HELP - CUCV Breaking Starter Bolts Often

[Disciple]

I've had a persistent and increasingly annoying problem with my CUCV snapping the Grade 8 Starter Bolts about every 2 months of daily driving. At first I think it was because the last shop that replaced my starter didn't use shims and it got loose somehow.

I've had to replace the starter bolts about 3 times now in the last 6 months. Each time the bolts are breaking off just below the threads, leaving the threads inside the block. The last time it happened it actually stripped the threads out of the block and I had to drill out the hole, tap it, and I used a Heli-Coil, which I assumed was holding well enough.

I haven't had a chance to look in the hole yet to see if the Heli-Coil is still there and in good shape, but I'm really wondering what is causing this to continue to be an issue. The starter was properly shimmed, correct Grade 8 bolts from O'Reilly's, and the support bracket was in place and tight. I don't get it.

 

[porkysplace]

Have you tried genuine GM starter bolts and not the china bolts the auto parts stores sell ?

 

[Disciple]

Not yet, but I sure will be now. That is, of course assuming that the Heli-Coil isn't all messed up and I don't have to get into a really imaginative fix.

 

[85CUCVtom]

The GM bolts are worth every penny. I keep extras in the tool bag in my truck. They are sold in packs of 5 I believe.

 

[Disciple]

The GM bolts are worth every penny. I keep extras in the tool bag in my truck. They are sold in packs of 5 I believe.

Ok great. I'll give them a shot. They certainly can't be any worse than what I've been dealing with. Apparently "Grade 8" doesn't mean the same thing in China as it does here. Pretty sure it translates directly to "cheap junk, guarantee you break most inconveniently causing much sorrow and scratching of head".

You wouldn't happen to have a GM Part Number for those handy, would you?

 

[Hasdrubal]

Search...I found some AC Delco bolts online for $1.60 ea. Bought 4, 2 for spares. In 2006 when I rebuilt my starter, I re-used the original bolts and hand tightened them. Didn't know they should not be re-used or the torque value, They held up, looked fine when I rebuilt starter again this year. Used lock-tite this time as a preventative measure.

Part # 15544950

 

[Disciple]

Search...I found some AC Delco bolts online for $1.60 ea. Bought 4, 2 for spares. In 2006 when I rebuilt my starter, I re-used the original bolts and hand tightened them. Didn't know they should not be re-used or the torque value, They held up, looked fine when I rebuilt starter again this year. Used lock-tite this time as a preventative measure.

Part # 15544950

Thanks. Will do. I'll ask the dealer what torque spec should be too. I've also just been hand-tightening and I have been known to break a bolt or twenty by hand when tightening. I have also been using Loc-Tite every time because I assumed, like every other bolt on this truck, it would eventually rattle itself out.


UPDATE: Had the wife run my tools out to me (I know better, they're usually in the truck but I'm rebuilding a motorcycle and left them in the garage) and was able to tighten up the one remaining bolt (it was also Loc-Tite'd, but loose) enough to get a decent bite on the flywheel and got 'er started. Drove it home and parked it until I can get to it. Looks like it was the driver's side bolt that snapped (again). Broke off at exactly the same spot, just below the threads, inside the block. Looks like the Loc-Tite could be part of the problem too. I'm guessing that the bolts are rattling loose over time, enough to let the starter slam into the cheap bolts and break them. Or I could just be over-tightening crap metal bolts and they can't stand up to the torque of the starter and THEN the other bolt gets loose. I don't know.


The one that broke is the one I used the Heli-Coil on so I'm crossing my fingers that I won't have to over-bore everything and jimmy-rig it together with bigger bolts. That's certainly an option, I'm just worried about weakening the starter housing and then THAT starts cracking.

 

[jdknech]

the reason the grade 8 bolts keep breaking- grade 8 bolts are very hard, and they dont take any "flex" so when to starter flexes the bolt enough times, it snaps.. the factory bolts on the other hand- allow it to flex some, and not break.. hopefully your Heli-Coil is fine, and the factory bolts get you back on the road..

 

[Disciple]

Just ordered the stock GM bolts directly from AC Delco. Pack of 5 was about $15, plus another $15 for 2-day shipping. A little steep for a few bolts but I need to get this thing back on the road and if this stops the breakages, its worth it. This way I'll have 3 spare bolts that I hope I'll never need. Thanks for the help guys.

 

[doghead]

Not sure how may times this has happened to you but, it should help to use the GM bolts, and the correct torque.

Be sure the front support bracket is tight as well.

 

[TacticalTruck]

Be sure the front support bracket is tight as well.

I'd be willing to bet he doesn't have the front bracket and that's why they're breaking.

Jeff

 

[porkysplace]

I'd be willing to bet he doesn't have the front bracket and that's why they're breaking.

Jeff

Read the 3rd paragraph of post # 1 he said he has the bracket on and tight.

 

[Disciple]

Read the 3rd paragraph of post # 1 he said he has the bracket on and tight.

True and correct. In one of my previous adventures down this road I noticed that the support bracket was missing a bolt. I figured out which bolt size and thread it needed and when I went to replace it, discovered why it was missing. The threads in the block were stripped. So, I got to go back to the parts store for ANOTHER tap and eventually got a bigger bolt in place and tight. This time, all the right parts were in all the right places and it still broke the starter bolt. So, that was two different bolts with stripped threads that I got to fix, one for where the bracket attaches to the block and one for the driver's side starter bolt. Yippee!

Oh. And it was February. In Minnesota. In an un-heated garage. Laying on the concrete at 3 am by the time I finished. I can think of a few more enjoyable experiences. Like maybe swimming with jellyfish or laying on a fire ant hill.

The GM bolts should be here in two days and I'll update on my fix when I get it finished.

 

[bigginstactical]

I know you have the bracket but is it the right one? I just figured I would ask. I have gear reduction starter but they left the direct drive bracket on. I replaced it and put new GM bolts in as extra insurance. Hope you get it figured out! best of luck!

 

[Disciple]

Wow. Never thought about that. Excellent question, I have no idea. I'll have to compare pictures of the two brackets when I get under there. My starter is the smaller gear reduction also. When I put it all together everything seemed to fit fine but I'll have to verify that somehow. Thanks!

 

[bigginstactical]

http://www.steelsoldiers.com/showthread.php?59357-Starter-BracketThis link should help. Part way down shows the two different brackets.

 

[319]

TM -20 says torque is 33 ft lbs (45 Nm).

 

[Disciple]

Man, you guys are awesome. Didn't even have to pretend to do a search then ask anyway
Love this community!

 

[Disciple]

Ok, it's well known that I'm a little bit of a dummy at times. I thought I had the gear reduction starter and got worried when I discovered that I had the older style, curved support bracket but it turns out I have the Direct Drive starter, P/N 6346. I did a SEARCH (gasp!) to figure this out all on my own!

I guess this is good AND bad news. If I had been running the wrong support bracket it would have made me feel better about the longevity of my fix after changing it, but now all I have to blame is Chinese bolts and (not likely) possibly poor mechanics work on my end. Oh well.

Bolts should be here tomorrow and I'll have it ready to throw back in as soon as they get here. Thanks again everybody!

 

[Disciple]

Alright! Finally all wrapped up. I have the correct AC Delco bolts, thread-loc'd with lock washers, torqued to 33 lb. ft. with the support bracket on and tight, and one shim in place. The first time I started it up, I don't think it has ever sounded that clean and smooth starting before, so I'm hoping this is the LAST TIME I have to go through all of this. Thanks for everyone's help.