Rookie question - alt belts... - Page 2 - PeachParts Mercedes-Benz Forum

#16 06-14-2006, 09:57 PM

Quote:

Originally Posted by techguy512

Yes I tried heating, no go. I have nice access to the threaded end, since my radiator and condensor are out of the car. I'm tempted to just drill it out.....

I guess that would work, there seems to be enough room to use a longer bolt and a nut. I would try using excessive force first (like a hammer and a long wrench), if it breaks, then you can drill it anyway. Someone must have really over-tightened it.

P.E.Haiges · #17 06-15-2006, 12:05 PM

Merc,

If the ALT belts don't come off with the ALT moved all the way toward the engine, the wrong belts are installed on the engine.

Cut off the old belts and get the correct new belts. There should be plenty of clearance over the pulleys to install the correct belts when the ALT is in the loosest position.

P E H

MercFan · #18 06-15-2006, 12:11 PM

Quote:

Originally Posted by P.E.Haiges

Merc,

If the ALT belts don't come off with the ALT moved all the way toward the engine, the wrong belts are installed on the engine.

Cut off the old belts and get the correct new belts. There should be plenty of clearance over the pulleys to install the correct belts when the ALT is in the loosest position.

P E H

Good tip - will do... thx

P.E.Haiges · #19 06-15-2006, 12:33 PM

techguy,

The problem is caused by solid state diffusion in dissimilar metals: steel bolt, aluminum ALT mount.

Try heat again from an actylene torch that concentrates the heat in a small area. A small propane torch won't work. Be careful not to melt the aluminum.

Here is an example how heat is used to remove stuck screws. I have never seen a case where heat would not work getting bolts or screws unstuck.

I could not get the 2 screws out that attach the V-regulator to the ALT. I knew if I turned them too hard, they would break off.

So I carefully heated the ALT case as near to the screws as possible with a low flame from my acetylene torch. I used a steel shield to protect the V-regulator from the heat. I carefully worked the screws back and forth after heating the ALT and they eventually came out. Before I put the screws back in, I ran them thru a thread die and tapped the hole. I applied Neversieze to the holes and screws before I reinstalled the V-reg.

I did the above work with the ALT removed from the car because I had to put this ALT in another car. But I probably could have done it with the ALT in the car.

P E H

techguy512 · #20 06-15-2006, 01:29 PM

Quote:

Originally Posted by P.E.Haiges

Try heat again from an actylene torch

Can I try MAPP gas instead? I don't want to hassle with
actylene.

Thanks.......................

P.E.Haiges · #21 06-15-2006, 07:01 PM

techguy,

U can try MAPP gas. What U want is a pencil point flame that concentrates the heat in the area where the bolt is screwed in.

Since the temperature coefficient of expansion of aluminum is 3 times that of steel, the aluminum will expand away from the steel bolt and break the bond.

Work the bolt back and forth with a wrench while it is hot.Then the bolt should screw out. Tap the thread before putting the bolt back in and use Neversieze compound.

P E H

dmorrison · #22 06-15-2006, 07:38 PM

Let make sure your loosenig all the correct bolts.

Look at the parts diagram below.

One note first. bolt #89 and 86D are now a one piece welded bolt.

At the rear of the alternator you are going to loosen 3 bolts/nuts.

The bolt head of #81E. which goes into a mounted nut on the upper braket #78 ( this is a pivot bolt for the upper bracket, which must pivot while loosening )
The nut at the rear of bolt number 73D ( this is the pivot bolt for the alternator)
The nut to bolt 86D, not shown (this is a clamping bolt on the upper part of the alternator)

Once all three bolts/nuts are loose you rotate nut # 79 to loosen the alternator belt by moving the alternator towards the center of the car. Once move enough the belt can be removed.

I recommend Mercedes belts. I got Gates belts for my daughters car and have had problems with all three.

Now if your bolts are rusted PB blaster is the best. If not all 3 are loose, then it will not budge.

Dave

tangofox007 · #23 06-15-2006, 07:48 PM

I think that bolt 73D is shown backwards in the diagram. It goes through the mounting bracket from rear to front and has no nut. It threads into the alternator front casting.

techguy512 · #24 06-15-2006, 11:10 PM

Quote:

Originally Posted by tangofox007

I think that bolt 73D is shown backwards in the diagram.

My car agrees with Tangofox. The head of 73D and the compression washer 75 are on the back. This is the bolt that
won't budge.

#25 06-15-2006, 11:14 PM

Quote:

Originally Posted by tangofox007

I think that bolt 73D is shown backwards in the diagram. It goes through the mounting bracket from rear to front and has no nut. It threads into the alternator front casting.

I agree also, the bolt goes from rear to front with no nut on my 82 300D.

dmorrison · #26 06-16-2006, 12:21 AM

Haven't looked at mine. But this is the Mercedes parts catalog book I have. If its just a regular straight bolt it may go on towards the rear or towards the front.
they may have modified the instalation of the bolt just as they modified the 68D and 89 bolt.
Dave

(Edit) Just looked at mine and mine is also on with the head at the rear.

vstech · #27 06-16-2006, 12:57 AM

Quote:

Originally Posted by techguy512

I'm having a hell of a time getting the alt to pivot in order to get the belts on.

Looking at the rear of the alternator, it appears that there's an
adjusting bolt at the 11 o'clock position, and a pivot bolt at the 5 o'clock
position. I cannot, no matter what I do, get the pivot bolt loosened
enough to allow the alternator to move.

I've tried heat, I've tried PB Blaster, I've put enough torque on the bolt to lift
the engine, and nothing will move it. Do I need to drill it out, or am I missing
something obvious.

Thanks,
Bob
'82 300D

rust in not a problem on any of the bolts on my engine

but a good 6 point 17MM socket and a hinge handle should transferr enough shock with a good hammer blow to get it loose. the lower bolt should be easilly whacked. you may have to get it from below, but youshould be able to get it.
if you have no hinge handle a QUALITY box wrench and a hammer should shock it too.
John

dmorrison · #28 06-16-2006, 01:02 AM

Quote:

Originally Posted by techguy512

Yes I tried heating, no go. I have nice access to the threaded end, since my radiator and condensor are out of the car. I'm tempted to just drill it out.....

Either an impact wrench, drill it out or grind off the nut on the bolt.

Dave

dmorrison · #29 06-16-2006, 01:15 AM

For MercFan

Removing the Ac compressor belt.

Loosen the 3 bolts on the back of the compressor. Photo #1. IF you completely remove the bolts, keep track of which washer/separator goes where.
Now adjust the tension using the adjusting nut as show in the picture. Photo #2.

Removing the power steering pump belt.

Loosing the 3 bolts in the rear of the pump. See Photo #3 and #4. I did not get down far enough to get the bottom inboard bolt head.
BE CAREFUL NOT TO PINCH OR CUT THE CLEAR PLASTIC DIESEL FUEL LINE NEAR THE ONE BOLT
Adjust the tension with the adjusting bolt. Photo #5

Dave

MercFan · #30 06-16-2006, 02:40 PM

Quote:

Originally Posted by dmorrison

For MercFan... Removing the Ac compressor belt...

Thanks - this helps a LOT - I'm a visual type...