Nov 6, 2012
77 C3
Hey guys.. Just pulled the vett out for the spring and realized that one of the alternator mount bolts was broken. The block has a portion broken away that most likely caused this. Any how... the threaded part is still in the hole. I drilled the bolt and inserted a thread extractor but the bolt does not want to budge! I am adding a LOT of pressure but Im terrified of breaking the extractor off inside the bolt.

What should I do??:(

Keep soaking the hole with penetrating oil 2-3 times a day for a week if necessary. It does take time to get good penetration. Break the extractor off and you have a BIG problem. I'm not a big fan of the spiral extractors, preferring the straight ones. If you are very careful and are so lucky as to drill the stud dead centre, you can keep opening up the hole to the root diameter of the threaded hole. Then you can remove the spiral threaded pieces with a scriber or a hooked too. SnapOn makes a set of tools with various shaped hooked ends that are great for fishing stuff out where fingers don't fit.
When putting a new stud in, make sure you get it as deep as you can. Three or four threads deep isn't enough. 1 1/2 times the diameter for bolt engagement minimum is a good rule of thumb eg. 3/8" diameter bolt should have 9/16" minimum engagement.
Thanks guys but I think theres more to it than corrosion. The bolt that broke off looks brand new. It was replaced a few years ago. After closer inspection it appears that the bolt did damage to the edges of the hole and threads. I think Im going to have to take a zippy cut and cut about 5mm off the block to get rid of the damaged thread area. I picked a bad time to leave my grinder at work:rolleyes:
Vettster.... If you have to go to that extent of damaging the head I think there may be another alternative? I believe there's a bracket available to mount on the exhaust bolts and provide the pivot for the alternator.
Or swap the passenger and driver heads?
I believe that hole bottoms out in the head casting. Sometimes people use a bolt that is too long?
Keith's idea is a good one.. Drill the hole bigger if you can.
Good luck.....
Thanks guys.. but I got er dun before reading your post. Not worried about cutting the head as I will probably have this car for life. ;)

As I suspected the damaged threads were holding it back and I zippied that area off. I also used a knereled bit on a dremel to help straighten out the drill hole. They cut very well. Just need to make a spacer now.

I think the comment about the bolt being to long and bottoming out in the casting is correct. I will make sure that I dont follow suit.

Cheers guys! Keep the rubber side down!:coolgleam:

Thanks guys!

That started off a long list of small problems to be fixed.

Leaking windshield fluid resavor. I think its the turtle neck
Passenger door that has suddenly decided not to open from the outside.
Floor pans. Not going all out on the pans. Just a patch job
loose this and that, that giggles and makes noise.
Reverse lights that wont come on.
New SOFTER shocks
new pads for the windows so they dont rattle when down a bit.
Windows are very slow to go down. Ive heard that cleaning the grease off helps?

If you guys have any advice on any of the above... Id love to hear it


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