Broken Starter Bolt

[adf5565]

So somehow during the process of reinstalling my starter today one of the starter bolts broke. It was already installed and was cranking the motor over and when I got out of the truck I saw a bolt laying on the floor, it sheared off inside the block. Two questions, what size bolt are these (they don’t seem to be 3/8-16 thread) so I can order ones off McMaster carr. And 2 any good tips on removing the broken part in the block?

I’m taking the truck on a trip Wednesday morning so I don’t have much time to get the truck road ready.

 

[Mullaney]

So somehow during the process of reinstalling my starter today one of the starter bolts broke. It was already installed and was cranking the motor over and when I got out of the truck I saw a bolt laying on the floor, it sheared off inside the block. Two questions, what size bolt are these (they don’t seem to be 3/8-16 thread) so I can order ones off McMaster carr. And 2 any good tips on removing the broken part in the block?

I’m taking the truck on a trip Wednesday morning so I don’t have much time to get the truck road ready.

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Well that generally sucks...

Those are special bolts. The cross-hatch pattern is slightly larger than the rest of the shoulder part of the bolt. You should go to the local Chevy Dealer - or maybe one of the "HELP" sections in a local parts house to get a replacement.

Hopefully you have a left-handed drill bit that will reach up in the block and maybe is loose enough to back out the broken part. You might be lucky and it broke off "even" and you could possibly reach up in the block and tap it several times - maybe making a shallow slot that you might be able to use to back out the bolt.

KEY to all of this (once you get the old one out) is to test fit your new bolt. Making sure that you have the right length is pretty important. Chevy factory lengths are either long or short so it isn't like there are a bunch of different starter bolts. ALTHOUGH having shims - especially if you had them could be part of the problem too...

 

[adf5565]

Thanks for the reply. I have a cheap “speed out” remover which thankfully worked great. It was broken off up in the block but I was just able to reach it and back it out. So at least that part of the problem is solved!

That is a good point about the bolt lengths/shims. When I purchased the truck it had a starter shim in even though the starter itself says “no shim”. Last time I had the starter out to do the oil pan gasket I removed the shim and it still started fine. There were also 3 washers under the head of one of the bolts as it was slightly longer than the other, and that is the bolt that broke. So honestly it’s probably good it broke while I’m at home so I’m not stranded somewhere.

I did a quick search and found an old post that said part number GM 15544950 was for the starter bolt. Can anyone confirm that? I ordered a couple of them already just to give it a fighting chance to be here by Tuesday.

 

[Mullaney]

Thanks for the reply. I have a cheap “speed out” remover which thankfully worked great. It was broken off up in the block but I was just able to reach it and back it out. So at least that part of the problem is solved!

That is a good point about the bolt lengths/shims. When I purchased the truck it had a starter shim in even though the starter itself says “no shim”. Last time I had the starter out to do the oil pan gasket I removed the shim and it still started fine. There were also 3 washers under the head of one of the bolts as it was slightly longer than the other, and that is the bolt that broke. So honestly it’s probably good it broke while I’m at home so I’m not stranded somewhere.

I did a quick search and found an old post that said part number GM 15544950 was for the starter bolt. Can anyone confirm that? I ordered a couple of them already just to give it a fighting chance to be here by Tuesday.

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That is GREAT NEWS for sure! Yes sir, broke at home beats on the side of the road any day.

I don't have anything to prove that part number here.
Hopefully some of the other guys can chime in

 

[adf5565]

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That is GREAT NEWS for sure! Yes sir, broke at home beats on the side of the road any day.

I don't have anything to prove that part number here.
Hopefully some of the other guys can chime in

No worries, I appreciate the help. O’reilys has this listed as the bolt specs. So hopefully someone has a few extra laying around and can measure to confirm.

• Thread Size: M10-1.50
• Length (mm): 111mm

 

[cucvrus]

The thread size you have listed is correct. Metric is correct. Just get 6.2 diesel starter bolts and use an SAE washer. Just 1 washer or if you are lucky, you will get flange bolts.

 

[Valor]

So somehow during the process of reinstalling my starter today one of the starter bolts broke. It was already installed and was cranking the motor over and when I got out of the truck I saw a bolt laying on the floor, it sheared off inside the block. Two questions, what size bolt are these (they don’t seem to be 3/8-16 thread) so I can order ones off McMaster carr. And 2 any good tips on removing the broken part in the block?

I’m taking the truck on a trip Wednesday morning so I don’t have much time to get the truck road ready.

And make sure you install the bracket, brace on the nose of the starter for support. That is important.

 

[GunnyM1009]

15544950 is the correct starter bolts. I was chewing up starters until I replaced my Flexplate so I've ordered several sets of them.

 

[cucvrus]

15544950 is the correct starter bolts. I was chewing up starters until I replaced my Flexplate so I've ordered several sets of them.

Do you have the starter support bracket in place. That support bracket is one of the most important parts on the starting system.

 

[GunnyM1009]

Do you have the starter support bracket in place. That support bracket is one of the most important parts on the starting system.

Yes I was chewing up the gear due to busted up teeth on the flexplate

 

[adf5565]

15544950 is the correct starter bolts. I was chewing up starters until I replaced my Flexplate so I've ordered several sets of them.

Awesome, thanks! The bracket is also installed so I’m good there, I’ll confirm those bolts are still tight once I install the main starter bolts as well just to be sure.

 

[adf5565]

The new bolts arrived today so I reinstalled the starter. Cranked it over for a few seconds with the injector pump disconnected as well as started the truck normally a few times just to test it out a little bit. So far so good so hopefully that problem is in the past!

 

[Mullaney]

The new bolts arrived today so I reinstalled the starter. Cranked it over for a few seconds with the injector pump disconnected as well as started the truck normally a few times just to test it out a little bit. So far so good so hopefully that problem is in the past!
View attachment 874892

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Hoping that you had a trustworthy friend that could work the key for you - while you were under the truck - to "lay eyes" on the starter while engaged... Just to make darn sure that there isn't any "starter wiggle" happening?

I went back and saw that you said that the rear support is on the end of the starter too? Almost certain I saw that...?

 

[adf5565]

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Hoping that you had a trustworthy friend that could work the key for you - while you were under the truck - to "lay eyes" on the starter while engaged... Just to make darn sure that there isn't any "starter wiggle" happening?

I went back and saw that you said that the rear support is on the end of the starter too? Almost certain I saw that...?

Yep bracket is in place and also set my phone up to take a video from underneath when I started it. Both locations I ordered the bolts from came in on time so now I have a few extras as well.

 

[Mullaney]

Yep bracket is in place and also set my phone up to take a video from underneath when I started it. Both locations I ordered the bolts from came in on time so now I have a few extras as well.

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Amazing how the phones today are almost like having an extra hand... GOOD PLAN using it in video mode to watch what was happening under the truck. Heck, you might find yourself a new job as the Safety Man for some big company with that idea. Need to create an App for that!

 

[INFChief]

So somehow during the process of reinstalling my starter today one of the starter bolts broke. It was already installed and was cranking the motor over and when I got out of the truck I saw a bolt laying on the floor, it sheared off inside the block. Two questions, what size bolt are these (they don’t seem to be 3/8-16 thread) so I can order ones off McMaster carr. And 2 any good tips on removing the broken part in the block?

I’m taking the truck on a trip Wednesday morning so I don’t have much time to get the truck road ready.

Those bolts break very easy. Not too hard to get out. They’re standard GM starter bolts. You should check the bendix engagement and shim the starter if needed.

 

[ezgn]

Those bolts break very easy. Not too hard to get out. They’re standard GM starter bolts. You should check the bendix engagement and shim the starter if needed.

It's my understanding that the starter bolts are designed to break under extreme conditions to protect damage to the block.

 

[nyoffroad]

It's my understanding that the starter bolts are designed to break under extreme conditions to protect damage to the block.

That doesn't always work.

 

[INFChief]

It's my understanding that the starter bolts are designed to break under extreme conditions to protect damage to the block.

If there’s something going on that high up that breaks those starter bolts then there’s bigger problems to worry about. Those starter bolts will break it over-tightened or reused too many times. No one uses a torque wrench - they get them German torqued (guten tight).

 

[edpdx]

Went through it two weeks ago. Looks like you got it back in right. Great job. Thanks for sharing.