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Old 10-08-2001, 04:12 AM
anthonyb anthonyb is offline
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Join Date: May 1999
Location: Sacramento, CA
Posts: 1,472
Mike: thanks for all the help. That last bit of advice helped quite a bit, though I still found that loosening the last bolt on all of the pulleys was much harder than the first two or three.

Anyways, thanks to all of the advice here and in the archives, a few skinned knuckles, and about 10 hours of labor (quite a bit more than the three or four my mechanic figured it'd take), I did manage to get everything off and back on, hopefully without screwing something else up. Here's the procedure that ended up working for me (after some backtracking and head scratching):

1. Remove the fan shroud and place over the engine fan. A long-handled screwdriver is useful for prying the two metal clips off.

2. Unbolt and remove fan/clutch assembly. Look behind the pulley for a slot, rotate the fan/pulley until one of the pulley holes lines up with the slot, insert a rod-like tool into the slot until it engages into a hole. 8mm socket/allen wrench/MB tool takes off the single center fan bolt. According to information found in the archives, after removing fan/clutch assembly, keep fan clutch in a VERTICAL position...

3. Remove fan shroud (on the early 300Es, the fan must come off first... also, takes a minute or two to figure out how to sneak it past the hoses and oil cooler lines.)

3. Break loose the bolts on the engine fan pulley, the water pump pulley, and the power steering pump pulley (very little clearance on that last one). Bolt sizes were 10mm, 13mm, 13mm respectively, I think. Mike's tip on using two wrenches works well, though the last ones to be loosened still gave me problems. Also, don't forget to use the fan pulley holder at this stage - I did, and I regretted it after losing some skin.

4. Loosen the 19mm bolt securing the belt tensioner (right below the water pump pulley) several turns.

5. Unscrew the 13mm tensioning nut (right next to the power steering filter).

6. After first making note of the belt layout, remove serpentine belt. It took me a lot of effort to yank mine off, since steps 4 and 5 did little to slacken the belt.

7. Remove the fan, water pump, and power steering pulleys. The fan pulley was wedged pretty tightly onto the bearing, but it does come off.

8. Unbolt the top of the tensioner damper (13mm bolt and nut).

9. Loosen the 11mm (I think) bolt at the bottom of the tensioner damper.

10. Remove the 19mm securing bolt.

11. Remove the three 13mm bolts securing the Y-shaped bracket to the front of the tensioner. (Here is where I have a hard time seeing how someone could do this job alone - the bottom right bolt has a nut on the other end that seems to only be accessible from the bottom. It takes some finding after crawling underneath with a flashlight, and I can't see how anyone could unscrew the bolt and the nut at the same time.)

12. Remove the Y-bracket.

12. Work the tensioner + damper out from behind various bearings and accessory components.

13. Make note of the orientation of the tensioning nut/screw assembly, remove, check for stripped threads, reinstall. (Now would be a good time to do some engine component cleaning, if so desired.)

14. Install tensioner onto tensioning nut assembly. Since I had a hard time getting the bolt hole in the tensioner and the assembly behind it to line up, I would recommend temporarily threading in the 19mm bolt to check alignment. Also, the tensioning nut should be in the most "untensioned" position (otherwise, you'll have an even harder time getting the holes to line up, among other things).

15. Install tensioner damper.

16. Apply some RTV silicone sealant to the left-most Y-bracket bolt hole and the underside of the corresponding bolt head.

17. Remove 19mm securing bolt, transfer plastic pointer from old tensioner to new tensioner, install Y-bracket.

18. Screw in 19mm securing bolt (not all the way).

19. Attach belt pulleys. Don't forget to use the fan pulley holder! Also, when I was trying to push the fan pulley back onto the bearing bracket, I placed an aluminum block across the pulley (a thin piece of wood would work too) and used a wrench to hammer it back on.

20. Install new belt. I'm not sure what the best way is to do this - I found that the new tensioner didn't leave enough slack to loop a fresh, unstretched belt around the pulleys. I tried the alternator trick (remove bottom bolt, loosen top bolt. rotate alternator up and to the side), but found that, after attaching the belt, the belt tension pulled the alternator forward enough that it no longer fit between the engine brackets. I eventually had to enlist additional brute force to yank the belt over the last pulley.

21. Tighten tensioning nut until the pointer reaches the tip of the triangle or the belt tension is to your satisfaction. (I ran into an issue where the tensioning nut ran out of travel before the pointer reached the triangle tip! I backed off the tensioning nut a turn or two, then secured the whole assembly..)

22. Tighten 19mm securing bolt (75Nm).

23. Tighten pulley bolts.

24. Install engine fan, 45nM torque I think.

25. Install fan shroud. On the single-piece shrouds like mine, I find it works best to fit the top tab into the slot, then get underneath and slip the bottom two tabs into their respective slots. The bottom tabs appear to be slightly shorter than the top one.

26. Insert shroud clips, and you're done!

Hopefully, this is fairly accurate. Let me know if I missed something, because that means I misinstalled in on my car!

Thanks for all the help,


Last edited by anthonyb; 02-18-2004 at 11:18 PM.
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