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2015 GLA45 serpentine belt replacement

102 views 4 replies 3 participants last post by  sam45AMG  
#1 ·
Replaced the belt at about 82k miles with MB one. Probably the cheapest critical MB part I have ever purchased, less than $ 18 I recall.
Tool used to un-tension the tensioner: Amazon.com: 4346 Serpentine Belt Replace Tool for Mercedes Benz M270 Engine Belt Tensioner Wrench Serpentine Belt Tool MM# 270589000700 : Automotive

The tool didn't fit between the fender and the tensioner so I had to file off some of the tip to get it to actually fit and be able to install from below.

Once the clearance issue was fixed I couldn't get it to line up properly and I am not sure if the old belt was just so stretched or if the star on the tool was not attached properly, but I had to notch out the undertray to get enough angle to insert it and have enough swing to release tension. Once the new belt was installed, I certainly had enough angle to get it out so I think that the old belt stretched quite a bit, which makes me think I should just replace this every time the spark plugs are due.

You can see the hole in the old belt in the pics.
 

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#2 ·
Yeah good idea to replace often. Having had a serpentine belt snap on me it's no fun on a vehicle that has as many electrical systems as ours. After inspecting mine it had very little wear, it just let go. My tech guy says these new belts don't show wear like the old ones did so inspection of condition is not as helpful.
 
#3 ·
Agreed, the manual just says to inspect it, not a definitive mileage or time to replace it. Glad I did when I did, not sure how much longer it was going to last. Once it was off, I noticed a lot of cracks and other small damage that most likely would not have been found by looking at it while installed.
 
#4 ·
Thanks for the post. I have a 2018, so it likely needs to be replaced. Are there any other tips? How long did it take? This should be a simple job. The pics with amazon tool help me visualize the job. I assume the tensioner can be released once the old belt is off (without pinning) to route the new belt? Did you replace any rollers or tensioners?
 
#5 ·
It took a few hours but here is why:
1. I didn't realize that the tip of the star key was just a tad too long to be able to get a "straight on" angle to the hole until I had exhausted all other options.

2. It took a little time to file down, check, file down more, check again, etc.. Once I was able to get the tool key inserted, the swing angle was far too short to loosen the tensioner enough to get the belt off. In order to get enough swing and movement on the tensioner I had to insert it one tooth rotated from where I currently was. In order to do that, I had to cut into the undertray to get that angle. Maybe it was due to severe stretching of the belt but I think it is due to the position they welded the key onto the arm. If they had welded it slightly clocked a few more degrees one way, I probably would have been able to get it without notching the undertray. I am sure if you get the official one from MB, it will be perfect.

3. Had to figure out how to route it correctly and keep it on the pullies while attempting to get it installed. If it slipped off the alternator pully, I would have to get out from under the car and put it back on from above. Did this a few times.

I don't think I removed the tool prior to installing the new belt, but maybe I did. What I can say is that once you get the belt off and release the tension, If the tool goes all the way and comes in contact with something, then I would not remove it but if the tensioned is fully released and it is not touching anything, then you could remove the tool and install it in the same position.

No, I did not replace any pullies, rollers, or the tensioner. Just replaced the belt.

If I had to do it again, It wouldn't take even half as long but still longer than other vehicles. On my 03 toyota corolla, I can replace that belt in under a few minutes, probably can do it in under 1 minute with a few practice runs.

Tips:
Plan for a few hours or more, don't rush it. Being able to get under the car safely will help save a lot of time; I had the front on jackstands. If something isn't working right, take a step back, look at it again, and see what you can see. Be patient, try not to get frustrated, it may take a few attempts.

Let us know how it goes.