Sheared harmonic balancer bolt

S

scdad&son

Registered User
My 1990 sc wont start. I thought it was the icm, but when I was testing circuits my son noticed a belt hanging down. Turns out the bolt for the harmonic balancer broke off about half inch below the head. Do I have to search for a new motor for this car?
 
It's repairable not easy or fun but you can get the broken piece out and replace the bolt and the HB as well as the crankshaft position sensor since that usually gets broken when the HB breaks
 
That was on my 90 was able to get the bolt out (wasn't easy) and I replaced it as well as the balancer and crank position sensor
 

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This is the sensor. The reason the bolt broke is the balancers dampener went bad and broke very common issue on these cars and stock balancers
 

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& hope that it didn't damage the key when the damper came off.
Otherwise you'll need to remove the front cover & timing chain to replace it, as it goes all the way back into the crank timing gear.
 
I was fortunate on mine the key wasn't damaged although I did pull the timing cover (I pulled the engine to fix this issue as well as multiple oil leaks including timing cover) but I can see how it could be done without removing the engine all though personally I felt much more comfortable having the engine out and being able to see in a straight line to ensure I didn't cause Damge removing the broken bolt
 
From what I can see, the sensor appears to be unharmed. But I think the hub is still on the shaft. How do I get that off?
 
You said the belt fell off, so the balancer must already be most of the way off.
Just use a harmonic balancer puller to get it rest of the way. If it didnt fall off the sensor likely is o.k.
 
DOUG H said:
You said the belt fell off, so the balancer must already be most of the way off.
Just use a harmonic balancer puller to get it rest of the way. If it didnt fall off the sensor likely is o.k.
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The balancer was actually loose and resting on the center of the crank, which is why I figured the sleeve broke. Thankfully it appears to have given out when I hit the key to start it up and it didn't hit the crank sensor. From what I can see it's undamaged so the super coupe gods are blessing me there.. If I could only find a new balancer I think I'd be set. I am curious to know if you Hagee any tips on how to keep that crank from turning when I try to extract the broken piece of the bolt...
Also, I would like to say that I really appreciate all of your advise. It's been very helpful.
 
scdad&son said:
The balancer was actually loose and resting on the center of the crank, which is why I figured the sleeve broke. Thankfully it appears to have given out when I hit the key to start it up and it didn't hit the crank sensor. From what I can see it's undamaged so the super coupe gods are blessing me there.. If I could only find a new balancer I think I'd be set. I am curious to know if you Hagee any tips on how to keep that crank from turning when I try to extract the broken piece of the bolt...
Also, I would like to say that I really appreciate all of your advise. It's been very helpful.
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Use a left hand drill and bit and it usually just turns right out easily, a bit half the size of the broken bolt, I raised the car and went underneath. I think I removed the rad fan
 
So, your balancer isn't damaged (that you can see) the bolt just broke off below the head & the h.b. just came out & fell off?
 
93-SC-TD said:
Use a left hand drill and bit and it usually just turns right out easily, a bit half the size of the broken bolt, I raised the car and went underneath. I think I removed the rad fan
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Yeah, I pulled the fan too. But the crank turns when I try to extract the bolt piece. How scan I immobilize th so I get enough pressure to turn out the stud?
 
Wow, it must be really jammed if it turns the crank? Wonder if its bottomed out in the crank-too long/wrong washer? May have to remove starter & jam ring gear if auto trans or just put in 4th gear if manual.
 
DOUG H said:
Wow, it must be really jammed if it turns the crank? Wonder if its bottomed out in the crank-too long/wrong washer? May have to remove starter & jam ring gear if auto trans or just put in 4th gear if manual.
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DOUG H said:
Wow, it must be really jammed if it turns the crank? Wonder if its bottomed out in the crank-too long/wrong washer? May have to remove starter & jam ring gear if auto trans or just put in 4th gear if manual.
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Auto. So I have to wedge the flywheel or something, right? Isn't there a cover panel at the bottom of the transfer.case I could.remove and then lock it down with a vise grip?
 
scdad&son said:
Yeah, I pulled the fan too. But the crank turns when I try to extract the bolt piece. How scan I immobilize th so I get enough pressure to turn out the stud?
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Crank shouldn't be turning, takes a lot to turn that especially with just a drill bit
 
scdad&son said:
Yeah, I pulled the fan too. But the crank turns when I try to extract the bolt piece. How scan I immobilize th so I get enough pressure to turn out the stud?
Click to expand...
Now you are trying to buy another complete engine? For another car/project you have or you found more serious damage?
 
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