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Weistec M156 Billet Serpentine Belt Pulleys Review - Warning
So, bought a set of billet aluminum pulleys for my 09 E63 M156 in mid 2019 that I installed in the Fall of 2019.
As some of you are aware, the OEM M156 pulleys are plastic, and I figured billet aluminum pulleys would be a nice upgrade. Cost all in was $576 and took a couple hours to install. Have to remove the fan shroud and some miscellaneous items to gain access.
There are four pulleys in the Weistec kit. Below is a pic from their site claiming long life and "High Quality Bearings"
Less than a year after installation, one of the bearings failed, shredding my new belt and leaving me stranded. Had to pay for a tow to my Indy MB shop, buy a new pulley and install it. The shop owner questioned the quality of the bearing and thought he could replace the bearing with an appropriate bearing made in the US or Europe. He removed the circle clip and had one of his shop hands try and press the bearing out, but slightly bent the pulley lip. I complained to Weistec about the bearing failure but they would not replace the pulley because it had been damaged.
This past weekend another Weistec pulley bearing failed in a spectacular manner, shredded another belt and left me stranded (again). This was Sunday, so I was able to pull a used pulley from an E63 at the MB shop and swap it out myself, costing me most of my Sunday afternoon. Below is a pic of the pulley and bearing guts.
Again I complained to Weistec about a 50% failure of their pulleys. Reply was - out of warranty, we will sell you a replacement for a discount. You think I am about to replace one crappy pulley with another?
Ordered a full set of MB pulleys and will install them.
Why on earth would Weistec have fancy billet aluminum pulleys manufactured and install low grade bearings? Buyer beware of anyone considering this "upgrade" from Weistec. I hope the rest of their parts they sell are of better quality.
As stated above, is there any information on the bearng brand and quality? I have learned that the four bearings for $15 are not nearly as good as the single bearing for the same price. The cheap Chinese bearings are crap. I learned that the hard way.
FWIW.
In posts I made years ago I provide links to the bearing manufacturers' data sheets. If you have the outer diameter, the inner diameter, and the width of the bearing in your pulleys you can go straight to the manufacturer's data sheets and purchase a high quality bearing once you have the data. It's may be less trouble for you.
from what i've seen...all aftermarket aluminum pulley's utilize the wrong spec bearing. its a mid priced bearing that has the incorrect RPM specification.
if you're able to post the spec and it matches what i've used, i'd recommend going with the same NTN bearing i used. its the highest rated RPM off the shelf bearing available. the factory pulley's use a custom spec bearing at an even higher RPM range which is actually correct for the M156's high rpm operation.
Originally Posted by hachiroku
previous to the set of new OEM pulleys I killed at 12k the ones prior lasted 40-50k? I changed them out for safe measure not because of a failure. I do drive a lot more harsher than I used to. the ones that failed at 12k failed on a double gear kick down. that jolt of torque just broke the bearing support within the center of the pulley. It also took out my thermostat and housing.
here are the specs of the bearing.
NACHI 6203NSE bearing d - 17 mm
D - 40 mm
B - 12 mm
C - 12 mm
r min. - 0.6 mm
da min. - 22 mm
Da max. - 35 mm
ra max. - 0.6 mm
Weight - 0.065 Kg
Basic dynamic load rating (C) - 9,55 kN
Basic static load rating (C0) - 4,8 kN
(Grease) Lubrication Speed - 12000 r/min
(Oil) Lubrication Speed - 21000 r/min
this is what i'm replacing it with
NTN
6203LLBC3/EM
Type
Deep Groove Ball Bearing
Bore Type
Round
Material
High Carbon Chrome Steel
Cage Type
Pressed
Cage Material
Steel
Ball Material
Steel
Limiting Speed - Grease
18000 RPM
Seal Type
Non-Contact
Seal Material
Nitrile Rubber
Precision
ISO Class 0
Configuration
One
Factor
12.8
Radial Internal Clearance
C3
Static Load Rating
1030 lbf4600 N4.60 kN
Dynamic Load Rating
2160 lbf9600 N9.60 kN
Enclosure
Double Sealed
Weight
0.141 lb0.064 kg
Operating Temperature Range
-40 to 250 ºF-40 to 120 ºC
Dimensional Specifications
Single Row Radial Ball Bearing - Double Sealed (Non-Contact Rubber Seal) - Dimensions
d
0.6693 in17.000 mm
D
1.5748 in40.000 mm
B
0.4724 in12.000 mm
r
0.0236 in0.600 mm
r1
0.0197 in0.500 mm
da min
0.8268 in21.000 mm
da max
0.9055 in23.000 mm
Da max
1.4173 in36.000 mm
ras max
0.0236 in0.600 mm
So this is what happened to me this weekend with the top left idler from Weistec, catastrophic failure, which luckily I heard happen and managed to save the belt and everything else.
I’ve contacted Weistec but I don’t expect any action, in fact I don’t want their pulleys, I just want them to know and fix their design.
Can anyone tell me the part numbers for the OE pulleys that the Weistec ones replaced? I want to slap on a brand new OE set.
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d - 17 mm
