Help, lost a belt and pulley looks knackered!!

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GordyB

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On motorway last night and battery charge warning came on the dash, noticed as changing lanes that the steering had gotten heavier and then after another 20 minutes of "I can make it home before it dies" about every warning light came on and I lost power. Taken home on a low loaded as the belt that drives the alternator and the PAS pump had shredded. In daylight this morning I can see a pulley that looks knackered which would explain why the belt wasn't happy. Photo below.

It's a 1999 CLK W208 320 petrol.

Can someone tell me if this is fixable at home, special tools required etc. or a trip to the dealer/specialist? Cost of parts if anyone's done it recently?

Thanks
 

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That's just the tensioner - so should be easy enough to replace (I have done on other cars but not a m112 enigine, so I can't be sure, but probably just three torx bolts and your away)
 
Does this belt not also drive the coolant pump?
20 Min's of no coolant circulating, not good.
 
Its known as the poly V belt tightener or tensioner. Its a spring loaded device to keep the V belt at the correct tension. There is also a small shock absorber involved to damp out any oscillations. It looks from the picture that the small pulley bearing has collapsed. On some units this can be replaced separately from the main unit- on other models the whole unit has to be replaced- they are not too expensive to replace so I would be inclined to replace the whole unit. While its off I would also check the state of the bushes on the small damper [ shock absorber] unit. If worn best to replace at the same time. You will need a new poly V belt- note these vary in length depending if you have air con or not. Access is a bit tricky and its best to remove the fan shroud to see what you are doing. The fact you have to ask what the unit is for indicates to me it might be best to entrust this to reliable local garage . It doesn't require any specialist tools but a little experience is desirable to tackle the job.
 
OK thanks for the info. So I may have other issues from 20 min driving - car didn't overheat or anything, are they really so fragile?
 
If the car didn't overheat you probably got away with it. Difficult to tell really exactly when the belt gave up the ghost. Only time will tell.
 
OK, thanks.

Quoted 168 for the pulley and 45 for the belt - sound about right?
 
PARTS or parts and labour? Seems a bit pricey to me for parts alone
 
parts alone, inc vat from Merc Grimsby main dealer
 
The fact you have to ask what the unit is for indicates to me it might be best to entrust this to reliable local garage . It doesn't require any specialist tools but a little experience is desirable to tackle the job.

I like that
 
OK, had a search around on the internet including old threads here. Still undecided. 2 Main dealers are quoting same prices so I assume they are correct £210 give or take for the parts. Still waiting on a price from Inchcape. Ebay has a couple of sellers with pattern parts from Germany - under £100 all in shipped. Also tried PFS which are the cheapest at £80 plus shipping.

Has anyone used any of these sources and is it a false economy to use non gen parts?

Quote:
Originally Posted by grober
The fact you have to ask what the unit is for indicates to me it might be best to entrust this to reliable local garage . It doesn't require any specialist tools but a little experience is desirable to tackle the job.

I like that

Yeah, not worked on a car for a few years and this is my first MB......
 
OK, thanks.

Quoted 168 for the pulley and 45 for the belt - sound about right?
Eurocarparts don't list the tensioner for a '99 320 online - but for later models it's £85 (and £20 for the belt). Well worth giving them a ring.
 
Eurocarparts don't list the tensioner for a '99 320 online - but for later models it's £85 (and £20 for the belt). Well worth giving them a ring

Spoke to them this morning, £80 + VAT and the belt is £16 + VAT so £113 all in (plus a fiver for the bridge toll :))

Thanks for the help
 
OK, parts are here, belt and tensioner. Is there an online diagram for the route the belt takes, old one shredded so can't just copy it, may be obvious once I open the bonnet but a picture would be nice. Also, anyone fitted a tensioner who can put up basic steps, looks like the spring loaded pulley is pinned back at the moment - need the proceedure for taking the pin out and letting it take up the tension in the belt please.

Thanks
 
If you put poly v belt tensioner into the search box it should give you the info you need. As has been said it's held to the timing case by 3 ??bolts [ they vary in length] so note their positions when dismantling-you will also have to remove the top damper mounting bolt also and remove the 2 together. Assemble the two new parts[damper+tensioner] together and then replace the new assembly on the car. Once you have routed the belt round all the pulleys apart from the loop round the tensioner place a socket and t bar- on the pulley securing bolt-thats a male torx in your picture but they do vary- and rotate in an anticlockwise direction?? [looking at the windscreen] the pulley on the tensioner arm will move in a small arc allowing you to slip the belt on. then release the tension on the arm and the belt is tensioned correctly.
 
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OK, tensioner is on, it has the tension taken out and is pinned in place so I guess I fit the belt and then release the pin to take up the slack and tension the belt.

No damper on mine, is that due to the cars age ? Should I be looking to fit one for the £30 they cost?
 
Its definitely worth fitting if the tensioner and timing case have the appropriate mounting brackets and it will fit. I am a bit surprised you don't have one but maybe the tensioner design changed .:dk:
 

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