Friday, September 11, 2020

At what point do you choose aftermarket parts over dealership supplied OEM? When it all goes wrong, apparently.

I'd like to preface this by saying, Mercedes corporate customer service lines are absolutely phenomenal. I have nothing but praise, especially for you Denise!, with how they handle these calls. Unfortunately, you get dealerships and parts managers who refuse to stand behind the products they sell and it certainly leaves a sour taste for the brand as a whole. Ultimately, there are aftermarket company's that sell equivalent parts to Mercedes, that will actually honor their warranty.

I got into the habit of carrying spare parts in my vehicles that would render them immobile on longer duration trips. At the very least, enough to get them mobile enough to drag them to a point where a tow truck would be able to get to it. As you can only expect a gelandewagen to go where a gelandewagen goes, the middle of nowhere, you can also expect there to be astronomical recovery costs should there be someone around to actually recover the vehicle.

In my case, this didn't necessary happen in the middle of nowhere, but it happened in a location where the tow bill would've been absolutely obscene and in a location where there's not a single capable facility to handle the work. You're probably going to wonder why, in the picture below, there's smoke billowing out of the passenger rear wheel. You're probably going to ask yourself why that same wheel also is cambered inwards on a solid axle truck. To be short, my wheel was only being retained to the truck by the brake caliper..... total bearing failure...of a brand new bearing...from the dealership...installed by I must not know what I'm doing.

So what happened? Wheel bearing was absolutely obliterated. Just about nothing was recognizable, couldn't find a single in tact roller for either side of the bearing, the outer race got mangled enough to where it was wedged into and locked up inside of the axle housing.

This is where me carrying spare parts comes into play. Prior to this trip, I went through and rebuilt and resealed the entire rear axle. Something I've done on dozen's and dozen's of G's around the country. It's the second time I've done it on my own G, I believe a bit in a bit of overkill to prevent any failures down the road. Who would've thought that my own attention to preventive maintenance would be the thing that strands me. 

I managed to do 95% of the job with a hammer, chisel, and a WOOD saw. That's right, I was hand sawing away a the frozen race to try and cut reliefs into it. Ultimately, higher powers forced me to call it a night and the next morning, a home depot was found and a sawzall and generator were rented to try and speed up the relief cutting. After another couple hours of cutting reliefs and using a grinder to sharpen some chisels, I managed to get the remnants of the bearing out to try and get the axle back into the truck to try and get me home. 

Here's what's left of the parts I had to extract from the axle housing before I could attempt putting a replacement bearing in place.

What caused the failure? Well I don't have the exact cause, because this is the first time I have ever seen a failure like this happen to one of these bearings. I would try to pin it on installer error, but my process is the process Mercedes themselves specifies. I have all the factory tooling for pressing the bearing on, have the factory lock ring wrench, and I have the entire WIS documentation on a moments notice to confirm installation procedures. You can even see where I peened the lock ring to prevent the lock nut from backing off... every last detail was done correctly. 

I could only make two assumptions - lack of lubrication or the bearing was bad out of the box in some manner. I'll discuss both possibilities below.

By now you've probably looked at all of these pictures and are wondering how on earth something like this could've happened. How could this bearing, which for all intents and purposes has a reputation of lasting hundreds of thousands of miles without failure, fail on my truck after 2500 miles? What could've happened was a lack of lubrication, which wasn't the case for me. These bearings are designed to be lubricated by the gear oil that gets splashed up into the axle tube. The way the entire failure unfolded was within about 10 minutes and 6 miles, that's all it took from first signs of failing to total failure. When I finally pulled over, the gear oil that was supposed to be lubricating the bearing, was seeping out from around the bearing retainer onto the axle tube. Not only was it seeping out, it was catching fire every time the fluid dripped. Incredible heat build up in that axle. 

What do I believe actually happened? The bearing cage was broken out of the box and the heat built up and stress involved in carrying a fully loaded G around was enough to lock up the bearings. Simple. 

That's right, this simple brown cage, made of PLASTIC, was the cause of failure for my bearing. If in any way, this part fails, you've just destroyed the bearing race, the rollers, etc. Ridiculous, isn't it? 

My intention here isn't to throw anyone in particular under the bus. As much as I'd love to be a full blown Karen about the situation for how poorly the parts "director" for this particular dealership was in contact with me (aka not at all), I won't throw them under the bus. I would've loved if the dealer stood behind their warranty and guarantee of quality, but unfortunately it can't be helped now. All I can do is move on, fix the truck, and never recommend this dealer. 

For the record, the parts damaged:

902 350 1410 - Repair Kit x2 
017 981 4605 - Axle Bearings x2 
(2 because my spare parts had to be used to limp the truck, they have to be removed to do the repair correctly)

Parts damaged as result of failure:

902 357 1919 - Bearing Retainer 
902 357 0226 - Lock Nut 
463 357 1001 - Axle Shaft Right 
ABS Sensor (melted)
Brake Wear indicator (melted)
parking brake pads delaminated from heat
brake pads delaminated from heat
rotor is now warped (and still blue from the heat)

So my roughly $130 preventive repair parts purchase and install has now cost me roughly $2k in parts cost to repair correctly. The real question here and some food for discussion, why should I continue buying genuine parts if the "warranty" they supply for the parts would only apply when installed at a dealership? Why should I be buying parts that, at this point, are of questionable quality from the dealer when I could buy those same questionable parts from the actual manufacturer (SKF, which warranties their bearing regardless of who's installing by the way). 

Mercedes, I love you, but start getting after your dealerships. 



Post a Comment