617 Alternator Bracket with Buggered threads
 

The PO had someone replace the alternator. It appears that they buggered up the threads in the lower mounting hole in the bracket, towards the front of the engine. Although there are a number of ways to tackle this problem, I thought I'd get on the forum and look for some collective wisdom!
You can use a standard metric tap to clean the threads up front the front of the engine, but run the risk of mis-aligning the tap. Another approach is to go from the back of the bracket and this has the advantage of keeping the tap in the correct alignment for the thread bore, but using a standard length tap in not long enough to allow you to turn the tap. A 150 mm length tap is available but cost prohibitive and located in England. There is a third alternative and that is to weld a hex bolt to the tap giving it enough length to slide in from the back of the bracket. I wonder if you guy's have any other ideas ?

Back in my younger days, I had the same problem with a 616. I fabricated a small bracket and attached the front bolt to the bracket made and the other side to another bolt somewhere.

Be careful, as in teh 616, the front bolt hole is machined clear through the block, and a worked out bolt will spew oil all over the place. (Happened to me en route to the coca cola 600 some 30 years ago,,,)

Thanks mespe, actually my post is mis-marked for this is a 616. My bad.... Ok, I was trying to tap this hole with the bracket still on the engine, but how easy is it to take off ?

I don't remember the removal of the bracket to be all that difficult on my N/A OM617 - must be the same part as the OM616. I'd certainly remove the bracket if it looks like it will let you!

My vote is to see if you could get away with a heli-coil. Littlest amount of change to the existing set up.

Thanks Stetch, I agree with removing this. Maybe I read something wrong (wouldn't be the first time) for I thought the harmonic balancer needed to come off to remove this.
The bolt is M10 * 1.5. The hole in the bottom of the alternator is elongated and is starting to take the shape of an eclipse. If I can get the mount off, it will make fixing this soooooo much easier !

Well if you can get the bracket off with the balancer still fitted - I didn't think of that to be honest - it would be good. So long as the hole isn't too oval you might get away with it as you need a bigger pilot drill size for an insert.

if there is no difficulty getting the bracket off, it'd be easier to just get one from a junkyard and swap them...

lemme know if you have difficulty getting it off, or finding one.

As I remember is just some easy to, get to, 17mm bolts.

If a suitable replacement bracket was not something I had on hand, I would heli-coil that sucker and get on with my life.

Ever get this figured out?


I have the same problem with my 300SD. The bottom bolt evidently sheared and left some of itself threaded into the bracket and some in the part that goes through the alternator.

While trying to pry it out, thinking that it was just stuck I ended up with a two piece bracket :)

The four bolts on the side of the block are easy enough to remove, but the one in front is a royal pain and it looks like removing the balancer is the only way to get access.

You do not have to remove the balancer to get to the front Bolt.

Turn the crank by hand with a 27mm deep socket. turn it clock wise IE to the right standing in front of the engine.

The balancer has about a 2" cut out. line this up with the Bolt and you should be able to get it out. The bolt is about 1 3/8" long.

I have an engine on a Stand and removed the bracket w/o removing the balancer etc... I just put the bracket back on a couple days ago, not if I can just find that bolt............:cool:


Charlie

What did you use to remove it?



I tried a wrench, socket, and crows foot and did not have the space to do it.



I did line up the cutout in the dampner and remove the fan and pully too.


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