the cap side.
     
  6. Lennart F Sweden

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    A stove unused for 40 years would probably not have the tank filled with volatile contents, heating it with steam or boiling water would not be a big hazard.
    Regular soldering tin use to have a melting point well above 200 Centigrades and closer to 250 - somewhere 400-500F.
     
  7. Trojandog

    Trojandog United Kingdom Subscriber

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    I'm wondering if the washer has shrunk, gone rock hard and stuck to the tank spiggot. The 1/8 inch play might be the slack until it catches on the filler cap thread. You don't need massive heat to soften a hard washer, boiling water will do. I'd bung the tank in a pan, boil it for a few minutes, then try unscrewing the cap using a protective leather wrap. You could also try removing the burner pipe, spaying in a s**t load of WD40 and standing the tank on the filler cap for a couple of hours - attack the problem from the opposite direction.

    Terry
     
  8. nickinak

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    Thanks to all who replied I combined methods soaking with WD40 then used @Trojandog suggestion of boiling water heating came off with just hand pressure.
     
  9. JP2

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    Nice, good job
     
  10. snwcmpr

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    Just an FYI, WD40 is not considered a penetrating oil. It is a water displacement solution.
    Kano Kroil is great, or make some with 50/50 acetone and ATF, automatic transmission fluid.
     
  11. Majicwrench

    Majicwrench Subscriber

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    WD 40, right on back of can "penetrates to free stuck corroded parts"
    It works well as a penetrating oil, I have used it for decades, though there may be better choices.
     
  12. Doc Mark

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    Morning, All,

    Congrats to the OP for getting his cap off, and well done, @Trojandog , for your great suggestion to him! I used to use WD-40 for many years, as “back then” it was touted as a good rust preventative, as well as a penetrating oil. It was horrid for rust protection, overall, but did work a little as a penetrating oil. However as @Majicwrench noted, there are better choices, today. I like the 50/50 mix, myself, and have just used it for several onerous jobs, on which it worked great. Much better than WD-40. In any case, getting back to the Opti 99, it’s a wonderful little stove, though I’m not a huge fan of cooking in the lid/pot. Heating soup, or tea, is OK, but for actual cooking, I must prefer to use a regular pot with it’s own lid, and thence use the 99 top as an additional windscreen. Just my ‘tuppence, and many others like using the top, as a pot. Congrats on fettling yours back to full use condition. Have fun, and God Bless!

    Every Good Wish,
    Doc