Knuckle Cracking Sound From Front End
 

Just the other day I noticed a knuckle cracking sound coming from the front end of my 1992 W124 300TE 4Matic wagon. I can't tell if it's coming from the wheels or under the engine, but it is definitely connected to the turning of the wheels. I only seem to hear it at low speeds, it happens in both forward and reverse, but not all the time - it seems to come and go. Often, the wheel needs to make a full revolution from a full stop before the noise arises, but not always. This evening I didn't hear it at all on the drive home until I pulled into the garage. The wagon has almost 140,000 miles on it. Around 105,000, the left & right front axle and inner CV joint boots were replaced, but as long as I've owned the car, (approx. since 95,000), I have never replaced the front wheel bearings or tie rod bushing. I did a search here and found nothing, other than it doesn't sound like the noise of a bad bearing. Any thoughts? I'm stumped.

1962 MB 220SEb "Fintail" Sedan
1992 MB 300TE 4Matic Wagon
1995 Subaru Wagon AWD

If its a groaning creaking sound at the end of the steering revolution then it could be the tie rods. Mine looked good from the outside but the grease inside the outside ends were gone.

KNUCKLE SOUND
 

I have a w126 and I get that same similar sound when the ball joints are going out. Due to design, water seems to get into the metal joint and causes over time to rust. Then you get that sound. I would have them checked as a start.

2nd the balljoints as a possible culprit.

Are they the originals? Probably about due.

As far as I know, the ball joints are the originals. That is, they have never been replaced as long as I've owned the car, which is over four years and 45,000 miles.
So how difficult is it to replace the ball joints? Is it a DIY job, or are a press and special tools needed? Also, if it is a DIY job, what else should be replaced, for preventative reasons, while I'm in there?

I had a similar sound on a 93 300E and it came from the rubber suspension bushings. A little WD40 sprayed on the bottom suspension bushings and it was good for another couple of months. Sometimes it sounded like the front end would fall out but really a nothing. Although I guess it could happen at other times, it did seem more pronounced when you were turning. Maybe you will be lucky and find it is a cheap, simple thing. No, I doubt that will happen if you have my luck!

Assuming your 4matic is similar up front...

You can get by with a decent vise and a big hammer instead of a press. The hard part is getting out the spring. Everyone will tell you you need the $600+ special tool, but I have been able to improvise with more standard spring compressors. I have done 3 of these jobs now. There is a lot of discussion in the archives on this.

When doing the balljoints, I suggest replacing the control arm bushings. No point is having to remove the spring again any time soon. Not so compelling, but it's also a good time for swaybar bushings, strut replacement,...