I have a 93 2.6(m103)How do i remove the serpentine belt, Can i just replace it by slackening the bolt of the alternator and pull it until the belt loose the tension.Can somebody tell me the best procedure.Thanks

Ron

Ron,

I didn't know the M103 made it to 93. If you're not familiar with this engine, be ready for the most complex belt tensioning system you've ever seen. I can only wonder what the newer engines are like.

In any case, to remove the belt, loosen but do not remove the big headed bolt (19mm?) in the center of the tensioner pulley just to the right of the power steering pulley. Then relieve the belt tension by loosening the tensioner. The tensioner is that hollow 13mm hex head thing sticking up behind the tensioner pulley.

On the tensioner body is a set of marks used to set tension. On mine, there's a pointer that moves with the tensioner, and a set of marks that look like a right triangle and a post (hard to describe in words). As you tighten the tensioner, the pointer will move along the triangle. Proper tension is set when the the pointer is between the triangle and the post. If the belt still feels loose, then the tensioner is bad. Which makes me wonder why MB employed this system.

There's a little shock absorber just beside the oil filler cap. It is part of the belt tensioning system. I don't know the consequence of a bad shock absorber, but it won't be a loose belt.

Take note of how the belt is routed before you remove it. It will go on the wrong way... maybe several wrong ways. There is also a sequence for threading the belt on the pulleys. I don't know how critical the sequence is. I got my belt on without following the sequence, and it's held for almost a year.

Sixto
91 300SE (M103)

Belt replacement
 

First remove the fan fan/clutch and the do the described operation above

Doh! Of course. Good catch, Stan.

Thank you

I haven't had to remove the fan or fan clutch to replace the serpantine belt. Just loosen the tensioner near the top middle of the pulley system. Make sure you have a diagram or the belt routing available because your going to need it. I start the belt on the power steering/water pump side then work my way through the cranshaft, fan, idler, air pump and pull it over the alternator pulley last. Have fun and good luck.

I already loosen the big head bolt(19)4 turns, But when i turn the tensioner screw(13 hex)counterclockwise nothing happen I mean the belt is still tight and I can turn the tensioner screw by hand and I noticed that when i turn the thread of the tensioner screw is not moving or turning,Do i have a problem with the tensioner screw?Help me out i want really want to change this.I included the pic.Thanks

http://retrospectstudio.tripod.com/lwf0.gif
Ron

[Edited by ronald_m on 06-13-2001 at 02:11 PM]

Ron,

The rod is not supposed to turn.

The tensioner keeps pressure on the belt even when not fully tensioned (I told you the system was complicated) so don't expect the belt to sag as you loosen the tensioner.

Loosen the tensioner (#5) until it lifts off the bracket (#12). On my car, the tensioner lifts several cm off the bracket, but gets really difficult to turn before it comes off the rod. Be careful when you loosen the tensioner -- if the rod comes off the tensioner body, it takes some doing to get it back on. Press on the tensioner pulley (the small pulley beside the power steering pulley) until you can remove the belt.

Some people claim they can replace the belt without removing the fan. I must have two left hands.

Sixto
91 300SE

Sixto,I think that is my problem the rod comes off the tensioner body, Probably that's why i can turn the tensioner screw by hand.Where do i lift the tensioner screw to the right?Thanks

Ron

If the the rod moves only a little, it's still attached to the tensioner body. Don't move it any more.

I don't understand the question "Where do i lift the tensioner screw to the right?"

If the rod is loose enough to wiggle, and the tensioner is not touching the bracket, then that's enough.

Turn your attention to the tensioner pulley. You should be able to move it by hand at this point.

... Conversely, my two left hands replaced the tensioner assembly without touching the power steering pump.

Sixto
91 300SE

Well, it seems a lot is going on in this thread. Ron, if the tension adjusting rod (screw) has come off the tensioner, then the rivet which holds the rod to the adjusting collar gas broken away. The only way that the adjusting screw can be removed is to have clear access to the rear of the tensioner assembly..which means the tensioner lock bolt would have to be fully removed and the tensioner body would have to be separated from the supporting brackets. Therefore, if your adjusting rod (screw) is off the collar (round casting with two flat sections which mate with the tensioner body), the rivet which hold the rod to the collar has broken away. If this is the case, the replacement rod and collar (an assembly consisting of the adjusting rod riveted to the collar) can be purchased from the Parts Shop here for about $12.00, Also comes with a new adjusting nut. Check under FastLane, online catalog, your year and model, cooling system, accessory belt tension adjust. Look at the picture and you will see what I am talking about. Good Luck.

Jeff,Wow that was too complicated for me but im gonna try it tomorrow.Do you have a picture of what you're talking about?

Thanks for all your help.Im gonna try my best to replace it tomorrow.

Ron, read this. Follow the trail to what you are lookin for.
Check under FastLane-> online catalog-> your year and model-> cooling system-> accessory belt tension adjust. Look at the picture and you will see what I am talking about. Good Luck.


[Edited by jeffsr on 06-14-2001 at 12:00 AM]

Jeff,

> if the tension adjusting rod (screw) has come off the
> tensioner, then the rivet which holds the rod to the
> adjusting collar gas broken away

Interesting point. On my car, I can disengage the assembly as shown in Fastlane from the tensioner with the tensioner in place. Difficult as heck to get it reengaged in situ.

If the rivet is broken, I imagine the rod could be lifted off the engine, right? With the rivet in place, the tension adjusting rod won't go far from the tensioner.

Sixto
91 300SE

Correct. If the rivet is intact, the rod will stay with the collar. If not, you still will have to remove the top of the bracket which the adjusting nut bears against. Only then can the adjusting rod/nut be removed completely.