I went out just now and looked at the pulley on my car and it sits out from the alternator housing about 1/16". It looks like when the over run assembly in your pulley failed, it ground into the alternator housing.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Ok guys, this is not a happy happy update. The knock is still there.

I have changed the alt pulley, took the alt off and it tested fine at autozoo, without any knocking, replaced the tension lever(incl. new washer and seal), new tension lever shock and the damned knock is still there. Now, it is not as constant as before, but when it does happen the tension lever definitely rocks. Not sure if that is helpful.

As far as I can tell the belt tensioner, WP pulley, PS and Ac pulleys are all fine, spin easily and without any play.

This is confusing because without the belt on there is no knock. So what could the belt be tightening, offsetting or otherwise pulling out of true to make this knock. I'm beginning to think this is in fact internal to the engine, but really hope not.

I think I have changed all the external components that make sense, so any ideas or thoughts are appreciated.

Here is the old vid with belt on and Knock
https://www.youtube.com/watch?v=L-7J6ur3Y7M

Here is a new vid with belt off and NO knock
https://www.youtube.com/watch?v=6IhTGGXuYpw

__________________
Treetops
06 E320 CDI 127K Miles
87 300TD 231K Miles

99 E300 269K Miles-Sold

Get yourself a mechanics stethoscope, remove the fan and stick it on every part of belt drive you can reach.

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CENSORED due to not family friendly words

Thanks for the suggestion on the stethoscope I got one and yep its the alternator. I may have not noticed it before but now there's certainly a wobble to the pully. I'm sure these are easy to rebuild but given my job and time constraints I'm just going to get a new one.

Not the 'pressure relief valve ' in the power steering pump clanking is it ?

https://m.youtube.com/watch?v=a9yIY-Sw_Jk

If the new alternator comes with a pulley, make sure it is the over run type not a solid one.

If it turns out that the new one has the proper pulley, I'd be willing to take the other new pulley off you hands because I think mine may be going south as well.

__________________
-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Got the new alt in and that damned knock is gone, whew. I am guessing when the pulley went, when I really goosed it, it tightened itself down all the way to the housing. I am thinking this broke the windings loose which just got worse in the relatively short amount of time I drove it.

While it took a long time, ten days, to get to this point I do thank those who chimed in an helped. Hopefully, this will be helpful to someone else in the future.

Evan, sorry but I tried to get the new pulley off as did the shop I bought the new one at. It wouldnt budge so Im thinking it also over-tightened itself like the 1st one. a shame really.

Well back on the road now so alls good.

__________________
Treetops
06 E320 CDI 127K Miles
87 300TD 231K Miles

99 E300 269K Miles-Sold