Bolt stuck removing Heater Core

Discussion in 'Interior Restoration' started by smallblock80, Sep 9, 2019.

  1. smallblock80

    smallblock80 New Member

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    Jul 1, 2014
    Little Rock, Ar
    I've been working on removing the dash out of my 80 z28, and am working on the heater core. I've removed the two bolts on the inside & the top of the heater box is loose. I've removed the passenger inner wheel fender & I see the stud with the nut attached under the lower heater hose. However, I cannot get the nut off. Everytime I try to turn it with a wrench or impact, the stud turns with the nut, possibly due to being rusted, I'm not sure. I've tried holding the stud so it doesn't turn with vice grips while i turn the nut with a wrench but I cannot get the stud to stop turning with the nut. I've attached some pictures of the two bolts I've removed on the inside, as well as the stud/nut that keep turning below the lower heater hose.

    Any help or advice would be appreciated.

    Attached Files:

  2. RS1979

    RS1979 Veteran Member Lifetime Gold Member

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    Jun 18, 2013
    Memphis, TN
    Spray PB Blaster on the threads. Be sure to get some inside the nut. Give it some time to soak in. It should come out.
  3. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    Feb 26, 2004
    Bloomington, MN
    Is this an A/C equipped car?
    If so... The lower stud by the heater hoses can be removed by drilling out the head of the stud from the interior of the car.
    It can be replaced with a 1/4" bolt.

    There's another stud near the rear of the valve cover which is hidden by a part of the evaporator box.
    (That's the one which gave me trouble the last time I did this job.)
  4. Scott51

    Scott51 Veteran Member

    Likes Received:
    Jan 2, 2012
    New Zealand
    Clean up the exposed threads with a wire wheel and soak everything with PBlaster, WD40 CRC etc

    Thread two more nuts on the end of the stud and lock them together by tightening the outer one with a socket while holding the inner with a ring spanner.

    Move the ring spanner onto the stuck nut and try to undo it using the socket on the outer nut to stop the stud from spinning.

    If that doesn't work for some reason weld the outer nut on and just grind or cut it off once the stubborn nut has broken loose or get a cheap nut splitter and split the stuck nut.

    Either way you still have a useable stud and heater box afterwards

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