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Tap pump for drain plug. Tap question

Discussion in 'Truck & Equipment Repair' started by shep28, Nov 10, 2012.

  1. shep28

    shep28 Member
    Messages: 84

    The hex head on the drain plug was ruined and I ended up having to drill it out in frustration. Do I have to use a plumbers tap to make new threads, so it does not leak? or can I use a harbor freight tap?
  2. clark lawn

    clark lawn PlowSite.com Addict
    from NE ohio
    Messages: 1,233

    Chances are that its pipe thread. Did you mess the threads up? You may have to use a helicoil or a keensert. I don't know that you will be able to tap a pump housing successfully.
  3. shep28

    shep28 Member
    Messages: 84

    Threads need to be retapped. Was 3/8 before the mishap :eek:
  4. clark lawn

    clark lawn PlowSite.com Addict
    from NE ohio
    Messages: 1,233

    Forget the helicoil I wasn't thinking properly it will leak. Go to someplace that sells hydraulic fittings they should have the correct tap.
  5. 2COR517

    2COR517 PlowSite Fanatic
    Messages: 7,115

    3/8 pipe thread is 3/8 pipe thread
  6. CR128VT

    CR128VT Junior Member
    from Vermont
    Messages: 25

    The tap needs to say npt....for example 3/8npt
  7. jasonv

    jasonv PlowSite.com Addict
    from kannada
    Messages: 1,114

    The drain bolt is PROBABLY NOT pipe thread, and certainly doesn't need to be. The pump base should be aluminum, easy to tap. Once the new hole is drilled and tapped, v-notch the start of the hole. You can gently use a larger drill bit to do this. Try to get a new bolt with a comparitively large head if possible. Put an O-RING on the bolt. When you tighten the bolt down, the o-ring will sink into the v-notch and seal against the bolt head.

    An alternative to the v-notch and o-ring seal method is to use a copper [crush] washer like the oil drain bolt on your engine.

    I suggest a STAINLESS STEEL bolt as the new plug, and don't over tighten it.