Results 1 to 23 of 23

Thread: Serpentine Belt Tensioner (early / manual style)

  1. #1
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Serpentine Belt Tensioner (early / manual style)

    So, my new lower harness is in, but I still barely made it home from the mechanic from hell's shop (last time there ever!)

    Before I isolated the harness issue, he said the alternator was bad (it's good) but I have a rebuilt one (that he could swap for a minimal fee).
    Turns out, as I did my lower harness, he did not swap the alternator. But oh, he did have an assistant 'tighten the belt'.

    Well as it turns out, seems like tightening the belt must be done very carefully on the 1992 500e? From what I gather, there is an order to follow before any adjustment can be made?
    My belt is literally hanging off, about 2-4 inches of slack, I'm not sure how I made it home - I was close to stalling out at red lights and squealing everywhere.

    The nut (with the plastic arrow indicator) loosens but nothing happens when it is tightened. The plastic arrow indicator was 180 degrees from the marker section.
    The top screw-thing, with the rod beneath it, does nothing but shift from left to right when adjusted.

    Is there a how-to on this and potential replacement that I am missing? Or did the mechanic not break it and I'm just doing something wrong?
    It was fine before, no belt problems. The first picture is after I moved the plastic indicator back up. (Is the arrow even facing the right way?).
    *Edit* It's not is it?? ArRRggh.

    IMG_2140.jpg IMG_2146.jpg IMG_2143.jpg
    Last edited by ALL500; 05-06-2016 at 01:41 PM.

  2. The Following User Says Thank You to ALL500 For This Useful Post:

    Eno (05-06-2016)

  3. #2
    E500E Guru TerryA's Avatar
    Join Date
    Jul 2009
    Location
    Orange County, CA
    Age
    74
    Posts
    852

    Re: Serpentine Belt Tensioner

    Another reason to do your own work if possible. I think some mechanics create more work for themselves.
    Terry

  4. The Following User Says Thank You to TerryA For This Useful Post:

    ALL500 (05-06-2016)

  5. #3
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Re: Serpentine Belt Tensioner

    At least he let me swap my lower harness in his muddy, wet, chemically yard...

  6. #4
    postwhore posterchild Klink's Avatar
    Join Date
    Feb 2014
    Location
    Abstract Plains, USA
    Posts
    3,570

    Re: Serpentine Belt Tensioner

    Quote Originally Posted by TerryA View Post
    Another reason to do your own work if possible. I think some mechanics create more work for themselves.
    I've been around mechanics, service advisors, and shop owners my entire working life. Believe me, you are actually giving us way too much credit by imagining that...
    Putting the fun in dysfunction...

  7. The Following 2 Users Say Thank You to Klink For This Useful Post:

    sheward (05-06-2016), TerryA (05-06-2016)

  8. #5
    Site Honcho
    Klugscheisser
    Ich bekenne mich
    nicht schuldig.
    gerryvz's Avatar
    Join Date
    Nov 2008
    Location
    The Woodlands, Texas, USA
    Posts
    14,741

    Re: Serpentine Belt Tensioner

    There is a HOW-TO on replacing the serpentine belt, but it is primarily for the later (1993-1994) cars with the automatic belt tensioners, that make the job much easier. 1992 & early 1993 cars are a bit more involved with the process. I'm attaching the factory procedure on serp belt replacement and adjustment for the early cars.

    http://www.500eboard.com/forums/showthread.php?t=7375

    Cheers,
    Gerry
    Attached Files Attached Files

  9. The Following User Says Thank You to gerryvz For This Useful Post:

    sheward (05-06-2016)

  10. #6
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Re: Serpentine Belt Tensioner

    Thanks a lot Gerry. So it's safe to say that with no belt-tightening happening when the bolt and rod are adjusted, that I need a new tensioner?

  11. #7
    Site Honcho
    Klugscheisser
    Ich bekenne mich
    nicht schuldig.
    gerryvz's Avatar
    Join Date
    Nov 2008
    Location
    The Woodlands, Texas, USA
    Posts
    14,741

    Re: Serpentine Belt Tensioner

    I've never had a car with the early-style tensioner, so I'm not up on how they work. GSXR or Klink can likely fill you in on what is needed. However these tensioners can/do go bad and need replacement.

  12. The Following User Says Thank You to gerryvz For This Useful Post:

    ALL500 (05-06-2016)

  13. #8
    E500E Guru
    Join Date
    Feb 2011
    Location
    DFW Texas
    Posts
    2,258

    Re: Serpentine Belt Tensioner

    I believe it works like the M103 tensioner. You are applying tension to an arm which preloads rubber. The rubber is in torsion, which by MIL-rubber handbook is a big-no-no. If he's got slack, it maybe a bad tensioner. I think MB's idea was the rubber would act as a spring and dampener.


    Make sure the pointer is seated... boy I don't like those. I know some of those later-early cars had a front timing cover which would take the later style tensioner.


    M

  14. #9
    Senior Member Eno's Avatar
    Join Date
    Oct 2015
    Location
    Doha, Qatar
    Posts
    149

    Re: Serpentine Belt Tensioner

    I am in the process of ordering/changing this above described part for my 1992 500E with part #: A119 200 02 70.
    It is cracked/broken in the frame. I am gonna decide between the MB OE part or a Canadian brand. Thank you guys for sharing your exeperience and knowledge.

    Kind regards,

    Eno

  15. The Following User Says Thank You to Eno For This Useful Post:

    ALL500 (05-06-2016)

  16. #10
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Re: Serpentine Belt Tensioner

    Not sure how to check if anything is cracked or broken, until I take it apart, can't see much there. Eno, what is the Canadian brand you are looking at? From all accounts this is a part to go to the dealer for?
    Is there a way to diagnose for sure weather the part is actually broken, without taking it apart?

  17. The Following User Says Thank You to ALL500 For This Useful Post:

    Eno (05-07-2016)

  18. #11
    .036 Hoonigan™
    E500E Boffin
    gsxr's Avatar
    Join Date
    Dec 2008
    Location
    Boise, ID, USA
    Posts
    17,755

    Re: Serpentine Belt Tensioner

    1) You MUST loosen the large pivot bolt before adjusting belt tension, then you must re-tighten it afterwards.

    2) There is no way to tell if the tensioner is bad without removing it and checking on the bench in a vise (per FSM procedure), unless it's REALLY hosed in which case you may be able to tell by loosening / partially removing it... but at that point, just take it off.

    3) Be careful buying replacement tensioners, last time I checked the aftermarket no longer carried OEM, only junk stuff that I wouldn't trust. If you can't find a name brand, buy OE. From a quick look (p/n 119-200-02-70, $334 dealer list, ~$250 discount) the only aftermarket brands currently available are Uro (junk) and Febi (crapshoot). The Febi is ~$100, if you gamble on it, please post photos so we can compare to the OE/OEM unit.

    4) The order of assembly is critical, make sure the washer/adjuster on the back side is not reversed. And DO NOT over-tighten! It's better to under-tighten, which is easily cured, than to over-tighten and possibly destroy a new $250+ OE tensioner.


    All of the above is why I really, really like the late-style automatic spring-loaded tensioners. From your photos it appears your car is a late 1992 model with the appropriate mounting boss cast into the timing cover, so it's possible to convert, but it's a pretty complicated upgrade. Another forum member documented the process in a thread with pictures, it requires some part swapping plus drilling / tapping the timing cover boss. If the car is a long-term keeper I'd consider this, otherwise just replace the blasted rubber thingy.

    Dave M.
    1997 E420 (Bugeyes)
    1994 E420 (Blondie)
    1994 E500 (Q-ship)
    1992 500E (Mach 5)
    1987 300D (Sportline Stage 2)
    Click here for my website
    Click here for my YouTube channel

  19. The Following 5 Users Say Thank You to gsxr For This Useful Post:

    ALL500 (05-06-2016), Eno (05-07-2016), gerryvz (05-07-2016), sheward (05-06-2016), TerryA (05-07-2016)

  20. #12
    Senior Member mercepor's Avatar
    Join Date
    Jan 2012
    Location
    Hungary, France
    Posts
    173

    Re: Serpentine Belt Tensioner

    I had the same prb with my tensioner, yours is also broken, the rubber is cracked, we can see it on your picture.
    If you overtighten these old tensioners, you can crack them easily.
    On your photo the rubber seems to get out from the frame, it is like an "omelette"....
    You should change it and just follow the factory procedure when tightening.
    Probably your mechanic broke it.
    Last edited by mercepor; 05-07-2016 at 04:27 PM.

  21. The Following 4 Users Say Thank You to mercepor For This Useful Post:

    ALL500 (05-06-2016), Eno (05-07-2016), gerryvz (05-07-2016), TerryA (05-07-2016)

  22. #13
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Re: Serpentine Belt Tensioner

    Thanks Dave,

    1) The large pivot bolt is the top one attached to the rod? If so, I loosen until it can freely move left/right?

    2) Ok.

    3) I definitely don't want any URO junk in my car, the Febi is not inspiring.

    4) Check)

    5) I think I'll stick with a carefully installed, unmodified set up.
    Last edited by ALL500; 05-06-2016 at 09:11 PM.

  23. The Following User Says Thank You to ALL500 For This Useful Post:

    TerryA (05-07-2016)

  24. #14
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Re: Serpentine Belt Tensioner

    Ok, thanks mercepor - I'm understanding what I'm looking at a little better. Yes, this is the last in a long line of fudges from the 'mechanic'. He once told me (when I first had harness issues) that I should swap the motor with one of his junked 300e's. (drumroll/cymbals). True story.

  25. The Following User Says Thank You to ALL500 For This Useful Post:

    TerryA (05-07-2016)

  26. #15
    .036 Hoonigan™
    E500E Boffin
    gsxr's Avatar
    Join Date
    Dec 2008
    Location
    Boise, ID, USA
    Posts
    17,755

    Re: Serpentine Belt Tensioner

    Quote Originally Posted by ALL500 View Post
    Thanks Dave,

    1) The large pivot bolt is the top one attached to the rod? If so, I loosen until it can freely move left/right?
    No. The pivot bolt goes through the middle of the tensioner, it's big, either 17mm or 19mm hex head. This needs to be loosened (say, 1/2 to 1 turn) and then you adjust tension via the rod, which has a 13mm (?) hex head and possibly left-hand thread. It's been a few years since I fiddled with one of these and I can't remember details offhand.

    Have you tried searching the forum? I thought there was a thread or two on this manual tensioner but it may have been 3-5 years ago...


  27. The Following User Says Thank You to gsxr For This Useful Post:

    TerryA (05-07-2016)

  28. #16
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Re: Serpentine Belt Tensioner

    Great! Typing in 'manual tensioner' got me the info I need. Indeed, what an interesting design they have here...

    Spring-tensioner upgrade? Hmmm...

  29. The Following User Says Thank You to ALL500 For This Useful Post:

    TerryA (05-07-2016)

  30. #17
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Re: Serpentine Belt Tensioner

    I found this video of the tensioner replacement on an R129. I'll try to document the process as best I can with pictures when I get to it.

    https://www.youtube.com/watch?v=_3juL9PixuU


  31. The Following User Says Thank You to ALL500 For This Useful Post:

    TerryA (05-07-2016)

  32. #18
    Senior Member Eno's Avatar
    Join Date
    Oct 2015
    Location
    Doha, Qatar
    Posts
    149

    Re: Serpentine Belt Tensioner

    I was told by a friend of mine about the belt tightener/tensioner with the name brand 'Litens', a Canadian product, which he said are as good as INA. I agree this is a delicate and expensive part. GSXR is right, 250USD is the OEM MB Ina.
    A technical inspection of the serpentine belt tightener by an authorised MB service told me that I have a broken belt tensioner. When I remove it I'll see in condition it is.

  33. The Following User Says Thank You to Eno For This Useful Post:

    ALL500 (05-07-2016)

  34. #19
    .036 Hoonigan™
    E500E Boffin
    gsxr's Avatar
    Join Date
    Dec 2008
    Location
    Boise, ID, USA
    Posts
    17,755

    Re: Serpentine Belt Tensioner

    Had time to do a quick search, here are some relevant threads:

    http://www.500eboard.com/forums/showthread.php?t=4475

    http://www.500eboard.com/forums/showthread.php?t=8064



    Late-style auto-tensioner retrofit info:

    http://www.500eboard.com/forums/showthread.php?t=5677


  35. The Following 3 Users Say Thank You to gsxr For This Useful Post:

    ALL500 (05-07-2016), Eno (05-07-2016), gerryvz (05-07-2016)

  36. #20
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Re: Serpentine Belt Tensioner (early / manual style)

    So I bought the tensioner from Universal German Auto Parts Inc. (eBay store, $140 USD + shipping ) in Sun Valley CA:
    http://stores.ebay.com/Universal-German-Auto-Parts-Inc


    I asked them first if it was manufactured in China and they were highly offended. Made in Japan and supposedly top quality.
    So far so good. Time will tell.

    When doing the job, be sure to screw the top nut adjuster all the way down before re-installing.
    I made sure the big bolt was loosened before adjusting the tension, then tightened after.

    I should probably have worn gloves.


    IMG_2229.jpg IMG_2230.jpg IMG_2231.jpg IMG_2232.jpg IMG_2233.jpg

  37. The Following 3 Users Say Thank You to ALL500 For This Useful Post:

    500AMM (01-17-2017), gsxr (06-27-2016), sheward (06-27-2016)

  38. #21
    .036 Hoonigan™
    E500E Boffin
    gsxr's Avatar
    Join Date
    Dec 2008
    Location
    Boise, ID, USA
    Posts
    17,755

    Re: Serpentine Belt Tensioner (early / manual style)

    I've never heard of any M119 tensioner made in Japan. Was there are brand name on the box or bag it came in?

    Very odd they list no brand name in their listing:
    http://www.ebay.com/itm/w140-w124-w1...-/160509056239


  39. #22
    Senior Member ALL500's Avatar
    Join Date
    Feb 2014
    Posts
    275

    Re: Serpentine Belt Tensioner (early / manual style)

    Maybe they're taking me for a ride? I dunno. No brand name on the box/package or the tensioner either.

    Screen shot 2016-06-28 at 1.55.13 PM.png

  40. The Following User Says Thank You to ALL500 For This Useful Post:

    gsxr (06-28-2016)

  41. #23
    Junior Member
    Join Date
    Oct 2010
    Location
    Titusville FL
    Posts
    20

    Re: Serpentine Belt Tensioner (early / manual style)

    I want to share my recent early tensioner replacement. I purchased a Lasso brand tensioner off of Amazon for $130 and a Mercedes 8 rib belt. When tensioning the new tensioner, I came to the realization that I was missing the pointer. I found the part number and cost (approx $25) but did not want to order and wait. Therefore, I used nail polish to mark the snug but at rest location and then watched it move as the tensioner was tightened. Here are a couple pictures. The camera angle is not directly aligned with the marks, though. I will likely look get a pointer at some time in the future and install it when messing with something else on the engine.
    Lee
    Attached Images Attached Images
    Lee Zook

    92 500E
    87 300D
    86 Porsche 944 Turbo

  42. The Following 4 Users Say Thank You to zooklm For This Useful Post:

    500AMM (01-17-2017), ALL500 (01-17-2017), emerydc8 (01-14-2017), gsxr (01-14-2017)

Similar Threads

  1. New style belt tensioner retrofit
    By myarmar in forum M119 Engine
    Replies: 26
    Last Post: 02-09-2016, 10:12 AM
  2. HOW-TO: Replacing M119 Serpentine Belt (with automatic tensioner)
    By gerryvz in forum "HOW-TO" Tutorial Articles
    Replies: 15
    Last Post: 07-20-2015, 01:55 AM
  3. Serpentine belt tensioner - help!
    By e500.org in forum M119 Engine
    Replies: 7
    Last Post: 06-21-2015, 08:52 AM
  4. Replies: 5
    Last Post: 08-03-2013, 08:35 AM
  5. Manual Belt Tensioner Brand?
    By Hollybrook in forum M119 Engine
    Replies: 16
    Last Post: 11-11-2012, 11:01 AM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •