Tensioner help! - PeachParts Mercedes-Benz Forum

drbrandini · #1 12-22-2002, 09:55 AM

Can I remove my serpantine belt by loosening the alternator, installing the belt and retightening the alternator? Or do I absolutely have to use the belt tension adjusting device?

Thanks again,

john90290 · #2 12-22-2002, 10:11 AM

I have a copy of the manual and it offers up that suggestion of removing the alternator bolt to slacken the belt enough to remove and replace. Why the hesitation on using the tentioner? I would make a drawing of the serpintine belt pathway if you do not have the manual. I recently replaced the tensioner in my 300e and referred to the manual sevral times for the correct routing.

good luck.

drbrandini · #3 12-22-2002, 11:09 AM

Thanks,

I am familiar with the routing, I would just rather loosen at the alternator since the belt tensioners are known to strip and whatnot. This way I wont have to readjust the tensioner, just tighten the alternator and go.

Thanks again

Mick J · #4 12-22-2002, 11:48 AM

You'll have a job getting the alternator back on without slackening the belt. Just remember to loosent he big (17mm?) bolt through the middle of the tensioner before touching the adjuster rod. If you do break it they cost peanuts anyway.

drbrandini · #5 12-22-2002, 01:26 PM

I am not certain how the pointer on the adjuster works can someone explain this to me. If I loosen the 19mm nut in front a couple of turns then loosen the top not a few turns is this all I need to do to get the belt off? THen to retighten do I tighten until there is @ 1/2 inch of play either way on the belt?

Mick J · #6 12-23-2002, 04:28 AM

The purpose of the pointer is to measure the angle through which the rubber torsion spring in the middle of the tensioner is turned. You don't need to measure the slack in the belt.

To get the belt off, loosen the big bolt then slacken the tensioner. Watch what happens to the plastic pointer as you do this.

When it's all back together and the belt completely slack you set the plastic pointer to the end of the cast triangle marking (can't remember which end but you'll soon work it out if you noted what heppend when you loosened it) then tighten the adjuster until it points to the other end. Then tighten the big bolt.

drbrandini · #7 12-23-2002, 09:00 AM

Thanks Mick

drbrandini · #8 12-23-2002, 03:27 PM

Mick,

After much trouble I finally freed the fan pulley, I then loosened the 19mm bolt, before trying to loosen the adjuster nut up top. I decided to pull on the belt it was a bit snug but I managed to pull it off without adjusting the top..Do I still need to loosen it so that the belt will go on without trouble? I am also looking for so torque specs for the tensioner shock and idler pulley as well as the 4 mounting bolts for the fan pulley. Any idea where to get these?

Thanks again you've been I big help.

anthonyb · #9 12-23-2002, 09:15 PM

I would loosen the tensioner before installing the belt. The problem is not so much with the adjusting bolt stripping (so long as the big 19mm bolt is unscrewed a couple/few turns), but with old tensioners losing their elasticity. If the tensioner doesn't slacken as you loosen the adjusting bolt, then your tensioner is bad.

Torque on the damper is 21 Nm at the bracket. According to the manual, torque on the fan pulley is 10Nm. If you have a torque wrench that's accurate this far down the scale, you can try it - I used one that wasn't and my pulleys ended up wobbling. I ended up tightening up as far as I could get them with a socket wrench - this might have been a little too much, but took care of the wobble.

-anthony

drbrandini · #10 12-23-2002, 11:02 PM

thanks,

I have now loosend the adjsuter nut by several turns and it is loose. But I don't understand how to retighten the tensioner. I see the triangle but I dont see a pointer or anything that looks like a reference point for the triangle. Should I now just put the belt on and retighten a couple of turns (the same amount as it took to loosen it) ?

drbrandini · #11 12-24-2002, 07:03 AM

Quote:

Originally posted by Mick J

When it's all back together and the belt completely slack you set the plastic pointer to the end of the cast triangle marking (can't remember which end but you'll soon work it out if you noted what heppend when you loosened it) then tighten the adjuster until it points to the other end. Then tighten the big bolt.

Is It possible I dont have a plastic pointer? I dont see anything like this...The tensioner was replaced about a year ago but I am starting to have my doubts about the shop that installed it since all of this...

Gilly · #12 12-24-2002, 07:39 AM

Absolutely it's possible. it's a completely seperate piece. You can order it if you want it on there. You can see where it goes. It snaps onto the tiny serrated teeth you can see between the front bracket and the tensioner itself, kind if down in that groove.
The bracket will need to be removed to install it though, which involves removing the belt pulley that runs the cooling fan, and the pulleys for the power steering and water pump. There are 3 bolts that hold the bracket on, one over near the crank position sensor, and 2 over near the power steering reservoir. The slightly tough one is the bottom one by the power steering, as it has a nut on the back side of it that needs to be held with a wrench.

Gilly

drbrandini · #13 12-24-2002, 03:43 PM

Thanks Gilly,
Rather than do all of that work, how can I tighten the tensioner to the correct specs without the pointer. I remember that it only took about 1 1/2 turns to loosen the adjuster nut. Should I just tighten it 1 1/2 turns when I get the belt back on ?

Gilly · #14 12-24-2002, 04:05 PM

That I know of, the pointer is the only true way of knowing.
I would be satisfied, in the absence of the pointer, just going by if the belt "feels" tight enough.

Gilly

drbrandini · #15 12-24-2002, 08:39 PM

Thank You Gilly,

Merry Christmas