Alternator bolt broke off in head.

[sgms18]

In the process of tightening up belts i uncovered an old band-aid. The lower bolt on the passenger alternator has an old bolt broke in the hole maybe 1/4"-3/8" in. The stack of washers on the bolt head should have been a red flag. It was late, hot, long day Yada yada.... So I went on & stripped it out not knowing it was only holding on by 2-3 threads. Does anybody have a head laying around they can measure the hole depth on? I gota either drill the broken piece & try an ez-out or drill the whole thing install a helicoil. I have no idea how much bolt is still in the hole. Just don't want to run into the exhaust passage

 

[fitz]

I will get a measurement for you tonight after work.
I ran into this problem on my M1028.
I bought Harbor Freight right angle drill for $30 or $40 and some of their left handed drill bits. The left handed drill billts drill with the drill in reverse. They act as a screw extractor and when they catch the metal the screw comes right out (in theory atleast).
My bolt came right out & the right angle drill fit withought removing the radiator.

 

[sgms18]

Thank you. I've got a buddy that going to let me borrow his Snap-on extractor kit. Has left handed bits & ez-outs. Fingers crossed.

 

[cucvrus]

That head bolt hole looks like it was an issue in the past. Good Luck. A welder and a pointed bolt may work. A bit tricky but can be done. Careful Slow and Steady. No rush job.

 

[sgms18]

This alternator bolt looks to metric. Does that sound right? I don't have a pitch gauge handy but the thread diameter measures .387. I'm really surprised it's not 3/8-16

 

[cucvrus]

You are correct. It is M10 x 1.5 metric thread. All the bolt holes with the exception of the bell bolts are metric. The bell bolts are 3/8" x 16. I have attached a picture of a past repair to the same bolt. They must have lost the correct long bolt. They threaded one into the head and a nut and bolt on the bracket. They backed the bolt out of the head and locked it against the alternator bolt. The genius. I corrected this with the correct bolt. I make the spacer with Black pipe nipple if I have none available. I was short at the moment. Good Luck.

 

[fitz]

I measured that hole at 15/16" deep.
On a side note, that bolt was already broken off on my truck when I bought it. Someone just ran a bolt through the bracket/alternator/bracket and put a washer & nut on the back side. The alternator was not supported on the engine side. I ran the truck like that for 10k miles before the bracket cracked (who knows how long it was like that before I bought it).
Had I known it was a 20 minute fix, I would have fixed it right away.
Let us know how yours turns out.

 

[sgms18]

Thank you for checking it man. I made some drill guides to take advantage of the couple threads i got left & hopefully overcome the already off center drilling attempt.

 

[sgms18]

Got the peice of bolt today. Once I got me a hole drilled in it an ez-out took it right out. Thank God!

 

[fitz]

Nice job, glad it worked out.

 

[rmesgt]

I thank God for every day. I am happy your broken bolt was an easy fix. I think I will try to find some of those centering gizmo's. I have never seen them before. A metric and SAE set would be a great accompany kit for my tap and die sets.