Broken starter bolts

Starlight · Jan 13, 2021

Hey guys, Capt.T here. Sharing this story in hopes it helps someone. Love my HMMWV and she "works for a living". As some of you know I have a support organization for returning wounded and disabled, Palm Beach Troop Support. The HMMWV is front and center at all functions and we love her but ...

She was parked out front and my wife jumped in to move her to the garage one day. She turned the start lever after the wait light went out and bam ! Big spark flies out what she described was the dash area, large clunk sound ! She runs and gets me. I ran out not thinking too much and see there's smoke coming from the rear. I grab a rench to disconnect batteries asap. At this point I tell her to grab extinguisher. I was disconnecting cables when the smoke turned to fire. Finally got the cable off, jumped under and extinguished fires in rear. Thanks God fires out and stayed there for a bit to make sure nothing else happened.

Here's what happened: Starter bolt/s sheared off. Starter comes lose. Hot cable hits the body. Parking brake gets hot and arcs out cables. Cables catch fire. Fire put out

Question: Why nothing else damaged ? Why did the shunt not give ?

Next event : Drill out broken starter bolts and easy out. First one a breeze. Second one was hell. Went through 3 expensive drill bits, and here's why. The last guys broke off a tap ! Then I guess he said the hell with it and left just one bolt and the old school support to hold this heavy ass starter. What I eventually removed was a broken tap ! That's why I went through the bits, it wasn't a bolt after all.

Anyway, hope this helps and I would love to know if anyone has been through anything similar . There are a lot of folks here with broken starter bolt issues but I don't see anything where the starter landed on part of the body and grounded itself until fire. And again, the did the shunt hold ??

Be safe and God bless this great country, Capt.T/ Palm Beach Troop Support

Action · Jan 13, 2021

Starlight said:
Hey guys, Capt.T here. Sharing this story in hopes it helps someone. Love my HMMWV and she "works for a living". As some of you know I have a support organization for returning wounded and disabled, Palm Beach Troop Support. The HMMWV is front and center at all functions and we love her but ...

She was parked out front and my wife jumped in to move her to the garage one day. She turned the start lever after the wait light went out and bam ! Big spark flies out what she described was the dash area, large clunk sound ! She runs and gets me. I ran out not thinking too much and see there's smoke coming from the rear. I grab a rench to disconnect batteries asap. At this point I tell her to grab extinguisher. I was disconnecting cables when the smoke turned to fire. Finally got the cable off, jumped under and extinguished fires in rear. Thanks God fires out and stayed there for a bit to make sure nothing else happened.

Here's what happened: Starter bolt/s sheared off. Starter comes lose. Hot cable hits the body. Parking brake gets hot and arcs out cables. Cables catch fire. Fire put out

Question: Why nothing else damaged ? Why did the shunt not give ?

Next event : Drill out broken starter bolts and easy out. First one a breeze. Second one was hell. Went through 3 expensive drill bits, and here's why. The last guys broke off a tap ! Then I guess he said the hell with it and left just one bolt and the old school support to hold this heavy ass starter. What I eventually removed was a broken tap ! That's why I went through the bits, it wasn't a bolt after all.

Anyway, hope this helps and I would love to know if anyone has been through anything similar . There are a lot of folks here with broken starter bolt issues but I don't see anything where the starter landed on part of the body and grounded itself until fire. And again, the did the shunt hold ??

Be safe and God bless this great country, Capt.T/ Palm Beach Troop Support

Did the hot wire hit the body or the frame?
The shunt is not a fuse or fusible link.
This is a good reason why folks should do a thorough inspection of new to them vehicles.

Coug · Jan 13, 2021

sounds like just plain bad luck combined with a less than adequate inspection.

As for the DC shunt, it isn't a fusible link, it will do nothing to stop current flow in the case of a shurt circuit.

The below taken from http://www.cromptonusa.com/DC Shunts Theory.pdf

DC Shunts:
Direct current instrument shunts are used to extend the range of ammeters whenever the current to be measured is too large to be passed through the instrument--usually currents over 50 amperes. The shunt, therefore, is a diverter which is used to "shunt" the majority of the current around the indicating instrument. Essentially, the shunt is a specially-designed resistor which delivers a millivolt output (to a millivolt meter or instrument) in proportion to the current flowing through the resistor

Starlight · Jan 14, 2021

Action said:
Did the hot wire hit the body or the frame?
The shunt is not a fuse or fusible link.
This is a good reason why folks should do a thorough inspection of new to them vehicles.

Thanks for that . It hit the frame. I know the shunt is not fusible link but thought is that much power going through it would at least stress it a bit. It's odd to me though that only the parking brake cables were caught on fire. I can't see where the hot could hit just the parking brake rod . What are your thoughts of some sort of large inline fuse to prevent this in the future (hoping not !) I'm installing the new upgraded support. I read a lot of folks having problems breaking bolts but don't see where anyone caught fire . That's hard to believe the way the starter is jammed in a tight spot. Thanks, Capt.T

Starlight · Jan 14, 2021

Starlight said:
Thanks for that . It hit the frame. I know the shunt is not fusible link but thought is that much power going through it would at least stress it a bit. It's odd to me though that only the parking brake cables were caught on fire. I can't see where the hot could hit just the parking brake rod . What are your thoughts of some sort of large inline fuse to prevent this in the future (hoping not !) I'm installing the new upgraded support. I read a lot of folks having problems breaking bolts but don't see where anyone caught fire . That's hard to believe the way the starter is jammed in a tight spot. Thanks, Capt.T

Yes, guess I should have looked that area over better. Been under her a bunch in the last 4 years and never saw a missing bolt in starter. Maybe someone cover there ass and just but the "head in". Be that as it may after I look at the pics perhaps there was chafing on the emergency brake line jacket and it was touching frame. When the frame was energized so went the brake line and thus the fire ?? Will put her back together soon. Thanks for the input guys

Edis06 · Jan 14, 2021

The starter bolts are a VERY common problem. Both of mine snapped back in June. I had the updated bolts installed with Loctite and I paint marked them. Checked them regularly. Then when replacing the balancer this week, I noticed that one of the two now was sheared and missing again! Also, the forward support nut was finger loose again.

Best advice is to replace the support hook with the updated hook and regularly check the nut tightness along with your crank bolt and half shaft bolts. Do it at each oil change interval. Also, paint park the starter bolts to facilitate an easy checkup so you don't forget.

I have now ordered new starter bolts from MME along with the updated hook.

TOBASH · Jan 14, 2021

As mentioned, you need to go over our truck top to bottom.

After 3 years I’m still doing that.

I’m about to exchange my harmonic balancer bolt on my 6.2 for the longer unit and torque it down tight to prevent known issues.

Besst of luck!

Starlight · Jan 14, 2021

Edis06 said:
The starter bolts are a VERY common problem. Both of mine snapped back in June. I had the updated bolts installed with Loctite and I paint marked them. Checked them regularly. Then when replacing the balancer this week, I noticed that one of the two now was sheared and missing again! Also, the forward support nut was finger loose again.

Best advice is to replace the support hook with the updated hook and regularly check the nut tightness along with your crank bolt and half shaft bolts. Do it at each oil change interval. Also, paint park the starter bolts to facilitate an easy checkup so you don't forget.

I have now ordered new starter bolts from MME along with the updated hook.

Great advice ! Thanks for the Paint Mark idea. Sounds like a lot of people going through this . Just installed the upgraded support

Starlight · Jan 14, 2021

Starlight said:
Great advice ! Thanks for the Paint Mark idea. Sounds like a lot of people going through this . Just installed the upgraded support

Starlight · Jan 14, 2021

All set, my girl is back together, new bolts, red locktite, new upgraded support. Fired right up. Don't know how nothing else was damaged but hey, all good ! Do you guys know of any threads talking about replacing parking brake cables ? Thanks for all the help guys ! P.S. It wasn't as "easy" as some said...lol

Starlight · Jan 15, 2021

Never mind on the brake cable replacement. Simple stuff. Thanks

Mogman · Jan 16, 2021

The reason the brake cables fried was because it was the one of the only paths from the frame back to the battery (through the body), When I stripped my #2 M998 I found no purposeful grounding of the frame, lots of grounds to the body and power pack but the body is sitting on rubber and so is the power pack.
You need to watch some things very closely in the future as the drive shafts were also a potential path, meaning you could have damaged u-joints and/or bearings in the transfer case and differentials, also the steering box and shaft was another possible path, that may have been the "flash" in the dash as there is a small wire grounding the steering shaft so the horn button will work.
Yet one MORE good reason to have a battery switch!

Edit, I was just looking at my #2 on the lift for possible paths, you should also inspect all the steel brake lines as that is another possible path from the frame to the body

Starlight · Jan 19, 2021

Mogman said:
The reason the brake cables fried was because it was the one of the only paths from the frame back to the battery (through the body), When I stripped my #2 M998 I found no purposeful grounding of the frame, lots of grounds to the body and power pack but the body is sitting on rubber and so is the power pack.
You need to watch some things very closely in the future as the drive shafts were also a potential path, meaning you could have damaged u-joints and/or bearings in the transfer case and differentials, also the steering box and shaft was another possible path, that may have been the "flash" in the dash as there is a small wire grounding the steering shaft so the horn button will work.
Yet one MORE good reason to have a battery switch!

Edit, I was just looking at my #2 on the lift for possible paths, you should also inspect all the steel brake lines as that is another possible path from the frame to the body

Many thanks for this !! Capt.T

Starlight · Jan 25, 2021

Ref: Right side (Passenger) parking brake cable replacement. Well, I spoke too soon thinking this would be a quick in and out job ...
Question for you guys. Do you have to pull the muffler to do this replacement ? As usual it's much appreciated. Can't seem to find much on it but did read where someone had to pull muffler. T

Ajax MD · Jan 25, 2021

Is there a bulletin or notice I can read about this starter bolt issue that i can read somewhere? How can i tell if my truck has this hook mod?

Action · Jan 25, 2021

Ajax MD said:
Is there a bulletin or notice I can read about this starter bolt issue that i can read somewhere? How can i tell if my truck has this hook mod?

Use the photos in post #9 and compare to what you have in your motor mount.
If the starter is in place, you may get your cell phone camera at the other end of the motor mount.
I dont recall seeing a wiring loom through it before, though.

Ajax MD · Jan 26, 2021

Action said:
Use the photos in post #9 and compare to what you have in your motor mount.
If the starter is in place, you may get your cell phone camera at the other end of the motor mount.
I dont recall seeing a wiring loom through it before, though.

The hook "inside" the motor mount is what I'm looking for? In the photo it doesn't look like anything is hung from the hook. Should there be?

Action · Jan 26, 2021

Ajax MD said:
The hook "inside" the motor mount is what I'm looking for? In the photo it doesn't look like anything is hung from the hook. Should there be?

the stud on the end of the starter sits in the hook. The started isnt installed in those pics.

Starlight · Jan 26, 2021

Action said:
the stud on the end of the starter sits in the hook. The started isnt installed in those pics.

Thanks for handling that Ajax ! Capt.T

Starlight · Feb 4, 2021

Finally removed the muffler and can now get to the emergency brake cable connections. Will also replace the emergency / parking brake sensor as it was fried during this ordeal. So far so good ...

Broken starter bolts

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