Tensioner Pivot Lever - Lube it? - PeachParts Mercedes-Benz Forum

TMAllison · #1 07-01-2006, 04:40 PM

Am installing a new tensioner pivot lever on my 99 E300 in an attempt to get rid of a nusiance vibration at the serpentine belt.

There appears to be a coating applied on the inside surfaces of the new pivot lever.

Need to know if I should lubricate the inside of the lever or not before installing the pivot pin?

If so, with what?

t walgamuth · #2 07-03-2006, 09:53 PM

if it is a moving intersection, i would squirt some white lithium grease in it.

tom w

Duke2.6 · #3 07-03-2006, 10:04 PM

If you're talking about the accessory drive belt tensioner, no lubrication is required and any petroleum based products like grease will increase its rate of deterioration.

Reusing the old tensioner unless you test it for proper function is a recipe for rapid failure of a new belt.

Search "failure analysis" under my handle in the archives if you want to understand this device.

Duke

TMAllison · #4 07-03-2006, 11:25 PM

Duke - I think the tensioner you discuss in your past post is very different than my 606.962.

Mine has no rubber parts or bearings. Is cast aluminum, bright polished on the interior with split metal sleeve inserts that MAY have some sort of coating applied on them which is what caused my confusion as to how to handle.

I finally elected to use a very fine coat of grease as the pin was pretty snug going through the tensioner.

Attached is a diagram (hopefully). Is part #5. A steel pivot pin with 17mm hexhead attaches it to the block. Timing chain is visible behind the threaded hole.

Found my new dampner shock had completly lost its charge so replaced with teh old one that still had resistance. Plan to get another new one this week.

Still have vibration at cold idle but is better.

Would appreciate further comments.

Duke2.6 · #5 07-04-2006, 09:51 AM

I wish my M103 had a steel spring tensioning element rather than the hokey rubber bushing. It would save M103 owners a lot of grief.

If item 17 is a "pivot" rather than a lock bolt as in the case of M103, and the tensioner is free to rotate about this pivot when torqued to spec, then a good lubricant would be graphite, which is an excellent lubricant for high load low velocity sliding surfaces.

A convenient form is Lock-Eze, which is an emulsion of spherical graphite in the petroleum distillate carrier that evaporates. It's available at most hardware stores.

If the belt vibrates you might also try replacing the spring in addition to the damper.

Duke

t walgamuth · #6 07-04-2006, 10:40 AM

it also could be the bearing in the pulley going bad.

tom w

TMAllison · #7 07-04-2006, 12:27 PM

Thanks both.

1) The tensioner spring broke 6 months ago so is basically new.

2) The belt was replaced as general maintenance ~4 months ago.

3) The dampner shock was replaced ~2 months ago.

The sealed bearing ring on the tensioner pulley (actually a roller) operated very smoothly when I swaped it over to the new pivot arm. The new dampner had lost it's charge so the old one was put back on (when comparing new vs. old 2 months ago the amount of resistance was basically the same. ~20-25lbs by feel).

Darn thing still vibrates at idle although it IS 50% less than before.

Before replacing the pivot arm I had tried subtly crimping the ends of the spring, thereby shortening it to increase it's tension. Guess I will try spreading it back to its original position next and then openning it further to decrease tension if that does not help.

Beyond that I am out of ideas.

Duke2.6 · #8 07-04-2006, 02:36 PM

Make sure the belt is the correct length, which should be listed in your owner's manual or applicable maintenance/service literature. Too long a belt means the tensioner won't provide enough belt tension.

BTW the tensioner includes a "damper" - no such thing as a "dampner", and a damper damps and provides damping, not dampning or dampening.

Duke

TMAllison · #9 07-04-2006, 10:53 PM

Thanks for that.

The specified belt length is listed as 2140mm. The installed Conti belt commonly sold for this model is 2130mm which is 3/16" smaller diameter.

Reducing spring tension caused increased vibration.

TMAllison · #10 07-09-2006, 10:27 PM

Confirmed with dealer that there are 3 belt lenghts specified for the E300 and that based on VIN the 2130mm belt lenght I have currently installed is correct for my car.

Replaced the damper shock with another new one the other day with little or no effect on vibration.

Will probably replace the spring tensioner this week as I have tweaked mine trying to change the amount of pull it exerts.

After that I guess I will have to learn to live with the darn vibration unless someone can chime in with something constructive???

hookedon210s · #11 07-11-2006, 06:32 AM

I am unfamiliar with this tensioner but it would appear that bolt 17 and washer(?) 29 would be possible wear items. It may make sense to replace these. Mark

TMAllison · #12 07-11-2006, 01:22 PM

The pivot PIN and the washer are both hard steel.

The sleeves inside the cast alum pivot arm are a softer metal that appears to be designed to be the wear surface. There are no bushings or bearings as others have suggested.

In speaking to Phill at Fastlane he said he had never ordered a pin before and wasnt sure if it was even stocked in the US.

TMAllison · #13 11-19-2006, 02:05 PM

For future reference, resolution of vibration and subsequent failure of numerous components at the belt tensioner of my 99' E300 was caused by bad motor mounts.

The vibration present at the tensioner was bad enough that 2 shock dampers overheated and lost resistance and the lower bushing of a 3rd damper melted and came out of it's pressed in housing; one spring tensioner broke, the interior wear surface of the pivot arm wore out and the 2130mm belt was stretched to 2156mm.

The diagnosis that the problem did not originate at the tensioner was arrived at when the belt was removed, the cold engine was run for 60 secs and the darn vibration remained.

The motor mounts (looked at early on) were fine visually and still had 16mm clearance when measured (min spec is 13mm), later when the motor was lifted 1/4" and they were looked at a second time it was evident the tops of the mounts had cracked and were separating. These cracks were hidden as the weight of the motor compressed them making them appear visually OK. Use of a large rubber bushing between the jack and engine confirmed the bad mounts.

The additional vibration caused by the bad mounts apparently added to the damping duties of the tensioner causing those components to fail. Very, very misleading.

Many thanks for the advice received from MBDOC and especially GILLY who graciously provided me assistance in ruling out components one at a time. Thanks guys.

deltajetfixer · #14 11-19-2006, 05:57 PM

Quote:

Originally Posted by TMAllison

For future reference, resolution of vibration and subsequent failure of numerous components at the belt tensioner of my 99' E300 was caused by bad motor mounts.

I know you'll sleep better now that this has been resolved. Would've driven me nuts!
Is this the second or third set of mounts? Mine were done at 45000 when the dealer Starmarked mine. I'm just shy of 100000 and was wondering how I could check the mount "freeplay". I'll try the lift check you described.

TMAllison · #15 11-19-2006, 07:33 PM

This is the first set of mounts since I got the car at 109K. Cant say for certain but believe what I removed was OE. Both old mounts have a MB logo and what appears to be a 98' date stamp (mine was produced in 98). Neither MBDOC or Gilly felt the W210 was an exceptional mount eater contrary to what I found posted in threads from 3-4 years ago.

When lifting engine be careful not to lift too high, would be a shame to split a good mount by using too much force.

FYI - I outlined my expiriences R&R'ing the mounts in this post. http://www.peachparts.com/shopforum/showthread.php?t=170651