What "knocks" in the front end?
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
What "knocks" in the front end?
I put a new end link on as I was getting that familiar "knocking" sound over bumps. I'm still getting the noise, though? Best I can tell (by hand) everything seems tight under there. There's really not much else under there, either, given the air suspension. What else could make that light knocking sound? Am I missing something? I guess I could have gotten a bad end link. Maybe I should swap left for right.
Senior Member
Joined: Oct 2019
Posts: 277
Likes: 73
From: Perth Australia
12 C200, 12 C180, 10 Fuso Warrior crew cab, 08 RTV ute, 05 Smart Fortwo cabrio, 09 Smart Fortwo
Just read a thread before that said they solved a front end knock with some new swaybar bushes
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
I would never have guessed that a bushing would give that same knocking sound. Interesting. Did they say it was a similar sound to an end link?
Senior Member
Joined: Oct 2019
Posts: 277
Likes: 73
From: Perth Australia
12 C200, 12 C180, 10 Fuso Warrior crew cab, 08 RTV ute, 05 Smart Fortwo cabrio, 09 Smart Fortwo
Cant remember what thread it was in, sway bar bushes are hard to diagnose though with tension on the sway bar
MBWorld Fanatic!
Joined: Jan 2010
Posts: 3,132
Likes: 792
NGL450 w/EORP, S550
Sway bar end links. Easily diagnosed by disconnecting them on the bar side and driving slowly over a few bumps. If the bar has a croak or grind when you move it manually the bushings could be suspect, but 9/10 the end link ball joints are the culprit.
Replace both at the same time with an OEM brand - otherwise the clunk will be back in short order.
Replace both at the same time with an OEM brand - otherwise the clunk will be back in short order.
Last edited by Max Blast; Dec 6, 2019 at 11:28 AM.
MBWorld Fanatic!
Joined: Jan 2010
Posts: 3,132
Likes: 792
NGL450 w/EORP, S550
I put a new end link on as I was getting that familiar "knocking" sound over bumps. I'm still getting the noise, though? Best I can tell (by hand) everything seems tight under there. There's really not much else under there, either, given the air suspension. What else could make that light knocking sound? Am I missing something? I guess I could have gotten a bad end link. Maybe I should swap left for right.
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
Well that makes sense - probably best to disconnect both end links as that eliminates the end link and the sway bar from the equation, helping to narrow down the possibilities. I'll just make sure to stay away from the "twisties" when driving!
I've heard that before - about replacing both. But I wonder if this is more "theory" or something that would only be seen in lab-type situations? I mean, the "wear" we're talking about is measured in the thousandths of inches - and there's just too many other places for that miniscule amount to be taken up/lost from right to left. Just wondering outloud on that...
I've heard that before - about replacing both. But I wonder if this is more "theory" or something that would only be seen in lab-type situations? I mean, the "wear" we're talking about is measured in the thousandths of inches - and there's just too many other places for that miniscule amount to be taken up/lost from right to left. Just wondering outloud on that...
Trending Topics
Member
Joined: Dec 2018
Posts: 247
Likes: 59
From: Lawrence, Kansas
GL320
Well that makes sense - probably best to disconnect both end links as that eliminates the end link and the sway bar from the equation, helping to narrow down the possibilities. I'll just make sure to stay away from the "twisties" when driving!
I've heard that before - about replacing both. But I wonder if this is more "theory" or something that would only be seen in lab-type situations? I mean, the "wear" we're talking about is measured in the thousandths of inches - and there's just too many other places for that miniscule amount to be taken up/lost from right to left. Just wondering outloud on that...
I've heard that before - about replacing both. But I wonder if this is more "theory" or something that would only be seen in lab-type situations? I mean, the "wear" we're talking about is measured in the thousandths of inches - and there's just too many other places for that miniscule amount to be taken up/lost from right to left. Just wondering outloud on that...
MB World Stories
The Best of Mercedes & AMG
8 Oddball Mercedes Ideas That Actually Made it to Production
Verdad Gallardo
Dubai Tuner Gives the Mercedes G-Class An Entirely New Look
Verdad Gallardo
Six Gift Ideas Your AMG Loving Dad or Grad Will Cherish
7 Craziest Things AMG Gas Ever Built
Verdad Gallardo
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know
Verdad Gallardo
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,787
Likes: 646
From: Emmett, ID, USA
2007 GL450
It's a mystery to me why these things have such an insufferably short lifetime. I'm guessing it has to do with installing them with the suspension deflected, so they are pre-loaded or pre-stressed when you lower the front end back down. Something like that.
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,787
Likes: 646
From: Emmett, ID, USA
2007 GL450
Well that makes sense - probably best to disconnect both end links as that eliminates the end link and the sway bar from the equation, helping to narrow down the possibilities. I'll just make sure to stay away from the "twisties" when driving!
I've heard that before - about replacing both. But I wonder if this is more "theory" or something that would only be seen in lab-type situations? I mean, the "wear" we're talking about is measured in the thousandths of inches - and there's just too many other places for that miniscule amount to be taken up/lost from right to left. Just wondering outloud on that...
I've heard that before - about replacing both. But I wonder if this is more "theory" or something that would only be seen in lab-type situations? I mean, the "wear" we're talking about is measured in the thousandths of inches - and there's just too many other places for that miniscule amount to be taken up/lost from right to left. Just wondering outloud on that...
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
I don't understand why they go so fast, either. Larger vehicles than this don't have the failure rate these do. Maybe the front end is just tightened down so much - for better handling - that they just can't survive. It does handle quite while for it's size. But, then, couldn't the end links be built "tougher"?
I'm not convinced on the "need" to be replaced in pairs, either? Plenty of info out there to support both thoughts, though. But these aren't a highly engineered product where they are that sensitive - in my opinion, anyways.
But, I just checked and I got 27K miles on the port side (where the knocking is coming from) and the starboard side is at 25K miles. If I determine that the problem is definitely a new/defective end link , I'll probably just go ahead replace the other side, too. Can't put the old one back on - had to rip the boot to hold the stud with pliers to get the nut off.
I'm not convinced on the "need" to be replaced in pairs, either? Plenty of info out there to support both thoughts, though. But these aren't a highly engineered product where they are that sensitive - in my opinion, anyways.
But, I just checked and I got 27K miles on the port side (where the knocking is coming from) and the starboard side is at 25K miles. If I determine that the problem is definitely a new/defective end link , I'll probably just go ahead replace the other side, too. Can't put the old one back on - had to rip the boot to hold the stud with pliers to get the nut off.
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,787
Likes: 646
From: Emmett, ID, USA
2007 GL450
MBWorld Fanatic!
Joined: Jan 2010
Posts: 3,132
Likes: 792
NGL450 w/EORP, S550
I'm gonna call BS on that one. That doesn't make any sense, short of the new link putting some sort of pre-load stress on the old one. The lesson then would be you need to loosen the side you don't replace, effectively reinstalling it.
It's a mystery to me why these things have such an insufferably short lifetime. I'm guessing it has to do with installing them with the suspension deflected, so they are pre-loaded or pre-stressed when you lower the front end back down. Something like that.
It's a mystery to me why these things have such an insufferably short lifetime. I'm guessing it has to do with installing them with the suspension deflected, so they are pre-loaded or pre-stressed when you lower the front end back down. Something like that.
wrt to life span of brands, I’ve had cheap chinesium parts last a week. Not doing that again.
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
It had a hole in the end of the stud for an allen wrench. Which would be fine if the nut wasn't so dang hard to remove. But the allen hole was starting to strip out.
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,787
Likes: 646
From: Emmett, ID, USA
2007 GL450
i think he’s talking about internal ball and socket wear - which is also my point. Unless these joints wear evenly, the side with the largest clearances will wear at a faster pace than the side with tighter clearances. That is assuming that loads are evenly distributed.
wrt to life span of brands, I’ve had cheap chinesium parts last a week. Not doing that again.
wrt to life span of brands, I’ve had cheap chinesium parts last a week. Not doing that again.
I put in Febest. Got like a month out of one side. OEM, I got 20k miles. The ones I currently have on the shelf are Lemforder. I'm living with clunkety clunk because I can't bring myself to install something and wait for it to start clunking again.
Member
Joined: Dec 2018
Posts: 247
Likes: 59
From: Lawrence, Kansas
GL320
Yeah, I guess. Maybe I'm slow, but still - I don't see why a worn socket will wear faster than a tight one. In fact, I'd think it would be the other way around.
I put in Febest. Got like a month out of one side. OEM, I got 20k miles. The ones I currently have on the shelf are Lemforder. I'm living with clunkety clunk because I can't bring myself to install something and wait for it to start clunking again.
I put in Febest. Got like a month out of one side. OEM, I got 20k miles. The ones I currently have on the shelf are Lemforder. I'm living with clunkety clunk because I can't bring myself to install something and wait for it to start clunking again.
Any chance the wrong length links were installed? There are long ones and short ones.
Member
Joined: Dec 2018
Posts: 247
Likes: 59
From: Lawrence, Kansas
GL320
The sway links and bar are to be considered a single mechanism in how it is designed to work. Of which, it depends on ALL components having a similar strength because wear from stress will take the path of least resistance. Its the same reasoning behind replacing springs or shocks on both sides when one side fails.
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
No luck. Disconnected the driver's side sway bar and the same sound was still there while driving around. Anti-sway bar bushings look very good - couldn't get any sound out of them by hand or by using a pry bar. HOWEVER, while I was putting it back on, and had the front end in the air, I stated pushing/pulling/racking the wheels. I found that the driver's side wheel, when grasping the wheel horizontally and pushing/pulling (basically trying to quickly "steer" the wheel back and forth) there was a very similar sound. Looking closer, the sound is coming from inside the steering rack - where the steering tie rod connects to the rack. There's also a small power steering fluid leak/seep.
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,787
Likes: 646
From: Emmett, ID, USA
2007 GL450
I'd like to think I would have noticed a length difference! But I can be pretty retarded sometimes. I'll have to put in the Lemforders to see how they hold up. I'm inclined to install them with everything straight and level in the front end. That's about the only thing I can think I did "wrong".
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,787
Likes: 646
From: Emmett, ID, USA
2007 GL450
No luck. Disconnected the driver's side sway bar and the same sound was still there while driving around. Anti-sway bar bushings look very good - couldn't get any sound out of them by hand or by using a pry bar. HOWEVER, while I was putting it back on, and had the front end in the air, I stated pushing/pulling/racking the wheels. I found that the driver's side wheel, when grasping the wheel horizontally and pushing/pulling (basically trying to quickly "steer" the wheel back and forth) there was a very similar sound. Looking closer, the sound is coming from inside the steering rack - where the steering tie rod connects to the rack. There's also a small power steering fluid leak/seep.
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
MBWorld Fanatic!
Joined: Jan 2010
Posts: 3,132
Likes: 792
NGL450 w/EORP, S550
No luck. Disconnected the driver's side sway bar and the same sound was still there while driving around. Anti-sway bar bushings look very good - couldn't get any sound out of them by hand or by using a pry bar. HOWEVER, while I was putting it back on, and had the front end in the air, I stated pushing/pulling/racking the wheels. I found that the driver's side wheel, when grasping the wheel horizontally and pushing/pulling (basically trying to quickly "steer" the wheel back and forth) there was a very similar sound. Looking closer, the sound is coming from inside the steering rack - where the steering tie rod connects to the rack. There's also a small power steering fluid leak/seep.
that one usually eats pumps but might have been severe or prolonged enough to cause steering rack damage. Just thinking out of the box here...that $3.50 o-ring hardens up and fluid leaks out, owner keeps pouring in more and the steering system components decay over time.
Thread Starter
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
do you now or have you ever had the ever present power steering reservoir fluid leak?
that one usually eats pumps but might have been severe or prolonged enough to cause steering rack damage. Just thinking out of the box here...that $3.50 o-ring hardens up and fluid leaks out, owner keeps pouring in more and the steering system components decay over time.
that one usually eats pumps but might have been severe or prolonged enough to cause steering rack damage. Just thinking out of the box here...that $3.50 o-ring hardens up and fluid leaks out, owner keeps pouring in more and the steering system components decay over time.
Member
Joined: Dec 2018
Posts: 247
Likes: 59
From: Lawrence, Kansas
GL320
Mine was leaking from where the high pressure hoses attach to the rack but it looked like it was leaking from the drivers side tie rod boot. Replaced two green o-rings and it went away.
