Alternator adjustment bolt ... not the L kind - PeachParts Mercedes-Benz Forum

BodhiBenz1987 · #1 01-07-2010, 01:45 AM

... The adjustment bolt on my alternator in the 240D is stripped, so I bought a new one. It's not the L-shaped type, but a straight bolt with a gear collar around it that slides the alternator side to side when you turn it (http://www.allpartsexpress.com/item.wws?sku=MBZ082741&itempk=68162&mfr=Genuine&weight=0.25). Any tips on how to remove it? I took the nut off and tried to push it out but it won't budge. I'm guessing I just need to remove the air filter housing and hit it a little harder, but I thought I'd ask first in case there's some obvious step I'm missing, such as removing the alternator from the bracket.

layback40 · #2 01-07-2010, 06:00 AM

Just make sure there isnt thread in the bracket it goes through & the nut is a lock. I have memories of having to unscrew a bolt. A long time ago & it might not have been on the Benz. Old age must be getting to me!!

BodhiBenz1987 · #3 01-07-2010, 12:38 PM

Quote:

Originally Posted by layback40

Just make sure there isnt thread in the bracket it goes through & the nut is a lock. I have memories of having to unscrew a bolt. A long time ago & it might not have been on the Benz. Old age must be getting to me!!

Only the tip of the new bolt is threaded, but I'll check to see that the threads don't overlap the dimensions of the hole it goes through. I know I'm gonna have to take the air cleaner off ... not that big a deal, but the little things seem so much more strenuous when it's 20 degrees and very windy out.

toomany MBZ · #4 01-07-2010, 12:43 PM

I would loosen item #'s 170, 251 and 227 first.
I watched someone make this adjustment from under the car, he didn't remove the air cleaner housing.

BodhiBenz1987 · #5 01-07-2010, 12:49 PM

Quote:

Originally Posted by toomany MBZ

I would loosen item #'s 170, 251 and 227 first.
I watched someone make this adjustment from under the car, he didn't remove the air cleaner housing.

Thanks for the breakaway pic ... I did loosen all the nuts (and removed the one on the geared bolt). I wonder what #209 is and if that has anything to do with it. It's pretty easy to access the big bolt with everything intact, just not much leverage to knock it out.

daw_two · #6 01-07-2010, 01:12 PM

Quote:

Originally Posted by BodhiBenz1987

Thanks for the breakaway pic ... I did loosen all the nuts (and removed the one on the geared bolt). I wonder what #209 is and if that has anything to do with it. It's pretty easy to access the big bolt with everything intact, just not much leverage to knock it out.

As I recall, #209 is sleeve that the bolt goes thru. I don't recall the purpose. I replaced an alternator on my FIRST 300D.

Billybob · #7 01-07-2010, 01:25 PM

You mention the geared adjuster bolt being stripped; I assume you mean its bolt head is stripped? I will also assume then that this geared adjuster bolt will not turn! You have the nut removed from its end and it will still not turn?

What has most likely occurred is the steel bolt shaft has corroded and fused to the alternator’s alloy frame mounting ear. That is possibly why the head would get stripped also! You may be able to remove the bolt in situ by using heat/penetrant/hammer methods; it will likely take patience more than anything, as brute force will not work. If it where me I would remove the alternator from the car and work on it. The dangers with this particular problem is “mushrooming” the bolts threaded end making it impossible to drive it thru and out of the alternator frame from too much hammer application or in the alternative using too much “hammer” and breaking the entire alloy alternator frame mounting ear off with the bolt still securely seized in place!

With the part off the car you can do all the things that might help much easier and effectively, and in all likelihood that will ultimately be necessary anyway. So don’t waste too much time trying to get lucky and have it just “pop out after a couple hits” it might, but it’s more likely to not happen that way!

Once you get the new bolt installed get a spare socket and then grind down the socket opening so that you get the maximum of the female hex portion of the socket in contact with the bolt head's male portion. The way the geared bolt head is constructed and the way a socket does not have its working surfaces extending completely to the outer edge of its opening, in effect set up a circumstance where less than full contact is made between the parts to which torque is applied and the result is often a stripping/rounding of the bolt head.

If you ever get the opportunity upgrading to the later style L-shaped bolt tensioner configuration is a project with a happy, useful result! Good Luck!

BodhiBenz1987 · #8 01-07-2010, 01:30 PM

Quote:

Originally Posted by Billybob

You mention the geared adjuster bolt being stripped; I assume you mean its bolt head is stripped? I will also assume then that this geared adjuster bolt will not turn! You have the nut removed from its end and it will still not turn?

What has most likely occurred is the steel bolt shaft has corroded and fused to the alternator’s alloy frame mounting ear. That is possibly why the head would get stripped also! You may be able to remove the bolt in situ by using heat/penetrant/hammer methods; it will likely take patience more than anything, as brute force will not work. If it where me I would remove the alternator from the car and work on it. The dangers with this particular problem is “mushrooming” the bolts threaded end making it impossible to drive it thru and out of the alternator frame from too much hammer application or in the alternative using too much “hammer” and breaking the entire alloy alternator frame mounting ear off with the bolt still securely seized in place!

With the part off the car you can do all the things that might help much easier and effectively, and in all likelihood that will ultimately be necessary anyway. So don’t waste too much time trying to get lucky and have it just “pop out after a couple hits” it might, but it’s more likely to not happen that way!

Once you get the new bolt installed get a spare socket and then grind down the socket opening so that you get the maximum of the female hex portion of the socket in contact with the bolt head's male portion. The way the geared bolt head is constructed and the way a socket does not have its working surfaces extending completely to the outer edge of its opening, in effect set up a circumstance where less than full contact is made between the parts to which torque is applied and the result is often a stripping/rounding of the bolt head.

If you ever get the opportunity upgrading to the later style L-shaped bolt tensioner configuration is a project with a happy, useful result! Good Luck!

Thanks! Another advantage of taking the whole alternator out would be the ability to take it inside to work on it ...

. The bolt does turn ... it's just very hard to get a purchase on, and it doesn't turn easily ... so it's probably stuck in there pretty good.

kerry · #9 01-07-2010, 01:57 PM

I've taken one out. My recollection is that #209 was tight to the bolt. It would spin for the adjustment but was difficult to slide off the bolt. I'd try some penetrating oil. You may also need to drive the bolt thru 209 from the back towards the front with a drift.

BodhiBenz1987 · #10 01-07-2010, 02:13 PM

Quote:

Originally Posted by kerry

I've taken one out. My recollection is that #209 was tight to the bolt. It would spin for the adjustment but was difficult to slide off the bolt. I'd try some penetrating oil. You may also need to drive the bolt thru 209 from the back towards the front with a drift.

Given my past experiences with this car, I'm guessing the bolt and that sleeve are one now.

Billybob · #11 01-07-2010, 02:53 PM

Quote:

Originally Posted by BodhiBenz1987

Given my past experiences with this car, I'm guessing the bolt and that sleeve are one now.

Yes, that is also very likely if the bolt turns! You can obtain a new spacer or with the alternator on the bench, grind the head off the bolt and as much of the shaft inside the adjuster slot, grind the opposite threaded end off the bolt and as much of the shaft inside the adjuster bracket. Then you can lever the alternator and the spacer out of the bracket, the remaining bolt shaft can then be removed from the spacer much easier in a vise and reused. You've got to get the old bolt and spacer out even if you had a new bolt and spacer.

BodhiBenz1987 · #12 01-07-2010, 03:25 PM

Now I can't get the bolt that holds the top bit of the bracket out. Cripes. Guess I'll have to find my torch ... I think it's at my dad's shop on the other side of town.

yellowbenz · #13 01-07-2010, 03:49 PM

You have to loosen the bolt on the attachment to the block that will allow the adjustment arm to pivot. The spacer cylinder will be a challenge to replace but without it you won't be able to tighten the alternator without deforming the bracket. Might have to wiggle the alternator to get that bolt out. I found it easier to turn the star bolt from the front. Used a torque wrench for the extra length. Make sure the belt is not in the way. This could
be blocking the bolt. It is a pretty easy thing to do once you've done it three or four times. I wish I could say Ive only had to do it once.

yellowbenz · #14 01-07-2010, 03:58 PM

Quote:

Originally Posted by BodhiBenz1987

Now I can't get the bolt that holds the top bit of the bracket out. Cripes. Guess I'll have to find my torch ... I think it's at my dad's shop on the other side of town.

Don't take out 230, just loosen it. 200 and 155 have to come out . Loosening 230 will allow 176 to pivot . This will facilitate tightening the belt with the star bolt (200) as well.