97 blazer 4.3 v6 auto 4x4. 240k

about 3 yrs ago replaced the starter and found one broken mounting bolt. original starter. the bolt was rusted at the break so it had been broken for a while. this past week no start. starter was whining. crawled under and the other bolt is now broken. ( should have fixed it right on the first break, now i have two to do.) as soon as i get the electrics off of the starter i an going to attempt a repair by center punching and drilling w a carbide bit. if a no go, call the big hook for a tow. at least it is in my driveway.

questions? is this a common problem? what size bolts are original? 3/8- 16 or metric? if i do get the thread part out i will chase it w a tap. any tips or suggestions?

great forum, thanks

bernie

 

Not a common problem. I would look at the end of the first broken bolt and see why it broke. A spiral look to it would indicate that it was overtightened or twisted off sometime during removal. Otherwise if it had more of a wedge shape I would suspect it was work hardened by moving side to side which is unlikely. I would guess the second bolt failed because it was left with double the work. Good luck and get those bolts replace. 3/8 sounds like an acceptable guess.

 

thanks for the reply. both bolts are spiral breaks, at the base of the thread. today i got the starter out to make room to work. started to drill with a new 3/8 hss bit to get a starter dimple on the bolt. can't get a center punch in there and swing a hammer. i sprayed it w penatrant. next time i will start w a small diameter carbide bit and work up to a larger easy out. i think i will put in a new starter. what a pita getting the old one out.

bernie

 

started drilling. kissed both bolts w 3/8 hss bit (new) to get a dimple the other day. today using cutting oil and a variety of bits. snap on left hand drills, right hand carbide and a hss. all new all 1/8 " in dimple. not much luck. stopped after an hr, way to cold outside even at 29 degrees(a warm day this winter).

I think part of the problem is lack of space to push the drill. first i used a 3/8 dewalt vs reversible drill. can only get at one bolt. switched to a smaller older 1/4" rockwell drill with a smaller nose. 2k rpm. Is this to fast for drilling??? what is the right speed to drill??

after i warmed up i found in the garage a jacobs chuck w a stud in it. i think i will chuck it in the drill and try to drill with more leverage. also thinking about using a spade bit extension the get into the bolt area. as it stands now i will never reach the second broken bolt wo an extension of some sort.

i have the front tires about a foot off the ground on blocks. the rear wheels are on the ground. maybe i will have to raise the rear also.

any thoughts on how to do this. maybe i just have to push harder??? really don't want to break a bit.

thanks,

bernie

 

Good luck, I have a stripped lug nut that has been that way since last fall..
has been too cold to get off.
the key to this, is a good strong bit, lots of wd-40 to keep it cool as you are drilling, and lubricated.

 

Sorry Bernie, I'm a small guy so space isn't an issue I worry about. I would have started out by attempting to weld a nut to the exposed bolt, but that's just because I have a welder in the corner. After that, try to make the bolt flat using a dremel or small grinder otherwise the bit is going to try and walk or not drill straight. Follow that with a center punch and something small like an 1/8 bit. From there you can go larger.

Correct me if I'm wrong but don't wheel studs just press out? All the ones I've done

 

All the wheel studs I've done press out so a good couple hits with a large hammer knock them out. No drilling or hard work required.

 

correct on wheel studs, but not my post.

my starter bolts are broken off below the surface level of the bell housing. they broke off where the thread meets the shank of the bolt, which is recessed by 3/8" below the bell housing. not possible to weld, even if i had a welder andknew how to use it!!!!!!

thanks.

bernie

 

You're down to drilling them out or using an easy-out. Since it's recessed it sounds like a 3/8 transfer punch would start it in the very center. Good luck though.

 

some good news. inboard bolt is out. the easy (access) outboard bolt is being stubborn. used a spade bit extender ( two set sctews holding left hand drill bit) walked the broken bolt right out. started on the easy (access)one but not so easy. next try w be w an 1/8" bit then jump up to 3/8" to catch the steel and turn it out. if i were 40 years younger i would be done by now. older and colder don't mix as well as they used too.

bernie