Broken screw on overflow pipe

Discussion in 'Shower & Bathtub Forum & Blog' started by DanGles11, Nov 11, 2011.

  1. DanGles11

    DanGles11 New Member

    Messages:
    6
    Location:
    Minnesota
    I was removing the two screws that holds on a chrome overflow pipe cover for a bathtub and one of the screws has broken off. It is still attached to the screw hole in the PVC pipe. All that is left of the corroded metal screw is a small sharp point that won't come out. It is probably only about 1/8-1/4 inch long and it is pretty much impossible to grab onto it with anything. There is no access to it from the back side. Should I try to grind it down flat with a dremel type grinding bit and then try to remove it with a screw extractor? Also, the gasket looks somewhat dry and cracked (20 years old). Will that be easy to replace keeping in mind the only access will be from the overflow opening on the tub.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,334
    Location:
    New England
    An easyout may be the best choice. You can normally fold or distort a new gasket through the hole from the front. Just don't drop it!
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,272
    Location:
    Cave Creek, Arizona
    The plastic is a LOT softer than the metal, so if you do NOT drill or use and extractor PERFECTLY, you WILL damage the overflow fitting. The screw must have been seriously deteriorated to break off, since the plastic should NOT have held it tightly. I cannot tell you how I would remove the screw, because I do not know without seeing the actual situation, although I might get an overflow plate with a single center hole and use a long screw, or bolt, to fasten it through the back of the overflow fitting.
    Last edited: Nov 12, 2011
  4. philbrunet

    philbrunet New Member

    Messages:
    3
    Location:
    Somewhere in Quebec
    Hi,

    I have a similar situation.
    The two screws bolted inside the PVC tubing are stock because their heads fell off by themselves after years rusting.
    This is a case of prolongated rusting. Also, the sheared surface is conic, making drilling very difficult. Some filing might be required to flatten the surfaces.

    I am worried that using a screw extractor drill bit to drill the initial holes in which to insert the screw extractor will strip the thread inside the PVC. That is because there is no way the bolt is stock hard enough in the plastic thread to resist the rotation force applied by the drill. If anything, the bolt will start rotating during drilling and strip the PVC thread, then it is game over. We are not talking a bolt stock in a metal part.

    I do not understand what could be the solution using an adaptor, therefore bypassing these two holes and fixing the cover in an other way. There is no undercut inside the PVC tubing to allow that.

    Then drilling in the back of the PVC tubing with a long screw might cause water infiltration unless you put some silicon on the tip of the screw to seal it.

    Attached Files:

  5. Hackney plumbing

    Hackney plumbing Homeowner

    Messages:
    1,174
    Location:
    Alabama
    If you have access from the back I would cut that out and replace it. Dont bother trying to get the screws out.
  6. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,272
    Location:
    Cave Creek, Arizona
    quote; Then drilling in the back of the PVC tubing with a long screw might cause water infiltration unless you put some silicon on the tip of the screw to seal it.

    1. It would be water exfiltration.
    2. It would be almost impossible for water to reach the screw hole in the rear of the fitting, because the plate would limit the flow in and the water would have to back up in the overflow fitting, (and also the tub", to reach that level.
    3. Kohler has some drains for special tubs that come with the hole tapped in the back of the overflow, so it is NOT some handyman idea.
    4. you might drill a very small hole in the center of the bolts, then use one of the "extractor drill bits", that rotate in reverse to try to remove them.
  7. philbrunet

    philbrunet New Member

    Messages:
    3
    Location:
    Somewhere in Quebec
    First of all, thanks for your input Hackney plumbing and hj.

    1. ok for the terminology
    2. point taken
    3. good to know this method is used
    4. the problem is the pipe is not fixed properly inside the wall and moves in when push while drilling. I wouls have to restrict it when my finger then drilling just beside. What about stripping the thread while drille the hole, because of the force applied to the PVC?

    Tks.
  8. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,272
    Location:
    Cave Creek, Arizona
    You might be able to use a small "C" clamp to stabilize the pipe while working on it. That would also hold it good enough so an extracting bit might grab the screw.
  9. philbrunet

    philbrunet New Member

    Messages:
    3
    Location:
    Somewhere in Quebec
    The results...
    Since this is an apartment, the landlord came to fix it himself. He is an retired plumber and I did not want to risk damaging the PVC piping.

    1) He tried drilling into the screw strategy.
    The screws were harder than any tool bits.
    Clamping the loose PVC tube to the tub using the vice grip did not really help drilling.
    The drill bit just kept being swept aside.

    2) Solution
    He left alone the two screws, then using longer screws with a conic end, he drilling on an angle to go grap into the PVC walls around the stocked screw. I think the screws self tapped. That did it for a patch job until a new tub is install one day.
    This solution prevented any holes through the PVC pipe.
  10. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    27,272
    Location:
    Cave Creek, Arizona
    IT would not have been my solution, but as long as both of you are happy with it, that is all that matters.
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