A couple months back we bought a 2017 GLC43. During the test drive there was a squeak and I thought nothing much of it. Just thinking it's a dry hood bushing.

Fast forward chasing the squeak I finally got it completely taken care of. First I changed the lower control arm. Squeak was still present. Next I changed the two front air struts and the squeak was mostly gone. It used to squeak all the time over bumps then just major ones. Yesterday, I injected the upper ball joint with grease and now it's completely quiet. It even drives like a different car.

I found the upper ball joint issue after purchasing a stethoscope from harbor freight. Had my brother pushed down on the suspension while checking multiple points of the suspension. The loudest part was at the upper ball joint. That's when I decided to try and grease this ball joint vs changing out the control arm.

To inject grease into the ball joint I bought a needle that connected to a grease gun from amazon. Prime the grease to get to the end of the needle then inject it into the boot. Just fill until it firms up the boot, don't overfill because it will leak out when you pull out the needle. Clean where the injection hole is with a cloth and alcohol and put on some RTV to seal the hole.

Now the GLC drives like a completely different car.

Tonight I will go thru and put grease in all the other boots in the suspension. I am guessing from factory the ball joints did not have much grease in it. That's why there is such a high/pronounced failure rate on the GLC/C class ball joints.

I hope this help others as it has been a stressful 2 months chasing down issues. Everything done helped the car but I would never thought at 80K miles all these issues are present.

I've own/owned several Rams, Mercedes, Lexus, Chevy's and Fords. This is the first brand to have suspension issues this early on. All other vehicles would be 120-140K miles before ball joints needed address. Currently the highest mile vehicle is a 2015 Ram 1500 with 138K miles. The air suspension finally started leaking at 125K miles and I've converted it to standard suspension. My other Mercedes I've had to change out a handful of item like control arms/axle seals at 75K miles for the 2013 E550(65K miles), 2012 CLS550- 60K miles sway bar link and rear airbags, 2014 - 70K miles CLS550 sway bar links, 2015 C250 - 45K miles engine/trans mounts. Mercedes are very nice vehicles but I would never thought they require parts changes so quickly. Also all of the Mercedes have some cam cover leaks(ridiculous that this is even an issue while all other brands have been spotless on oil leaks).

 

Glad you figured it out, thanks for posting. Some C 43 owners (so the sedan) also have a squeaking issue so hopefully your post will help.

 

yes thank you very much! I tried grease in the bushings on my lower control arms but I’ll try the uppers now.

 

I do hope this helps some members. We went from owning Lexus to Mercedes. Lexus has it's own set of issues and is not as problem free as it's seems. I've owned the LS430, SC430 and GS350. All had things that needed to be addressed but non needed suspension components.

 

This is true.
I saved a lower control arm ball joint, which was squeaking, now good working.

I injected all ball joints of Glc.

A narrow needle, like 1mm, is a little better to cover the injection hole with my polyurethane caulking.


Upper

Sway bar link

Lowers, tierod

 

Very nice, good job! Thanks for sharing.

 

SN202020,

Thanks for sharing and the details. I’ll give it a try.

cheers

 

Thank you for sharing.

For my case, the top control arm rubber boots were not enough to cure the squeaking noise.

I did a total of 6 rubber boots on each side using syringe without needle, roughly 6ml of grease is good enough for each boot and massage the grease around the boot; pumped 12ml and the grease would overflow out.

The first test drive ~30km was awfully quiet; however the squeaks came back a little on the second short drive.
The next morning, the squeaks came back with a vengeance! Every single small bumps where previously had no squeaks produced a soft squeak now; and the larger bumps produced squeaking harmony tones..

Checked and some stains of grease seen from the hole patched with liquid gasket. Will repack the grease again after a few more drives and see how it goes.

 

Can you seal hole with Loctite super glue or rubber bond, mat help. ??

 

Each hole was sealed liberally with liquid gasket; may not fully cured as I needed to use the car shortly after completing the grease injection.

 

Something else I did as well was to lubed all the rubber isolating joints with a spray silicon spray. It resolved all the minor squeaks I got from time to time. I did this twice. Once sprayed I drove the car to let it cycle. Then I did it again and drove it again.

I usually run thru the automatic carwash and it sprays the undercarriage to remove grim. It's possible that this dries out the rubber components or makes it too clean/dry and the squeak happens. I know to just spray the rubber isolators again with the silicon spray and it's good to go.

 

Good for you!

 

Hey just wanted to thank you for posting this. My C400 front suspension was squeaking like a newlywed couple's old mattress.
I went to town on all those rubber bushings with the grease gun, and after a couple days of driving, not a squeak to be heard! Crossing fingers it holds up during the colder season.