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  #1  
Old 09-12-2008, 06:34 PM
johnbonds
 
Join Date: Sep 2008
Location: Mount Pleasant SC
Posts: 56
Alternator replacement. 1982 240D

When I returned home after a six weeks' absence, the '82 240D battery was down. While charging it overnight, I checked the alternator belt tension and found that the alternator was torqued on the pivot bolt, was out of line and wobbling on the pivot. The belts had been changed in May '08, incident to a shop replacement of the vacuum pump, so they are new.

I got a replacement rebuilt alternator, on a "lifetime guarantee" from my local parts store that sold me the unit 12 years ago. It appears identical, and they moved the alternator cooling fan and pulley from the old to the new. Paid $10 for the freight. So far so good. I bought a new adjuster plate and bolt to go on the new unit, as the old adjustment extension on the bolt head was bent (yep, I did it). Discovered that I couldn't remove the adjuster plate without taking the whole aluminum casting off the engine block, to which it bolts, as the attachment bolt (head to the rear of the engine) doesn't have room to be removed due to interference. So, that came off and was cleaned while waiting for parts.

Finally, all in hand, so attached the adjustment bracket to the aluminum casting and bolted that to the engine. Then with a new bolt attached the new alternator to the bottom of the mounting casting (the old bolt had been worn almost halfway through, which caused that misalignment and made the mounting hole in the old alternator oblong instead of round). Couldn't get the alternator belt on, even with the alternator pushed all the way in. So, took out the bottom (pivot bolt), torqued the belt onto the pulley, and tried to install the bottom pivot bolt. No go. Couldn't get the holes to line up. I tried every trick I knew to get that thing lined up, including cutting the old pivot bolt (worn halfway through) and using it to screw into the attaching casting from the front, hoping to line the holes up so I could then start threads from the back. Nope. So, alternator back off to get the belt loose, and then remounted the alternator with the bottom pivot bolt. Next to get the belt on, did the old trick of putting the belt on the crankshaft and alternator, and pulling it along the top of the water pump pulley as far as I could, then cranked the engine briefly to get the belt on.

OK, now the alternator is on, and the belt's attached. Time to put the adjustment bolt, spacer, washers and nut on the adjustment bracket. Nope. The alternator is pulled tightly up under the adjustment bracket, with no play, and I can't get the adjustment bolt to line up with the hole in the upper alternator "ear." In fact, the belt is tight enough to run the alternator nicely with no adjustment bolt installed. But that leaves it floating on that bottom pivot bolt, and the bracket is pushed up against the cooling water fitting at the back top end of the bracket. Vibration will probably break that fitting. So I don't want to run it.

The drive belt is the 13 x 1030 size specified for the car, and it appears to be too short for this application (or this alternator). I don't want to take all the belts off particularly, but exchanging that 1030 for another (larger) size may be the answer to my problem.

So, the questions: (1) Any ideas what's going on? (2) Is there another solution, other than going to an oversize belt? (3) If so, how much larger do I go on the belt size? 25.4mm to an inch, so try a 1045 or 1050?

Frustrated in Carolina!
johnbonds

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  #2  
Old 09-12-2008, 07:39 PM
toomany MBZ's Avatar
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Join Date: Nov 2006
Location: central Va
Posts: 7,820
I had a similar problem on my SD, belts too short.
I believe that may be your case.
Do you have two alt belts?
I also had to replace the bracket you did. Yet that problem was too long of belts, and to tighten, I broke the bracket.
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  #3  
Old 09-12-2008, 07:52 PM
johnbonds
 
Join Date: Sep 2008
Location: Mount Pleasant SC
Posts: 56
Alternator replacement

The 240D has a single belt (13x1030 is specified). I've just gone to the parts store and have a 1040 and a 1050 belt in hand. But I'm going to wait overnight and see if someone has had the problem before and found a better answer than taking all those belts off to change the inner one.

Thanks for the response!

jb
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Old 09-12-2008, 09:48 PM
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Join Date: Sep 2005
Location: West Michigan
Posts: 2,076
have you tried installing the adjust ement bracket on the alt first b4 installing the alt to the car? I found that is the best way to get that bracket in place correctly.
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  #5  
Old 09-12-2008, 11:06 PM
johnbonds
 
Join Date: Sep 2008
Location: Mount Pleasant SC
Posts: 56
Alternator replacement

Yes, I did install the bracket before the alternator this last time--but you can't put the adjusting bolt in the bracket until the alternator ear is there to be "grabbed by the bolt (the one with the adjusting screw extension on it). The bracket is attached to the aluminum support casting secured to the engine, and the bracket HAS to be installed on that with the uppermost bolt, adjacent to the block, before the support casting is put on the engine, at least on my engine. There is not enough space behind the bracket to take out or insert that bolt from the rear forward.

So the alternator is installed on the lower pivot bolt now, and with the belt on, is pulled very tightly under the bracket, pushing it into the cooling water fitting (and hose) which runs over it. There is no slack in the belt to speak of, and I can't get that adjusting bolt (with the long thin extension) to mate up with the hole in the upper "ear" of the alternator, because of the alternator's position very close to the engine block.

Thanks for commenting!

jb

Here's two photos, one from the side. In the side view, note that the alternator is pulled right up into the bracket by the belt, and the bracket is pushed up into the cooling water line. In the top view, look at the distance from the side of the engine bay to the alternator. Generally the alternator is within an inch of that edge.
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Alternator replacement.  1982 240D-dsc00251.jpg   Alternator replacement.  1982 240D-dsc00253.jpg  
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  #6  
Old 09-13-2008, 08:20 PM
johnbonds
 
Join Date: Sep 2008
Location: Mount Pleasant SC
Posts: 56
Alternator Replacement SITREP

OK, I bought the bigger belt (got a 1040 and a 1050mm belt). Started the removal of the other belts in the way. Power steering pump yielded as expected and belt removed. A/C unit will not move enough to get the belt off.

All three 19mm bolts are loose, nearly finger loose, and 1/8" slack between bolt head and seating surface. The adjustment screw is quite loose, with the nut sticking up 1" or so. I presume this compressor rotates on the upper pivot bolt clockwise looking aft (since lengthening the adjustment is suggested for loosening...). But it doesn't want to do this, or move toward the engine either. I've tried prybars and the like to no avail.

Four hours invested in that A/C belt so far. Obviously, I'm missing something.

Help?

johnbonds
'82 240D 4sp
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  #7  
Old 09-14-2008, 08:14 PM
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Quote:
Originally Posted by johnbonds View Post
OK, I bought the bigger belt (got a 1040 and a 1050mm belt). Started the removal of the other belts in the way. Power steering pump yielded as expected and belt removed. A/C unit will not move enough to get the belt off.

All three 19mm bolts are loose, nearly finger loose, and 1/8" slack between bolt head and seating surface. The adjustment screw is quite loose, with the nut sticking up 1" or so. I presume this compressor rotates on the upper pivot bolt clockwise looking aft (since lengthening the adjustment is suggested for loosening...). But it doesn't want to do this, or move toward the engine either. I've tried prybars and the like to no avail.

Four hours invested in that A/C belt so far. Obviously, I'm missing something.

Help?

johnbonds
'82 240D 4sp
When I did mine (300D), I slightly loosened the 3 19mm ac compressor bolts and also removed the small bolt that holds down the 2 oil cooler lines onto the top part of the compressor. If you have this, this keeps the compressor from moving much. see pic.
Attached Thumbnails
Alternator replacement.  1982 240D-300d-ac-comp-bolt.jpg  
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the sooner you start... the sooner you'll get done If it ain't broke, don't fix it.. Its always simpler to tell the truth...
2007 Honda Accord EX
2007 Honda Accord SE V6
96 C220
97 Explorer - Found Another Home
2000 Honda Accord V6 - Found Another Home
85 300D - Found Another Home
84 300D - Found Another Home
80 300TD - Found Another Home
Previous cars:
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87 Camry
84 Cressida
82 Vanagon
80 Fiesta
78 Nova
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Opel Kadet
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Contessa
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  #8  
Old 09-14-2008, 11:42 PM
johnbonds
 
Join Date: Sep 2008
Location: Mount Pleasant SC
Posts: 56
Alternator replacement SITREP

Yes! Freeing up those hoses did the trick, and the A/C belt came off. I cut off the too-short alternator belt to save time. The alternator is now installed with a 13 x 1050 belt, which fits nicely. The alternator is in the middle of the travel with the belt tightened for use. I cut off the excess adjustment screw thread so it would fit into the bezel nut with the alternator at full travel toward the block and it's now engaged and tensioned.

I now have all the belts back on, and have quit for the night. I'll tighten the AC and PS pumps tomorrow morning.

Thanks for all the help from you guys! I really appreciate it.

John Bonds
'82 240D 4sp, 200k (30mpg, town and highway)
'99 Lexus LS400, 85k (21mpg town, 27mpg highway--80mph).

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