M998 Alternator Mount Broken Bolt for a NOOB

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MNINENINEEIGHT

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While poking around under the hood I noticed significant slack in the alternator mount and have since found, of the three bolts holding it to the engine block one is broken one is missing and the other was out of the block but trapped in-between the power-steering pump reservoir.

The aluminum bracket has a crack in it. I have looked online unsuccessfully to find a replacement. Will the steel 200 amp upgrade mount work with my 60amp alternator?

Broken bolt. any tips on removing the broken bolt from the motor? I have a speed out kit. Don't want to mess up the block obviously. Where can I get the replacement bolts? I tried getting some at Home Depot but with the broken and missing ones I dont know the correct size.

IMG_20191103_232550.jpgIMG_20191109_122911.jpgScreenshot_20191109-144901.jpg

Thanks for the help, I got my 91 M998 6 months ago and have done a few minor repairs but this is the first big one.
 

papakb

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Drill the bolt and then use your easy out kit to remove the broken bolt. There's a really good video on You Tube about removing bolts in sunken places. Tractor Supply has the best selection of grade 8 hardware in this area now that Lowes wiped out Orchard Supply. There's also a good video about how the stop drill and repair cracked castings on You Tube.
 

donkren

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IMG_20191111_125508321.jpgIMG_20191111_125521610.jpgIMG_20191111_125536661.jpgI think this is what you need. It came off my M998 which didn't come with an alternator, so I can't be absolutely certain. But it looks like the one in your pic to me, and I'm pretty sure it is the right part. I put on a 200A in it's place, so I had to change out this mount. In this box, USPS ground looks like it would cost 16.70 to ship. If there is a flat rate box that will ship it cheaper, I'll use that, but I don't have that info. 'Want me to send it?
 

86humv

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View attachment 782567View attachment 782568View attachment 782569I think this is what you need. It came off my M998 which didn't come with an alternator, so I can't be absolutely certain. But it looks like the one in your pic to me, and I'm pretty sure it is the right part. I put on a 200A in it's place, so I had to change out this mount. In this box, USPS ground looks like it would cost 16.70 to ship. If there is a flat rate box that will ship it cheaper, I'll use that, but I don't have that info. 'Want me to send it?
Thats the one.
Its aluminum.....there is a Steel version for a 100 amp also.
 

Bulldogger

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If the bolt broke due to vibration, and wasn't wrenched in half due to being stuck by corrosion, you might be able to tickle it out with a pick/punch, hitting it CCW as though twisting it out. This sometimes work if the bolts aren't frozen in. Can't say it'll work for sure since I don't know how yours broke.

An EZ Out is also a good idea, but may be hard to do because of other stuff in the way of getting a drill and left-hand thread bit in there.

Best of luck!

BDGR
 

TOBASH

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If the bolt broke due to vibration, and wasn't wrenched in half due to being stuck by corrosion, you might be able to tickle it out with a pick/punch, hitting it CCW as though twisting it out. This sometimes work if the bolts aren't frozen in. Can't say it'll work for sure since I don't know how yours broke.

An EZ Out is also a good idea, but may be hard to do because of other stuff in the way of getting a drill and left-hand thread bit in there.

Best of luck!

BDGR
I have used a Dremmel to cut a slot across the top and then use a flathead screwdriver. Otherwise reverse drill and reverse easy out.

Best,

T
 

papakb

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They do make left twist drill bits that you could use for situations like this. If the snag or bind up they're turning the way you want things moving to unscrew the bolt. Definitely soak it with penetrating oil before you start.
 

MNINENINEEIGHT

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If the bolt broke due to vibration, and wasn't wrenched in half due to being stuck by corrosion, you might be able to tickle it out with a pick/punch, hitting it CCW as though twisting it out. This sometimes work if the bolts aren't frozen in. Can't say it'll work for sure since I don't know how yours broke.

An EZ Out is also a good idea, but may be hard to do because of other stuff in the way of getting a drill and left-hand thread bit in there.

Best of luck!

BDGR
I don't actually know how it broke but I think the other two bolts vibrated out and the last bold couldn't hold up the whole assembly and broke off.
 

MNINENINEEIGHT

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They do make left twist drill bits that you could use for situations like this. If the snag or bind up they're turning the way you want things moving to unscrew the bolt. Definitely soak it with penetrating oil before you start.
That bit is cool! I saw that in the youtube videos but Tractor Supply and Home Depot did not carry one.
 

MNINENINEEIGHT

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Thanks Everybody!!! for all the advice (and parts thx donkren) on this thread I got it fixed.

Details and pics for those interested. I made a template by doing a rubbing on a piece of notebook paper to get the hole placement. I affixed it to a piece of scrap aluminum with contact cement, and drilled out the two free bolt holes. I then used a punch to center a small enough hole to get the pilot hole started. I used a paint marker through the small hole to confirm the spot on the broken bolt. I removed the template to see the paint dot and it was pretty centered. I put the template back on for the first portion of drilling to keep the bit from moving and damaging the surrounding threads. The Eazy-out drill bit side was worthless and basically rounded off instantly (but the other side did get the bolt out).

I used an angle grinder to shorten a regular drill bit to fit in between the fan and the block. The bolt hole drilled out perfectly and it went all the way through almost instantly. I sprayed some WD40 in through the drilled hole and waited for 30min to help make removal easier. I had to widen the hole to get to the next size up on the easy out because it felt like the smaller one was flexing a lot and I didn't want it to break. I used a socket wrench to use the Eazy-Out to remove the bolt piece. I cheered out loud when it came out. Got it all reassembled and went for a drive. All seems to be working well. I might need to tighten the alternator belts because they were wobbling more than the PS belts. I was surprised that the power steering didn't need to be bled since I drained and refilled it to remove the assembly but so far working like normal. Thanks again!

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