need parts FAST !!!!! belt tensioner
 

I threw the main belt and need the tension arm, and the shock I was told..
the price i thought was a little bit high anyone know where to get it for a good price?

Right at the top of this page - from FastLane or PartsShop, best dang prices PLUS Airborne Overnight delivery for a nominal fee.

what is it located under....the name of the parts???? I'm not sure if I'm calling it right because what I looked at was about $200 cheaper than the mechanic told me it would be...

Using FastLane's online catalogue, searching your year and model I found the tensioner at the foloowing link.

http://catalog.eautopartscatalog.com/mercedesshop/wizard.jsp?partner=mercedesshop&year=1987&make=MB&model=300-E-002&category=G&part=Accessory+Belt+Tensioner

This and all the tensioner items can be found under the cooling system link, many have pictures to help ID the part in question.

I always hear about these tensioners going bad but never understood which part of it did. What can go wrong with this tensioner besides the threading rod that adjusts it up and down? (stripped)

I suppose the pulley could go bad but other than that there are no other moving parts on the tensioner itself that can wear out?!

~Paul

___________________
'91 300E, 215K miles

well I shredded the belt and the arm was stripped so it wouldn't tighten.....thanks for the help...

The shock bushing can wear out. The associated play afterwards makes a terrific amount of noise at idle...sounds like a rod going south!

Ill tell ya what goes wrong. Its the fact that MB uses rubber as the elastic element in the tensioner. There is rubber in between two circular pieces of metal which is normally under tension (twisting). After a lot of time and heat the rubber looses its strength and takes on a new "set". And then its junk.

You won't have this problem anymore as soon as you modify it by adding ga.14 x 3" long tension spring hook towards a piece of plate 3/16 x 1 x 4 with 2 holes bolted on the power steering resevoir, just change the two bolts to make them a bit longer. The whole thing serves as a counter tensioner which help the molded rubber thing. I got tired of replacing the whole tensioner unit (3 times at $200.00 each) so i made changes and after 8 years it doesn't bother me anymore. Apparently, its a lousy MB design.... imagine a molded rubber on an aluminum casing that serves an enormous torque? that small shock absorber doesn"t help much either.... Good luck...

A simple O ring inserted between the bushing and the washer, no more rattle. Good as new.

The whole rubber molded on the casing serves as torque belt tensioner and one's the rubber begins to deteriorate, which is squeeze between the shaft and casing (bolt), then you can hear this clinging/banging noise specially when it's on idle. Then there's the problem... solution....... replace the whole tensioner unit again & again & again.... they don't last.. until you modify it. Inserting an O-ring in between the unit and the holder bolted together might help eliminate noise temporarily but one's the o-ring is pressed and squeeze between metal to metal then there's the problem again... From a city driving experience (stop and go)they only last 25000 to 30000 miles!!!!!! that's bad/lousy engineering design.

Pineda
I don't have the problem yet, but each time I do anything with the belt I keep my fingers crossed that there wont be a problem with the tensioner. I'm interested in your modification, could you post some pictures or a sketch of how you did it?
Thanks
Ernie

Yes please post a picture and directions of this modification.. This d*mn tensioner, adjuster and belt problem is going to cost me an extra $100:mad: for a hood hinge. Please don't ask why (look under the post "I don't believe this *****) just post the modification:D :D .

thanks guys for all the info......it just cost me $450....

please post about the bracket you made........

speedylizard,

I know that this is alittle late in the response but, What came out to $450.. The tensioner and the shock(damper)? If so where did you purchase these items from? Did that include labor, lunch and drinks???

Well the parts and labor.....what I thought was a trusty mechanic has turned out to be my nightmare and I think I'm going to be looking for a new mechanic. this isn't the first time I've felt robbed about the price I'm paying and he's suppose to be giving a "friend's" hook up but I think his shop is hurting right now and he's not giving much leway.......

Too Much Tension might cause early failure.
 

I have only one cars worth of experience (87 300E) but in recently installing a new water pump I had to study this tensioner to see if it also needed replacement. What I decided is that if you re-use a tensioner you should not over tighten it or it may fail very quickly. The problem comes when you set the little pointer back at the loose end of the scale (just like the book instructs). This was good advice IF the tensioner was new, BUT if you are re-installing a used one I THINK you should only set the pointer to the distance it retracted to when you loosened it while removing it. Did you notice that it did not come back to the loose end of the scale? It had taken a "set" from use and heat. So if you start THERE and tighten it to the required end mark (tight) you should be approx. where it was running before. If you place the whole thing under too much tension you invite bearing failures on alt. and idler pulleys and tensioner unit, and the belt itself. ??? Am I thinking correctly? This is the way I set mine up and it seems to be doing great with a new belt and water pump.

Good luck to you,

DanielW

If you do as DanielW suggests you will not have the correct amount of tension on the belt. The rubber takes a "set" and looses some of its tension.

I'll will let everyone know with a post if belt slips later.
 

I thought about it that way too, but decide to try the method I described because of reading so many posts about tensioner failures and-or short life. Right now there is NO sign that the new belt is slipping any at all. The old belt was not slipping, I just replaced it as a maintence-time issue. It did have some inner circle cracking on the small "V's" . It might have worked for years with these small cracks but I was in there so it made sense to renew the belt.

The apparent belt tension is about what it was before replacement, but I have no way to really accurately measure it. I just didn't want to risk tearing the tensioner apart since I am sure the rubber in it is harder and less compliant than when new. I did replace the upper bushing on the shock with a spare bushing which happened to have the exact size. Had come off of an old BMW air pump mounting which I had saved in the toolbox, WHY ? go figure.? It was still relative soft and fit real tight. The only reasing I am talking about that bushing is I suspect that shock slack is a major factor in the demise of the tensioners since that movement can stress the tensioner. If you can feel any movement much (at the top of the shock mounting) while idling you probably will be buying a tensioner soon !!

I'll be sure to post if my ideas about this prove out wrong ---

Luck with yours,
DanielW

How many hours labor is it to replace a belt tensioner and damper?

How many hours would a shop charge?

I did the labour my self (no special tools required, almost!)
 

3.0 hours or more at most shops... I checked with 2 One said a flat rate of $175.00 plus tax 7% + any thing extra they might run into. The other said 3.0 hours at $70.00=$210.00 plus the parts.
They did not wish to do the work with my parts(Belt, WP and Thermostat) which I had alread aquired here from PARTS for $191.00. So after considering these two shops I decided to do it myself. The only special tools required are: (1) a small round file to hold the fan clutch pully. An out of sight hole is in the pulley which the file fits into and holds against the notches on the housing. I bent the file handle 90 degrees at 1 inch from the end on the handle. Other people say a strong wire of about 1/8 inch works to hold it. and (2) a 13mm flex socket (6 point is prefered) used with several extentions, (3) you may need some allen sockets in size 6mm, 8mm. (4) I think I used a 10" and two 3" extensions. The parts have to come off in order. fan shroud, fan blades, fan clutch, belt loosen, then tensioner bracket then tensioner itself, Power steering pump- lay over to the right but don't take off hoses. Then try the bolts on water pump---Depending on your tool and extentions you may also have to drop the AC compressor down onto the suspension--but don't un-do ANY hoses here.

This was the first time I had done this particular job so I took most of two days to do the work. But I'm not as young any more. It is a DIY job but I did scratch myself up some. It a hard job, the back two water pump bolts are really hidden under a lot of stuff.

Luck to you, SEARCH these archives and print out the steps. I had to do that because I don't have a CD or manual yet.

DanielW

hmmm... I think I'll pay for someone else to take that a$$ whooping for me. I had originally posted the question of how long etc, because someone made a comment that $450 bucks was too much to pay for the installation. I've talked to my MB mechanic and he quoted me about $430 but that included the belt and would be the price out the door. Sounds like he is reasonable.


Thanks for the feedback.

Could you post a picture with details of the modification.
Thanks
Harrison

Could you post a picture with details of the modification.
Thanks
Harrison