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View Full Version : Lost two altenator bolts (sheared right off)


rlivingood
08-16-2005, 07:24 PM
Folks,

Make sure you keep a look at your alternator bolts. This last weekend I had TWO shear right off. When I was putting in the plug I took a look at my serpitine belt connected to altenator since I was hearing squeaking the day before. The altenator was sitting on the bracket with just the tension bolt. The bracket was completely off the block. First word was ****.

Next word is how far was the Home Depot. Being 4 hours from home at Lake Oraville and 20 minutes from town there wasn't much of a choice. With $90 later (hammer, punch, corded drill to hook up to my invertor, drill bit, easyout, and a handfull of 3/8 bolts) we were round trip time and repair back to launch again in a hour.

Luckly the belt wasn't trashed. When I dropped off the boat for service this Monday, I asked to pick up a belt for a spare. Come to find this is a new boat 04 with 50 hours (got it in Sep 04) that the repair shop didn't even have them in stock yet. Doubt I'd been able to find a belt in Chico or Oraville.

Rod

bigmac
08-16-2005, 07:29 PM
Folks,

Make sure you keep a look at your alternator bolts. This last weekend I had TWO shear right off. When I was putting in the plug I took a look at my serpitine belt connected to altenator since I was hearing squeaking the day before. The altenator was sitting on the bracket with just the tension bolt. The bracket was completely off the block. First word was ****.

Next word is how far was the Home Depot. Being 4 hours from home at Lake Oraville and 20 minutes from town there wasn't much of a choice. With $90 later (hammer, punch, corded drill to hook up to my invertor, drill bit, easyout, and a handfull of 3/8 bolts) we were round trip time and repair back to launch again in a hour.

Luckly the belt wasn't trashed. When I dropped off the boat for service this Monday, I asked to pick up a belt for a spare. Come to find this is a new boat 04 with 50 hours (got it in Sep 04) that the repair shop didn't even have them in stock yet. Doubt I'd been able to find a belt in Chico or Oraville.

Rod


Apparently not an uncommon problem. I had the same two bolts shear off on my 2004 230VRS/MCX. Heard the squealing right before I was taking it in for first-service at 20 hours.

MrsJMT
08-16-2005, 07:32 PM
Us too, on our 04 209 last month.

Workin' 4 Toys
08-16-2005, 08:54 PM
2003 the exact same problem. I have heard of many on this site and others. Mine '03 MCX with about 100 hrs on it.
There are many threads on this recently. MC says it is Indmar not them.
Hmmmmm...... :mad:

caden
08-17-2005, 09:14 AM
What size bolts are these?
Boat is at the lake, and I will not be there untill Sat.
Seems like I may need a few of these for the spare parts box.
I have a 2003 P/S 209 w/MCX.

jrhollow
08-17-2005, 09:26 AM
A couple of weeks back I had the same problem on my 03 X-2 with 150 hrs. The bolts broke and the belt came off while I was running it. Good thing for the ear busting alarm or I would have been SOL.

One of the bolt stubs was loose enough where I could turn it out with my fingures. The other need a little help from a hammer and chisle to get it started. If they would have broken off without a little stub, I would have been in trouble. V drives don't have that much room on the backside of the engine.

When I replaced the bolts I went from a grade 5 bolt to an 8. Did anyone else do this? or can think of a reason not to?

sizzler
08-17-2005, 09:58 AM
i'll check my nuts this weekend

djhuff
08-17-2005, 10:18 AM
happened to me too, only lost one, but the dealer replaced both anyway.

88 PS190
08-17-2005, 10:26 AM
Best to replace before they break, its far easier to remove the bolt beforehand than to mess around drilling out and backing out the stub.

Only disadvantage I could find of going too high in grade is that if something drastic were to occur the bolts are cheaper than the alternator or engine block. But definately a low grade issue. And I do believe indmar delivers longblocks to MC, so it is their problem.

bigmac
08-17-2005, 11:03 AM
This alternator bolt-breaking in the late-model Indmar's appears to be a widespread enough problem that I would pre-emptively replace my alternator bolts with grade 8's and torque them myself. To be prepared to replace them in the field would require not just the bolts and wrench, but also a belt, a drill and some Easy-Outs.

Theoretically, a grade 8 bolt should have a higher tensile strength than a grade 5, but if even grade 8's aren't torqued properly, it can lead to excessive cycling and therefore premature failure. One other factor that might be at play here is the widespread problem of counterfeit fasteners. Just because your bolts are labeled grade 8 doesn't mean that they were actually manufactured to those specs. Some companies, in an effort to save a few bucks, will accept what appears to be a fantastic deal on the huge quantities of bolts that they need to build their engines, only to find out later that, for example, their alternators are falling off of their engines due to fastener failure.

rlivingood
08-17-2005, 12:46 PM
i'll check my nuts this weekend
This thread is about working on the boat :D

AIRCANX09
08-17-2005, 01:56 PM
Ditto here. See other posts. I did call my M/C dealer and service called M/C. They are apparently aware of this issue, but are not prepared to do a recall/ service bulletin. Local service suggested changing from #5 to #8 bolts.

rshlmn
08-18-2005, 11:11 PM
I had the lower two bolts holding the alternator bracket shear off tonight on my '04 X30/MCX. I wish I had known about the problem sooner. It would be alot easier to replace than to repair. :mad:

erkoehler
08-18-2005, 11:53 PM
I had the lower two bolts holding the alternator bracket shear off tonight on my '04 X30/MCX. I wish I had known about the problem sooner. It would be alot easier to replace than to repair. :mad:


Welcome to the board, and sorry to hear about your misfortunes :(

JDK
08-19-2005, 12:38 AM
Are these bolts too weak or are they too long?
A bolt holding a bracket will break off if it bottoms out in the block (not enough tension through the bolt's shank and the vibration of the bracket fatigues it).
The shear strength of a grade 5 bolt (or Cl8.8) is approx. 93,000 psi. I find it hard to believe an alternator bracket can exert enough force to shear 2 of these bolts off.

phecksel
08-19-2005, 09:30 AM
This alternator bolt-breaking in the late-model Indmar's appears to be a widespread enough problem that I would pre-emptively replace my alternator bolts with grade 8's and torque them myself. To be prepared to replace them in the field would require not just the bolts and wrench, but also a belt, a drill and some Easy-Outs.

Theoretically, a grade 8 bolt should have a higher tensile strength than a grade 5, but if even grade 8's aren't torqued properly, it can lead to excessive cycling and therefore premature failure. One other factor that might be at play here is the widespread problem of counterfeit fasteners. Just because your bolts are labeled grade 8 doesn't mean that they were actually manufactured to those specs. Some companies, in an effort to save a few bucks, will accept what appears to be a fantastic deal on the huge quantities of bolts that they need to build their engines, only to find out later that, for example, their alternators are falling off of their engines due to fastener failure.
That was the problem on my 87 Tristar, the bolt was marked grade 8, but file soft.

Better go check the 03 197 bolts :(

Leroy
08-19-2005, 09:37 AM
This falls in the category of why does this happen to my MC and I never hear of a car with alternator bolts breaking........

bigmac
08-19-2005, 09:52 AM
This falls in the category of why does this happen to my MC and I never hear of a car with alternator bolts breaking........


My guess is that General Motors buys their engine fasteners from a different place than Indmar.

Workin' 4 Toys
08-19-2005, 03:40 PM
This falls in the category of why does this happen to my MC and I never hear of a car with alternator bolts breaking........
Because they use spring tensioners. Not manual adjustments. You have to adjust these belts by feel. With a serp. belt, it does not forgive like a v-belt would. Why would a recall be announced when people are fixing them themselves. And there is no solution but to put a spring tensioner on it. And who is going to foot the bill for that, right? And I would think if there was room for it, they would be on there.

Workin' 4 Toys
08-19-2005, 03:42 PM
My guess is that General Motors buys their engine fasteners from a different place than Indmar.
Just a different means of tightening the belts. Look at how a GM belt is tightened, not by hand....

rlivingood
08-21-2005, 01:25 AM
Well I spoke with another friend that had this happen to his boat (actually only lost one of two) and he upped the bolts to grade 8. His recommendation is "DONT". Guess he lost one again and said it was a real pain to get it out since the 8 was much much harder to drill to get the easy out into it. Also either he or someone else told me that the bolts are lots cheaper than blocks and brackets.

With all that said while my boat is in service they went ahead and swapped them to 8s. Guess I'll need to add this bolt sequence to my checklist at the begining of a trip.

Rod

PendO
08-21-2005, 01:35 AM
Are these bolts too weak or are they too long?
A bolt holding a bracket will break off if it bottoms out in the block (not enough tension through the bolt's shank and the vibration of the bracket fatigues it).
The shear strength of a grade 5 bolt (or Cl8.8) is approx. 93,000 psi. I find it hard to believe an alternator bracket can exert enough force to shear 2 of these bolts off.

Interesting observation ... can anyone with a broken bolt comment on length?

bigmac
08-21-2005, 01:55 AM
Interesting observation ... can anyone with a broken bolt comment on length?


Uh...longer is better??



.

JMT
08-21-2005, 10:41 AM
The broken bolts I took out were 1 1/2 inch stainless. I replaced with grade 5 bolts because some research on the web showed that 8s were hardened all the way through and could be brittle. The 5s were only partially hardened and rated better.

Leroy
08-21-2005, 12:56 PM
On the length, I just matched the length of the extracted and broken piece.

Workin' 4 Toys
08-21-2005, 09:19 PM
Here are the bolts I removed from mine. As you can see the overall length of the broken ones is about 3 1/2" inches and grade 5. I used Grade 8s that were roughly 3 3/4" long that fit perfectly and DID NOT bottom out in the holes.

Workin' 4 Toys
08-21-2005, 09:22 PM
And my wife says I keep everything just for sake of keeping it. Hah, it actually pays off sometimes. If it helps one other person, it was worth the save. I keep them in my file of broken parts. Just in case they are ever needed!;)

Workin' 4 Toys
08-21-2005, 09:26 PM
Well I spoke with another friend that had this happen to his boat (actually only lost one of two) and he upped the bolts to grade 8. His recommendation is "DONT". Guess he lost one again and said it was a real pain to get it out since the 8 was much much harder to drill to get the easy out into it. Also either he or someone else told me that the bolts are lots cheaper than blocks and brackets.

With all that said while my boat is in service they went ahead and swapped them to 8s. Guess I'll need to add this bolt sequence to my checklist at the begining of a trip.

Rod
If the bolts are fresh/new and not rotted at all, after they shear off or break, you can take a very sharp tool similar to an all and very hard. Take the tip of it at about a 45 degree angle and tap the outer edge of the broken bolt in a counter clockwise rotation and it should walk out. If there are no bound threads. This should work flawless if done properly. I can try and shoot a picture of what to do if I did not make it clear. Let me know. This method requires no drill, or drill bits. Which in turn means no metal shavings in the boat.

Workin' 4 Toys
11-29-2005, 11:52 PM
Bringing an old thread back to life I need to get this figured out before next season. I was just thinking about it when I looked under the hood of a Corvette.
Anyone see a TSB on it, or anything similar to it from MC or Indmar?

Brn85ss
11-29-2005, 11:59 PM
Have you thought about using studs instead of bolts. Might be worth a try.

Engine Nut
11-30-2005, 12:36 PM
I am going to tell you as much as I know about alternator brackets and broken alternator bracket bolts. We have gone through several alternator bracket changes but here is the scoop on TBI and MCX through the 2004 model year.

The photo that I have attached shows the original front alternator bracket on the left. That bracket had spacers welded on and it attached to the engine with two long bolts. Over time, those bolts could flex and fail.

The bracket on the right is the replacement bracket. There were no spacers welded on therefore the attaching bolts were shorter which reduced the possibility of the bolts flexing. After initial release, the bolts used with the new bracket were changed to stainless steel. For the most part, the new bracket and the stainless steel bolts properly tightened resolved the issues. The new bracket is available as a kit which includes the stainless steel fastners and washers. The kit P/N is S495122. The stainless steel fastners should be torqued to 40 foot pounds.


Engine Nut

Leroy
11-30-2005, 12:51 PM
There was a recall for my era boat and the dealer replaced the bracket and bolts, about 50 hours ago. Mine failed at 50 hours, I replaced just the bolts to keep going in the summer, and then took to dealer in the winter to do this.


Way to go WFT, don't forget to remind her about how you helped with those saved broken bolts!

lakes Rick
11-30-2005, 03:50 PM
Engine Nut,

Is this an MC part # to be purchased thru the dealer?? thanks

Workin' 4 Toys
11-30-2005, 08:48 PM
Way to go WFT, don't forget to remind her !

It must be my short term memory, but who is "her"?

Workin' 4 Toys
11-30-2005, 08:50 PM
I am going to tell you as much as I know about alternator brackets and broken alternator bracket bolts. We have gone through several alternator bracket changes but here is the scoop on TBI and MCX through the 2004 model year.

The photo that I have attached shows the original front alternator bracket on the left. That bracket had spacers welded on and it attached to the engine with two long bolts. Over time, those bolts could flex and fail.

The bracket on the right is the replacement bracket. There were no spacers welded on therefore the attaching bolts were shorter which reduced the possibility of the bolts flexing. After initial release, the bolts used with the new bracket were changed to stainless steel. For the most part, the new bracket and the stainless steel bolts properly tightened resolved the issues. The new bracket is available as a kit which includes the stainless steel fastners and washers. The kit P/N is S495122. The stainless steel fastners should be torqued to 40 foot pounds.


Engine Nut
EN,
What length bolts are used? And is this 100% the resposibility of the owners to buy and replace? That you know of?

skin6599
11-30-2005, 09:16 PM
Here's a new one. I picked up a 2004 197 Tournament Team and half way through the summer the belt started scream'n at me. We check it out and found the alternator resting on the block. Got back to the cottage and pulled it apart and the only mark on the tension bracket was in the furthest position, like it was torgued at the factory and broke then. We replaced the stainless bolt and could only get it about half way up the tension bracket.

The earlier questions about size. I think it was a 7 or 8 mm stainless and I bought two!

Reported it to the dealer and they looked at me like I was crazy....

Workin' 4 Toys
11-30-2005, 11:12 PM
The earlier questions about size. I think it was a 7 or 8 mm stainless and I bought two!

Reported it to the dealer and they looked at me like I was crazy....
What is this about 7 or 8mm?

And I am still rethinking this stainless bolts. They are going to be one mutha F'r to get out if "they" break. Grade 8 is not good enough I ask myself? They can at least be drilled and extracted. Stainless is great for snapping extractors and stripping threads.

Engine Nut
12-01-2005, 08:12 AM
Your MC dealer can get the part for you. That is a valid P/N for MC or Indmar.

Engine Nut

Engine Nut
12-01-2005, 08:15 AM
EN,
What length bolts are used? And is this 100% the resposibility of the owners to buy and replace? That you know of?

The bolts are 3/8-16X1 1/2" and 3/8-16 x 1 1/4".

EN

Workin' 4 Toys
12-01-2005, 10:08 AM
The bolts are 3/8-16X1 1/2" and 3/8-16 x 1 1/4".

EN
Thats alot better than the 3 1/2" bolts that broke off.

Workin' 4 Toys
12-26-2005, 03:26 PM
I am going to tell you as much as I know about alternator brackets and broken alternator bracket bolts. We have gone through several alternator bracket changes but here is the scoop on TBI and MCX through the 2004 model year.

The photo that I have attached shows the original front alternator bracket on the left. That bracket had spacers welded on and it attached to the engine with two long bolts. Over time, those bolts could flex and fail.

The bracket on the right is the replacement bracket. There were no spacers welded on therefore the attaching bolts were shorter which reduced the possibility of the bolts flexing. After initial release, the bolts used with the new bracket were changed to stainless steel. For the most part, the new bracket and the stainless steel bolts properly tightened resolved the issues. The new bracket is available as a kit which includes the stainless steel fastners and washers. The kit P/N is S495122. The stainless steel fastners should be torqued to 40 foot pounds.


Engine Nut
MYMC,
Can you PM a quote on this part?
I think I may replace mine, even though I replaced the grade 5's with grade 8's on the factory bracket. I have a feeling I should change it anyway.
I have an '03 w/MCX

André
12-26-2005, 03:31 PM
W4T
I saw it quoted by "The Legend" in another alt bracket thread.Less then 50$ i think...

Workin' 4 Toys
12-26-2005, 03:37 PM
W4T
I saw it quoted by "The Legend" in another alt bracket thread.Less then 50$ i think...
Was that your $ or ours?

André
12-26-2005, 03:39 PM
Real money!
US dollars.
Let me try to fing that post for you.

André
12-26-2005, 03:49 PM
http://www.tmcowners.com/teamtalk/showthread.php?t=6245
Here you go.