harmonic balancer nut 2.5L engine

mactavish2mactavish2 Member Posts: 3
edited September 2014 in Subaru
Can't get harmonic balancer nut to come off. Is it a reverse thread?


  • mactavish2mactavish2 Member Posts: 3
    I cannot get the harmonic balancer nut off. Tried heating it. Is this a reverse thread from most engines?
  • xwesxxwesx Fairbanks, AlaskaMember Posts: 15,848
    Are you referring to the 22mm bolt on the front of the crankshaft? I believe that one is reverse-thread and can be a real PITA, especially if this is the first time it is being removed. If you don't have an air hammer or that does not work, one trick I learned from a friend who had grown up around airplane mechanics is to manually turn the engine until cylinder 1 is at the bottom of its stroke. Then, thread some nylon rope into the cylinder and compress it with the piston. This should keep the crankshaft from turning any further (if it does not, you need more rope in the cylinder!), and, you can now pop the bolt loose with a breaker bar, etc.
    2018 Subaru Crosstrek, 2014 Audi Q7 TDI, 2013 Subaru Forester, 1969 Chevrolet C20, 1969 Ford Econoline 100, 1976 Ford F250
  • mactavish2mactavish2 Member Posts: 3
    So, it is reverse thread? The guy working on this says he's never seen one that is reverse thread (on any car). Yes, he has an impact wrench.
  • xwesxxwesx Fairbanks, AlaskaMember Posts: 15,848
    No, I was mistaken... this bolt is not reverse thread! It has been about five years since I have pulled one off, so I checked a couple other sites for clarification. They all confirmed that it is not reverse thread.

    A couple other tips I found along the way:

    Easy way to remove the crank bolt:
    Get an ratchet/breaker bar that is long enough to go to the ground. Put the bar on the drivers side of the car on the ground. now, make sure it's on there good. Now, bump the starter. Don't actually start the car, but bumping the starter will loosen the nut in about a 1/4 of a second. Much easier to do than to do it by hand.

    You don't have to use the ground.

    I usually use the driver's side framerail (near the battery), space permitting. A typical 1/2" breaker can reach it
    2018 Subaru Crosstrek, 2014 Audi Q7 TDI, 2013 Subaru Forester, 1969 Chevrolet C20, 1969 Ford Econoline 100, 1976 Ford F250
  • fourthrowefourthrowe Member Posts: 2
    I ran into a situation like this on an acura (honda is notorious for tight crank pulley bolts). I eventually got a 3/4" drive setup with a 6' floor jack handle and supported the extension with a jackstand. As far as keeping the engine from rotating goes, I had the cylinder head off already so all I had to do was use the head bolts to jam something in to one of the pistons. When it broke loose I could have sworn that I had broken a connecting rod. I don't recommend the starter bump method because of the risk of damage to the flexplate/flywheel and starter. And the starter doesn't neccessarrily have the requisite torque to accomplish the task.
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