Clunk in front end
 

Yesterday while pulling into a parking spot I heard a clunch come from the front end when I turned the steering wheel straight. I looked at my wife as if to say "what the hell was that?" when she said "did you hear that?" I turne dhte wheen back and forth a few times and it clunked every time it changed direction. What do I look for? It this usually something serious?

I think I may have hert the cars feelings. Not more than 10 minutes before I saw a Jetta TDI Wagon and told my wife how much I wish we could find one at a resonable price b/c it's time for her to have a new (to us) car.

thanks
C

My first guess based on your description would be guide rods.

I agree.

Most that I repair are the upper (alloy) arms with the ball joint and roll bar mounting hole.
The next most common is the lower ball joint(s)......both these items make a loud 'crack' when vehicle is high sided on opposite corners....like a ramp or driveway.


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Thanks. I have absolutly zero experiance w/ Mercedes front end work. Any pictures or good descritions of what to look for? How will I recognize the problem when I see it? I hope it's pretty obvious.

You have an important clue in that it started all at once. Start by having someone turn steering wheel back and forth with you listening and looking at suspension of car on your hands and knees. That may localize problem fast. If that does not locate it jack front end of car up and start prying and looking and listening for the source of noise or slackness in something causing it.

Here is a good starter link to get you up to speed. CLICK

Front end work is not an average DIY project, other than shocks the rest gets pretty involved, most times you need a lift.
The only way to check the front end (IMO) is to get car up on rack and with large crow bar or similar check all joints for excessive play, and with large plyers check ball joints for play.
Don't mess with the springs, if they get loose they will go through anything in their path

could a bad uca cause a clunk? Bit seems that is what I have... How would one best determine which is the culprit?

What are the conditions when you hear the clunk? Turns, uneven pavement, low speed, high speed, or coming to a hard stop.

The upper control arm is fairly straight forward to inspect. If the bolt appears to be centered in the bushing, front and back, then it should be fine. If it appears off-centered, then it likely needs replacement.

I generally get the clunk when turning the wheel in conditions where the road and thus wheel height changes... Something like pulling up into a driveway apron or things like that. Sometimes speedbumps do it to. That said it is very intermittent. From my other thread, it seems most think my UCA is letting my DS wheel go out too much on the top...

I would think an upper control arm problem would show up as some pretty severe tire wear.

If this isn't the case, maybe the sway bar bushings are worn. Although not common, I have read here about worn shocks causing strange sounds. Without tire wear, I would think along the lines of the absorbtion side of the suspension.

UCA and tie rods wear out the front tires really fast. Look at the rubber around the UCA if it is cracked and loose, then they are bad. My UCA and tie rods were so bad you could hear like a metal on metal sound...but NOT a clunk. The steering will be wonky too..hard to control
I have read that if the sound you are hearing comes from the drivers floorboard or a thumping near your left foot it could be the guide rods

Some pics of my situation are here:

http://www.peachparts.com/shopforum/diesel-discussion/293431-suspension-diagnosis-w123.html

DS tire tilts way out and rubs the guide rod at some point of travel.

My clunk is opposite side - passenger side.

I had a bad LCA bushing, was wearing that tire real bad. Swapped itvout, still have tire wear, both sides, outer edge. Have pics of that someplace...

Your alignment is waay out of whack...
You should be able to go to a tire place and get a free diagnosis
Ask for an alignment or let them know you want to have one eventually, but need to resolve the "leaned tire"
They can tell you what pieces and parts are worn out or broken
Most tire places will not even do an alignment if the parts are too worn out
That would be a good place to start


All of the front end parts and pieces need to be in good condition to be able to do an alignment properly
UCA LCA tie rods center drag link and maybe ball joints...get the tire place to explain this stuff to you while it is on the lift.

Some of the "tests" need to be performed on the ground w/ one wheel off the ground and one wheel lifted. This will give you the amount of "play" in the wheel being tested.
I am not a mechanic, but this is my experience w/ my car
You can also search here in the forum for "caster and camber" or "front end" and or alignment...lots of reading.

WHunter has plenty of links to read all about front end stuff
Check the resources and diy links