Harmonic balancer broke off can you believe it!!

jmlr

Registered User
Well it looks like I have to pull and crack the engine seeing how the harmonic balancer broke about a 1/4 inch behind the front of the key & the bolt broke in the crank. Does't that suck. I figure while I'm at it I might as well do some mods. All is stock except the hollowed out cats & the k&N.

Any suggestions?

Thanks
 
harmonic balancer

it it not hard to remove as it first seems just get a set of ez out drill a hole in the bolt that is left in the crankshaft and use the ez out with a reverse drill to back the broken bolt out.the now to get the piece of balancer that is left on the crank shaft you are going to have to get aharmonic balancer puller the go to the hard ware store and get 3#8 sheet metal screws about 3 inches long.along with some washers then drill 3 small holes parallel to the shaft in to the remaing balancer then use the puller with the screws to pull the broken peice off .good luck .ihad the same problem last week on my 89 sc took me 1 hour to do the whole job
 
I can believe it too. Scary thing is I was watching the HB on my '91 wobble while I was waiting for the cooling fan to come on. I guess it is time for me to upgrade to a BHJ balancer before it snaps the head of the bolt off like yours did. I have been reading that they are a one time use item. Most people just reuse the old balancer after they have removed it for whatever reason (broken bolt, crank sensor replacement, etc..) and the HB does not fit tightly enough, therefore it wobbles. Something to that effect.

Dean Shirley is selling a brand new never used BHJ balancer for $350, his post seems to have disappeared from the Classifieds on TBSCEC so it may be sold.


You can go here to get more info on the BHJ and ordering info! The part number for a new bolt and washer can also be found at that link.
 
Last edited:
We get a rash of broken crank bolts and HB's all the time. In a month or so as the New group start racing around in their "new" SC's we will have a bunch of blown headgaskets from overheating. Happens every year.

Jeff
 
I broke three......

I can believe it, the stock balancers are crap. After breaking the third one, I decided that the BHJ was well worth the money. If you need any pointers on removing the broken sleeve and bolt, let me know.
 
Should we just replace the balancer as a proactive measure before it breaks? The owner I bought my SC from said the balancer went on what is now my car, and Ford could not rebuild the engine correctly so they just put a new one in. So the engine in my '90 SC has about 55,000 miles on it. Is this something I should be concerned about? Does driving style have anything to do with it?
 
While the balancer is not the greatest, I tend to think it's the bolt that is the worst part of the operation. It just isn't strong enough. There is a revised bolt used on the Mustang 3.8's that is a replacement for ours that is probably a good proactive replacement item if your balancer appears o.k.

I should have done mine when I had the radiator and accessory drive parts off, but I don't have an impact and time got tight.
 
Just so you guys know, the harmonic balancer and the pulley must be replaced as a unit or rebalanced as a unit, or you will break the balancer again. The bolt breaks because the balancer breaks not the other way around. When installing underdrive pulleys, you must remove ALL the balance pins in the rear of the balancer, because the pulley will be neutral balanced.

Jeff

You don’t need to replace the balancer, unless it is broken. It is a good thing to remove the pulley and check the rubber elastomer ring for cracks, over time it will dryrot and cause the outer ring to slip throwing the assembly out of balance and break the bolt off in the crank. You MUST reinstall the pulley in the same orientation (match mark them together so they go back together right), or guess what you will break it again.
 
soooooo :)

I can just replace the bolt on my unit (still in good shape) And I'm good to go>???
Lee
 
If the bolt broke I'll bet dollars to doughnuts that your HB is bad. You need to remove the pulley and take a look (note above).

Jeff
 
What Larry said. Like I said before the bolt breaks because of the balancer not the other way around.

Jeff
 
Back
Top