Sheared generator bracket bolts.

[Coug]

When I first got the truck(m1123, 200 amp generator) the stud on the exhaust that holds the rear generator bracket was sheared, and a couple of the front bolts were loose.
It started making noise again, so I checked, and the exhaust stud is sheared again, and at least one of the front bracket bolts has the head popped off of it.

I am not sure what this happened. I torqued everything to spec when I replaced the stud last time.
Anyone have any ideas or seen this happen repeatedly before?

Anyway, I looked up the dimensions of all the bolts and the stud holding the bracket, and have replacement bolts in grade 12.9 on order. Hopefully they take care of the issue so it doesn't happen again.

On a slightly related note, will the overrun clutch for the post 196900 serpentine belt system work in place of the earlier solid pulley on the generator? No idea if it's related to the failure, but I figure taking any stress I can off the mounting bolts can't hurt.

 

[Action]

Did you have the spacer on the long bolt at bottom of alt/gen?

 

[Milcommoguy]

There is another / option heavy duty bracket (like 7/16 ? inch thick) that mounts below the exhaust to a boss on the engine block. Might look into that set up.

Something is ?? out of round / balance. Might check for a cracked mounting cradle too.

Shake, rattle and rip, CAMO

REAR SUPPORT BRACKET 12342074 Double check P/N to be sure.

 

[Coug]

There is another / option heavy duty bracket (like 7/16 ? inch thick) that mounts below the exhaust to a boss on the engine block. Might look into that set up.

Something is ?? out of round / balance. Might check for a cracked mounting cradle too.

Shake, rattle and rip, CAMO

REAR SUPPORT BRACKET 12342074 Double check P/N to be sure.

View attachment 844694

Not seeing any cracks or anything.
That's the part number for the rear bracket that is already on my truck. I think mine is slightly twisted as it's holding the remains of the stud at a slight angle, so I'll order a replacement just to be sure.

 

[Coug]

Did you have the spacer on the long bolt at bottom of alt/gen?

I see a spacer in the parts breakdown image that looks pretty big, but no part number for it. Also not seeing how/where it would fit on here, as there is no free space at all between the mounting tabs and the bracket spacer. My UOC os NNN.

Later in the parts manual there is a spacer/washer for the 200 amp install, but it doesn't show UOC NNN

 

[Milcommoguy]

Not seeing any cracks or anything.
That's the part number for the rear bracket that is already on my truck. I think mine is slightly twisted as it's holding the remains of the stud at a slight angle, so I'll order a replacement just to be sure.

Sorry about the bad PN. Had it marked ??? Now that you say that... the HD one has a tab on it for PS hose I think. Don't make me go and look LOL

IMO... If trying to tie into the exhaust bolt "again" I would hunt down the HD support strap. Those angles to the exhaust are a little off for "real support" IMO.

Watch out for spacer too. That's a good way to bust tabs on alternators if left out.

Day and night difference, CAMO

 

[Coug]

Sorry about the bad PN. Had it marked ??? Now that you say that... the HD one has a tab on it for PS hose I think. Don't make me go and look LOL

IMO... If trying to tie into the exhaust bolt "again" I would hunt down the HD support strap. Those angles to the exhaust are a little off for "real support" IMO.

Watch out for spacer too. That's a good way to bust tabs on alternators if left out.

Day and night difference, CAMO

yeah, I found the part number for the longer bracket in the ECV parts manual (12460273), going to order that instead of the one on there. I figure even if the longer one doesn't work for some reason, I can use a torch to twist the existing one into shape so it's more flat (out of the truck; I learned that lesson already with a propane torch and brakes)

Hopefully someone else can help confirm that some models don't have the spacer in there, as I can't find a number for one anywhere in the parts manual that shows the UOC for my truck.

 

[Action]

The heads and exhaust may be in slightly different positions between n/a and turbo models. If you can find a parts list from a 200 amp install kit, that should have the correct items listed.

 

[Retiredwarhorses]

what serp setup do you have? New or old style?

 

[Coug]

what serp setup do you have? New or old style?

old style.

 

[Hammer]

Your more than welcome to come look at both of mine side by side and look for any differences, measurements, etc. One of each flavor.

 

[Coug]

Your more than welcome to come look at both of mine side by side and look for any differences, measurements, etc. One of each flavor.

where does the rear support bracket go on the one with the new style setup? Is it a long one down to the block or short one to the exhaust stud?

 

[Hammer]

Ha, no idea. Will have to look.

 

[86humv]

Any truck with a serp system supposed to have the Long to the block bracket...the short one should only be on a 60 amp truck.

 

[Coug]

Any truck with a serp system supposed to have the Long to the block bracket...the short one should only be on a 60 amp truck.

in the parts manual the pre 196900 serial number shows bracket to exhaust stud. Post 196900 appears it should be the longer one

 

[Hammer]

I have 200 amp alts in both mine. One has the older serp belt setup, and it bolts to the exhaust.
Other one has the overrun on the alt, and the heavier bracket that goes further down to the block.

 

[Coug]

Hammer's trucks also invalidate the "Pre/Post 196900" parts breakdown, as both are 182xxx trucks; just one got the newer serp setup during rebuild.

 

[Milcommoguy]

Motorpool Sgt. "Just slap it back together and get it out of here"

It's a HumV, CAMO

 

[86humv]

Looked at early and late manual...early says: 200 amp V belt and 100 and 200 amp Early surp uses little bracket.
Late manual says use long bracket and does not ref. little bracket for same Early surp system.

 

[Retiredwarhorses]

where does the rear support bracket go on the one with the new style setup? Is it a long one down to the block or short one to the exhaust stud?

remote mounted PS reservoir serp setup uses the one that goes to the engine block.
just an FYI, there is more than one of those support bars..IIRC, the bar for a 60amp won’t fit without modifications
if reusing on a 220amp-belt truck, that’s why the 200am kit comes with its own support bar in the kit.