I just picked this up for a steal of a deal (or so i thought) I am not even all the way home yet when the rear suspension starts making a very loud and noticable squeaky noise from the rear suspension. Right now I am sick and cannot dig into the issue I an very busy this week, if anyone has experienced this or knows what it could be please let me know.

https://youtube.com/shorts/TkEklPg2YB8?si=2niu7UNY-wtpBTKu

https://youtube.com/shorts/cGli8tIGGEk?si=_8g8wk1x4JpJ9dM1

 

Your link doesn’t work on my iPhone , the small 6” rear link bushings go bad. And shocks and springs break , bearings etc etc go bad. Take it somewhere and have someone look at it

 

Wow! That's annoying. Could be a lot of things. At that age I'd guess shock absorber if not yet replaced. Put you head near the shock and have somebody bounce the car. A cheap harbor freight stethascope would help find the noise. Bilstein B4 at rockauto.com under $100 ea. Do both sides and the shock mounts.
Simple DIY when you're healthy and have time.

 

Must be an iPhone deficiency - why we left 👋

 

( I always remove the "?si=" parameter text from a URL )

My initial knee-jerk thought is "bad rubber" somewhere. My thinking is "really old rubber" (shock mount points or strut sorta mount points) ... aged bushings ... but it could be something else.

The best option would be to have another person pulling on the top rack (as you did), and you laying under the rear end ... then have them rock it while you locate the source of the noise. Or lay your phone on the ground pointing up at the suspension point at one rear wheel , in video mode, while you rock it.

Unfortunately, I've yet to remove a rear wheel (to do brakes, etc), so I'm unfamiliar with the suspension components. Maybe the previous owner sprayed lube on the bad rubber, knowing it is old 🙂

BTW, how many miles are on the GLK ??

 

I will jack it up and take the wheel off and see if anything is obviously worn, if not, ill go get the stethascope, just sucks i gotta do even more to the car than i am already doing, i am already doing front swaybar links, thermostat, brakes all around, all fluid flush, alternator, bank 1 sensor 2 o2 sensor, and engine mounts in the near future. I picked it up for around $1700 below its value though.

 

110k miles, its been taken care of at a dealer its entire life, then again it is 15 years old, tomorrow i will have the time to try to figure it out.

 

I did my rear shocks last year at around 100,000 miles. I did the front struts this year and found a broken spring.

 

My 1st thought is also “old rubber.” But it could also be metal to metal from a completely worn out bushing.
Here’s a suggestion from my years of keeping older cars going:
-Get an aerosol can of silicon spray lubricant that has the little straw that can be attached to the nozzle for pinpoint application.
-I think most people can slide under the rear of a GLK, so do that with the can in hand and rock the body to get the squeak or have someone outside do it.
-Spray the suspension link points one at a time until the noise stops. The one it stops on is obviously the source.
-Include all the suspension link bushings, top and bottom shock absorber mounts, and coil spring mounts. Maybe even start with the springs, because I don’t think they are flattened on the ends and sit in synthetic bushings.

 

Why are you doing the alternator ? If it’s not working right the Regulator is what goes bad , the brushes wear out. Mine lasted 80,000m regulators are about 100$ at Fcp and not much more work when removing the alternator.

 

I'll bet they create a new thread , if required , about the alternator 👍 (no impact on rear suspension noise).

 

I took it in because i thought the battery was dead (wouldnt start, but i heard a click), mechanic hooked it up where it showed the voltages and he said that it was the alternator not charging and basically the car was purely running off the battery. Im guessing by what you said the alternator is fine its just the regulator? Anyway I already ordered the alternator so you live you learn i guess, mechanic is a friend so he will be doing my thermostat, belt, and alternator for $350 labor.

 

Look at the bottom coil or two of the springs. They're notorious for breaking.

 

I tried to do it today, dont have the jack insert to do it, ordered it, should come tomorrow, in the meantime, i noticed alot of oil from alot of places, notibly, the rear, in the picture, the top right tube is the dipstick. this is in the rear passenger side of the engine bay

 

this is my spring

 

So the issue was the spring? Did you figure it out? Is it fixed? I have exactly the same problem and I am glad I have your video, as i was never able to capture the sound. Every time I drive to my mechanic it disappears. Thx!!

 

Congratulations on your new purchase! If it’s been decently looked after, it should provide you many more miles of driving pleasure.
Given the seemingly small amount of effort needed to make the squeak, I’m going to guess you have a cat stuck in the undercarriage 🤪
in my experience when rubber bushings get play or wear out, you hear loud thunk sounds over bumps, not squeaky sounds, but I have been wrong many, many times in life. A quick test to find the culprit here would be a shot of WD-40, Fluid Film or similar on rubber bushings (one at a time) and make note of the impact it has on the sound. A change in the sound (either reduction, pitch, or elimination) means “bad guy” found. Based on the sound in your video, I’m leaning more towards a metal on metal issue, possibly the spring. The same troubleshooting method can be used on the springs as well. This will NOT solve the squeaky problem, just help you find it. Any chance the car sat in high Florida water, like a flood? Salt water can wreak havoc on suspension parts.
Keep us updated, I’m sure others in the group here (myself included) will benefit.

 

I bought 2 rear new springs , it raised up the rear 3-4 “ , so I bought Used EBay mb Glk springs , it’s better . New rear springs messed up the front suspension and made it look like a joke. What a headache. The eBay dealer I used was very good , I can find the seller if needed . (I answered this 10 minutes ago I guess I didnt hit Send) 🤪