Alternator bolts shearing off?

[Beausdad]

I've had all sorts of problems with my 4.6 4x4 XLT. I've replaced my intake gaskets and the intake manifold. I had a new A/C system put in last year. Then after all of that the alternator bolts just sheared off sending the thing into the fan. I had the fan replaced and I had someone remove the sheared off bolts, recap the holes for larger bolts and then reinstall. Same damn thing happened today. Both bolts sheared off. Everything appears to spin freely so I don't know what the problem is. Any ideas?

 

[Onuma]

Wow...that sounds pretty bad.

Is it possible your serpentine is out of alignment -- maybe causing too much tension on the whole system -- with the alternator bolts being a sort of "weakest link", so to speak? Just speculation.

When was the last time you had your pulleys and/or tensioner arm worked on?

Hopefully someone with a better idea comes along.

 

[Beausdad]

I honestly don't know. I didn't think all of those pulleys could get out of line. I guess I will find out once I get it towed. With 186K miles I should just cut my losses.

 

[Bobmbx]

Thats really unusual. Bolts are normally quite strong and only shear when subjected to large shear force impulses or when weakened by corrosion or other chemical exposure.

I gaurantee the belt is weaker than a steel bolt or any of the pulleys. Do you happen to have the bolt heads still? If so, post the numbers on the top of bolt here, or a picture.

Chinese crap bolts (fraud) are known to get into the supply system from time to time. We found some bolts on our submarine that were marked as being high yield K-Monel (marked with "dot-K-dot". Turns out they were more like nickel.

 

[jpopper]

Sounds like the bracket that bolts to the intake manifold and alternator is missing. I have worked for Ford for almost 20 years, I have never had one break the alternator mounting bolts unless that bracket was missing. Sounds like it may not have been put back in place after the manifold got replaced.

 

[Beausdad]

[MENTION=280055]jpopper[/MENTION], I don't recall there being a supporting bracket for the alternator. I pulled the intake manifold off twice, replacing it the second time. That would make perfect sense seeing that it is the downforce of the belt pulling on the alternator that is making this happen.

 

[Number4]

Only picture I could find online.

 

[lincolnshibuya]

There's also 2 sizes of alternator brackets supplied by Dorman (if this is your replacement intake manifold) one fits the mustang (and others) while the other is for the explorer.Make sure it's the correct one.

 

[rocco123]

I have a bracket that came from dorman when I replaced my intake. I don't have a use for it if u end up needing it.

 

[Beausdad]

So after reading jpopper's post last night I racked my brain trying to remember a bracket. I thought, " if this hasn't happened before the first time, then there had to be a bracket on top to deter the downforce." I specifically remember telling my wife," I must have done it right, I didn't have any parts left over." Then I remembered my two sons, 8 and 3, were out there while I was working. I had all the parts on the ground in the order I took them off. I recalled finding a metal "U" shaped object on the garage floor a few weeks later and throwing it in my toolbox not knowing what it was. Apparently one of my sons had picked it and moved it when I wasn't paying attention. It was a year between the first time it broke and this time and I drive the thing everyday. Never even crossed my mind. Took the bracket by the shop today and asked the guy to wait till I was gone before he told his mechanics, " you won't believe what this idiot did..." Thanks for the help guys. This is why I love this forum. It has saved me hundreds of dollars.

 

[jpopper]

Don't feel bad, even after 27 years of turning wrenches I still have blundering moments.

 

[Beausdad]

The way I see it is that even though I made this blunder, by doing the work of installing my own intake gaskets and then replacing the intake manifold later, I still saved myself about a $1000 as taking that intake in and out twice is a pricey job. Even with this blunder having to get fixed twice.