cross threaded drain plug 530Exc

Discussion in 'The Garage' started by Vicks, Feb 14, 2014.

  1. Vicks

    Vicks gets stuck in sand

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    I bought a used '10 KTM 530Exc and looks like the so called mechanics who the PO used, cross threaded the engine oil drain plug damaging the drain hole as well as the plug threads.

    There is very little space between the drain plugs and the cross member on the newer 530 Exc motors and it looks like they started the drain plug crossed but somehow thankfully, the remaining threads look like they're undamaged. The engine oil drain hole threads are more damaged than the gear oil drain hole.

    engine oil drain hole threads... you can see the first 3-4 threads crossed up here
    [​IMG]


    [​IMG]


    the gear oil drain hole threads. only the 1st thread seems to be damaged in this one
    [​IMG]


    [​IMG]



    They managed to even screw up the engine oil drain plug where the threads have got crossed and stretched.
    [​IMG]


    [​IMG]



    I first thought i'd simply run a tap gently but i'm afraid that :
    1. the tap too will start out wrongly because of the crossed first few threads, and then it'll surely damage the remaining good threads.
    2. there is not much space behind the cross member to fit a 17mm tap without misalinging it with the drain hole.

    Another option would be to drill out the damaged few initial threads so that i'll have good threads to start the plug. But my concern is :
    1. There is not enough space to hold an electric drill, with a long drill bit (17mm drill bit is going to be quite long)
    2. as the cross member is directly behind the drain hole, i may not be able to line up the drill bit correctly and end up with misalignment issues.


    following pictures show the space between case and the cross member at drain hole. The distance is approx 60mm or 2.5"
    [​IMG]


    what you guys reckon i could do ? do i need to get the engine out (PITA) to repair the threads ?
    #1
  2. ohgood

    ohgood Long timer

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    get a round file and go to town on those female threads. or have a machinist buddy do it. its not a big deal. you're just looking to chamfer out the damaged area.

    and replace the plugs that go in them, they're shot.
    #2
  3. Vicks

    Vicks gets stuck in sand

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    Thanks for the suggestion but i didn't quite get it when you say chamfer out the damaged threads using a round file.

    Do you mean to say that the round file has to be used axially (which doesn't make sense to me) or radially on only the few initial threads to file them down ?

    Yup, getting new plugs from the dealer tomorrow. I'm not even thinking of repairing it (the plug ie.,).
    #3
  4. Switchblade315

    Switchblade315 Long timer

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    if it where mine. get new plugs and be very careful each time you put them back in. to fix it right you'll need the motor out so you can make sure everything is strait. if anything take a curved pick and try to see if you can remove any loose threads from the damaged area. I would not try to fix that in the frame.
    #4
  5. ohgood

    ohgood Long timer

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    stick the tip of a rat tail file in the hole and carefully use a sawing motion in and out. all you want to do is remove the damaged threads, then polish in a circular motion with some sand paper. if it looks uniform afterwords, you're done.

    if the section of the engine was removable that those holes are in, I would remove it and run a tap from the inside out, it would clean out the threads just fine.

    the important part is when reinstalling the plus, that you turn them backwards, and "crown" the threads, then gently start turning the right direction to install the plug. you'll see what I mean when you try it.
    #5
  6. tkent02

    tkent02 Long timer

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    I would just use new plugs, get under there and look to make sure they start straight, every time. If they won't start straight, pull the engine and fix the hole.

    I wouldn't try to tap the hole with the engine in place, too hard to get it straight.
    #6
  7. Vicks

    Vicks gets stuck in sand

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    I'll give new plugs/bolts a try once. If i'm gonna have to down the engine, i might as well give the other options a try first.



    that makes it clear now. I know what you mean about crowning the threads. Thats how i always start a bolt/screw to ensure they are not cross threaded. Looks like who ever worked on the bike previously missed that class.

    The cross member is not removable, the only way to avoid it would be to down the engine from frame. so no chance of running a tap from the inside....

    Yep, tap seems to be out of the question.


    Another problem i can see is that once i clean up the first few threads, the plug will have only 2-3 threads remaining in the sump to tighten against. That wouldn't be good for a large bolt of this size me thinks. I'm thinking of sourcing a longer bolt to solve this problem but it has its own complications (oil screen fit into these plugs/bolts with o-ring, so there are grooves on the inside of the plugs - this will need to be replicated on the longer bolt which i find). Lets see what i can source tomorrow. Longer bolt + cleaned up threads look like the best solution for now, without taking the engine off the frame.
    #7
  8. BOBaloo22

    BOBaloo22 RIP Baby Girl

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    I had a similar problem, I did tap it in place. I dipped the tap in grease to catch the filings and had my bro in law eyeball the tap from top to bottom while I eyed side to side. It worked great for me. I ran a few Qts of cheap oil through the motor fill. I filled with oil ran for 5 mins or so and changed again. Its been fine for over 20K. Hope this helps, and yes it was very scary but it was a HD and I had no choice.

    Bob
    #8
  9. sailah

    sailah Lampin' it

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    If that were mine...

    I'd pull the motor, stand it so the plugs were facing down. Tap it for a timesert using grease on the tap. Insert timesert, replace motor. Flush with a quart of oil, then run a change oil for five minutes. Refill, check screens and ride. And replace all plugs obviously. Not easy, but fixed right.
    #9
  10. boasjohn

    boasjohn Adventurer

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    What size thread? i have a 12mm sparkplug back tap pu in hole at the good threads and screw out to clean up the bad threads. dont know if the make them in outer sizes also 6" long if space is a issue
    #10
  11. GreaseMonkey

    GreaseMonkey Preshrunk & Cottony

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    First off, if you want to clean up the threads the proper tool to use is a "thread chaser" and not a tap.

    If you think about it, you want to leave as much metal there to support the threads on the plug, and a tap works by removing metal.

    As Boasjohn mentions, often these are 12mm or 14mm and 1.25 pitch which is identical to spark plug thread sizes. Here is an example of a chaser:

    http://www.sears.com/craftsman-spark-plug-hole-thread-chaser/p-00947321000P

    Simplest way to tell is just see if an old spark plug will thread into the hole.

    However, if that bike were mine I would simply clean the threads up well and install a "piggyback oil drain plug" that looks like this:

    [​IMG]

    Here is the link so you can look at it and read the description:

    http://www.pepboys.com/product/details/8328904/00826/

    Get that started, and then install it with a suitable adhesive/sealant such as JB Weld or Locktite and then you do not have to worry about it ever again.

    I see you are in Abu Dhabi but I am sure you can source one locally, or have a friend with an APO to get one shipped to.

    Lastly, if you ever have to tap an oil pan you do not have to go to extremes to get the chips out of it, it does not make that many and to be honest, they'd just sit on the bottom of the pan if you left them in but in reality just do your tapping and then use a rag or paper towel wrapped around a pencil or a finger to clean the chips out, takes less than a minute to do.
    #11
  12. Vicks

    Vicks gets stuck in sand

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    The drain hole on the left is an M17 and the one on the right is M16.

    A back tap such as this would be ideal and make my life so much easier but i'm unable to find ones in 17 and 16mm sizes.



    Thanks, i wasn't aware of the thread chaser.

    Can't install a piggy back drain plug or any kind of adapter as this plug is not just a drain hole plug, but also carries the oil screen (see pictures in my original post) which sits in a groove on the inside of the plug.

    Drilling and tapping etc with the engine mounted is a no-go as you can see from my pics above.
    #12
  13. Vicks

    Vicks gets stuck in sand

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    and then i found this

    link
    #13
  14. H96669

    H96669 A proud pragmatist.

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    They sure reefed on that oil plug from the marks on the head.:eek1

    Get the right files and fix the easier ones first. That would give you some practice for the oil plug.

    And after filing, get some bolts of the right size and make your own thread chasers.

    If you are worried about the filings, set up some suction next to the area as you work. My ShopVac does fine for that.

    That's only some of the files I have in the house, the ones I may have heated up and bent for better reach in threads are in the shop.

    [​IMG]
    #14
  15. ohgood

    ohgood Long timer

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    this is exactly why I recommended filing the damage vs a newbie to grab a tap and start making a bigger problem.

    so often folks mean well, but end up choosing the wrong method
    #15
  16. 2WheelsOnly

    2WheelsOnly woodsrider

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    Since it has an oring on the bolt, you should not need to torque it hard to seal. If you are concerned about it vibrating loose, you could cross-drill a small hole through each bolt head to safety wire between the two bolt heads. They won't rotate that way. Just some alternative ideas.
    #16
  17. Vicks

    Vicks gets stuck in sand

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    So i thought long and hard at the available options. I wanted to do a reasonably good repair without any goof ups so that the cross threaded hole didn't get any worse.

    I had a few choices, amongst using a thread chaser - either buy one (but none were available in M16 & M17 sizes) or get one fabbed up (time - efforts) Or buy one of the other thread cleaning tools i had linked earlier for (delay in getting it from US - couldn't find one locally). In the end i chose to go with filing off the first few threads and a longer drain plug in order to give it enough threads to securely go into the hole.

    First i went to a local lathe shop and got new plugs turned.
    [​IMG]

    the M17 is a non-standard size and the guys had to turn up a new one from a larger bolt. They also had to drill out the internal aand cut a groove to hold the screen as well for both the longer plugs.
    [​IMG]


    then i bought a set of these nice little files (i only had the regular 9" long round file with me) and got to work slowly, taking my time to smooth out the first 2-3 threads which were damaged.
    [​IMG]

    After every few movements, i would using lube oil, clean up the filings from the hole. Finally, success when the new bolts went in true without much issues.
    [​IMG]

    made sure that both the plugs went in all the way properly, fitted the screen on the engine oil plug and now have to wait until monday to get a new screen for the gear oil plug as the shop guys lost it while turning up the new plugs:huh

    Thankfully i didn't have to down the engine or make the problem worse. Thanks to all who gave me your suggestions and advise, it was very helpful in taking the right decision and more over, doing the job right without goofing up.
    #17
  18. ohgood

    ohgood Long timer

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    you got it fixed and got to smell cutting oil in a machine shop for a while too, sweet!
    #18