Pully to balancer bolts

scbird1

Registered User
Should these be the hardend steel [black] bolts or the silver softer metal bolts? The reason I ask is with the new under drive pullys and bhj balncer you dont get the bolts. The guy who had the car before me just threw all the bolts into a can only half made it though and bolted it all back up with what ever he had. I have both types allready. Thanks
 
I used the shiny bolts, bought them at auto zone. Then when they either came loose or whatever they broke off at the heads and sent my pulley flying off the crank. I got the balancer off and tried to drill out the old bolts but it was too much of a pain in my *** so I got another balancer. I am 99% sure that I went to a hardware store and bought grade 8 bolts this time around, I also used a little bit of blue loc-tite (vibration resistant) on the bolts to keep them from walking loose after a while.

I don't know whether the cheaper bolts just broke from the stress, or had been walking loose over time causing a wobble. I think they were walking loose because I had a noise down there the day before this happened. I changed my oil and looked but couldn't see anything loose. I SHOULD have checked the bolts on that pulley but I didn't. Next day on the way home from work it snaps off and throws the belts. Luckily my pulley was laying on the front sway bar and the belt serp belt didn't slice through the hoses. I did however loose the jackshaft belt, never found it. I replaced the belt, new balancer, and grade 8 bolts, put it back on, and have been trouble free for over a year now.

The cheap bolts I had in there only lasted about 6 months. I'm 99% sure they walked out, but for a few dollars more, get the stronger bolts.
 
What I have are all stock bolts from Ford but not sure if you need hardend steel or not. I put the softer ones in thinking the hardened steel ones would be more prone to snaping and have no give but i may need to rethink this one. Dose anyone know what grade of bolt was stock?
 
I realy need to know the answer to this as I dont like to take chances. If someone could back one out of a motor thats sitting around and take a look at it I would be very greatfull. All the bolts shering off a balancer on a rebuilt engine is no fun. If the bolt has a number on it I would like to know also.
Thanks, Mark
 
I just pulled a pulley off my motor so I looked at the bolts. They are stamped 10.9 on the head. That's approximately Grade 8.

I've seen these grade of metric bolts available at local hardware stores. They usually have one of those pull out things that says "Metric - Automotive" that contains metric flanged bolts.
 
Balancer pulley to damper bolts info. and pics from my 89 SC.

From my original balancer: (left in pic)
Head size= 13mm
Thread size= M8 x 1.25(pitch)
Under head length= 30mm
Bolt markings= (see pic) number 10 in center (grade) of bolt and a symbol to the left that looks like a letter C with a small H inside it (manufacturer symbol ?).
Bolt made of= ??

From my balancer bought 4yrs ago -from Ford: (right in pic)
Head size= 13mm (notice larger head cap size)
Thread size= M8 x 1.25(pitch)
Under head length= 30mm
Bolt markings= (see pic) number 10.9 (grade) and letters EX (manufacturer symbol ?) in center of bolt.
Bolt made of= ??
 

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Wow, now thats what I call good information. This is one area you dont want to install the wrong bolts in. As it turns out I had the wrong bolts in there so this is another example of a perfect SC community. The good part is the engine is still on the stand so no harm no foul. Thank you guys. Mark
 
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