1985 300D Front Driver's popping/ knocking
 

I've searched to the point of exhaustion and pained eyes. I've found similar stories but nothing spot on that I could find.

1985 300D, entire front end is new with the exception of the firewall area sway bar bushings. Engine mounts are 1 year old, everything else about 4 months.

I get a popping/knocking sound predominately when turning the car at low to mid-range speed (10-30MPH), when the weight of the car settles to either side. I also hear/feel it when hitting the brakes hard. No noise when just going over speed bumps or rough roads. I think I can also hear it when I shut down the engine as well. Engine shocks are also new (about 3 weeks old).

I've checked the rotors and calipers, they're all new and tight in the front. I've tried rocking the engine on the mounts to duplicate the sound but haven't been able to. My indy shop went through it and couldn't quite tell but thinks it could be a guide rod mount. My alignment shop went through it and thinks they've narrowed it to the UCA bolt using their stethoscope tools. Nothing is loose.

I'm stumped. I tried getting a video this morning. It's not the clearest audio, but the noise can be heard at 0:54-55, 1:10-12, 1:25, 1:51, 2:00, and 2:08.

https://www.youtube.com/watch?v=juJNv24gHRg&feature=youtu.be

My question is, where the suspension parts genuine Mercedes/Lemforder or lesser quality Chinese parts.

Guide rod mounts and UCAs were all Lemf.....(however it's spelled). I think the only URO part I used was for the bushing at the bottom of the LCA under the spring mount.

If the top of the shock absorbers are not screwd all the way down or the rubber bushings are shot they will also pop when they move

I have this problem too. I eagerly await a solution. Everything in my front end was replaced in the last two years. Mine sounds like somebody is striking my spring with a mallet. W126 tho. Happens while braking and turning...almost like a balljoint. Perhaps I damaged my new joint while installing it. Or perhaps it is a noisy shock that binds. Or my cheep Meyle spring pad.

Dunno. I’m going to keep driving.

If you used a generic press, damage during installation as all but guaranteed.

A lot of members including myself have use the generic C-press to install the Ball Joints on the Steering Knuckle. However, that of course does not mean everyone will have succes.

You do need to get some wet/dry sand paper and clean out the bore on the Steering knuckle. You can heat the steering knucle to expand the hole.
You can put Oil on the end of the Ball Joint that goes into the steering knuckle. (I was taught not to press things together dry unless some spec called for that.)

In the attached pic is a read arrow. I should have taken the time to get a large Washer and ground out the inside diameter so it would slide over the ball joint shaft without touching because with the rounded top of the Lemforder ball joint the Press wants to slide off to one side. With the Washer there would have been a nice flat surface for that.


For others:
http://www.peachparts.com/shopforum/diesel-discussion/275392-ball-joints-differances-tolerances-123-a.html

This is a pic of a tool I tried to make with for the C-press so it would push on the lip of the Lemforder Ball Joints. I gave on it before I finished it. In the pic it needed to be much shorter and have a step on the opposite end that fit into the C-press would have been helpful.

The tool needed to be cut long the dotted line to shorten it. That is a tube welded to a Washer. In order to get the right ID of tube I had to cut the tube length wise, pinch tube together and weld the length of the cut together. I could find no tube locally that with a good inside diameter that matched.

Even more helpful would have been if I read the old thread because another member, Dormison had already made the same tool.

Another problem with the C-press (I have 2 from different makers and also used a free rental from Autozon just to see the differences) is that the thread rod and hole have a very sloppy fit to them and there is a good deal of wobble. That makes it harder to press straight in.

Yep, that would make sense. My issue started after I started throwing parts at the front end. I took the knuckles to a shop and they used a generic c frame press and an air tool to put in the ball joints. It really sounds like a ridge worn on the balljoint that clunks in a certain vertical and rotational position during turning at low speeds. I don’t think I’ll be redoing that job anytime soon.

no Worries. Time to drive the car.

I had creaky sway bar isolators, clunky guide rods and loose tie rods. Funny, I went in and changed all kinds of stuff and the sounds changed but this last clunk didn’t go away. It reminds me of my worn joint in my 240d that would clunk as I pulled up into my driveway or went slowly over a speed bump. But this one on the SD clunks as I said when I turn sharply in a parking lot. I bet I could change things up by marking the joint relative the the knuckle, undoing it, then rotating it 180. degrees and retorquing.

That would put the theoretical burr in there at a different spot. Probably it would clunk when I did something else like turned the other way. Maybe when I’m really bored I’ll try this experiment. But as I said, I gave up worrying about it.

If the Ball Joint is actually loose due to damage then you ought to see movement when you follow the procedure to check that.

Mine isn’t worn. There is no vertical play. What I suspect is there is a burr that hangs up in there while doing certain maneuvers.

Did you change out the Guide Rod Bearing Mount when "throwing" parts at the front end? My experience of popping turned out to be these mounts.

I solved my popping problem
 

So I posted here and I’d had this popping problem in parking lots when making a sharp turn. It came from the drivers side.

Well on a whim I jacked up the car this morning and slipped a 22mm box wrench around the lower balljoint nut and ...it turned a 1/4 turn!

So I torqued it up as much as I could without splitting the upper joint and removing the caliper. The sound is gone.

Just thought that might help someone.

Perhaps when I was in there last I didn’t get it tight enough. It is hard to access and as I recall it wants to spin unless you load the car which is hard with everything open for access. Or maybe it just worked loose.

Love simple solutions.

When I needed to make an adapter to press w123 ball joints, I found that a threaded coupler for 1.5” schedule 40 pipe could be made to fit by taking a die grinder to the threads on the inside of one end. I ended up welding mine to a heavy plate with a notch cut in it and using an H frame press and they went in easily.

X2 on double checking the guide rod mounts for the noise though.