Broken Rear Radius Rods?

DoubleA98391 · #1 07-10-2018, 01:30 AM

Hi everyone, this is my first post here but not my first visit. Usually I can find a post that will detail a problem I am having but I can't seem to find anything on this issue.

I recently had to replace the rear airbags in my 2009 X5 35D, and took it to a mechanic to have the suspension calibrated after I got the job done (not sure why it needed it but it was done). After that visit I started hearing a clunking noise in the rear when going over bumps at low speed. I looked this up and people said it could have been the sway bar end links, however these parts on my car are tight.

So my questions are can these broken parts be the source of this clunking noise? What do the rear radius arms do and is the part shown in my photos the radius arm? How could something like this break? Both sides have the same broken part in the same way.

Thanks for any help,
Aaron

Sponsored Links

LightlyToasted · #2 07-10-2018, 08:35 AM

I suspect those are the radius arms; possible to take another pic with more in the picture?

By any chance, do you experience any side to side shimmy / sway / looseness from the rear?

DoubleA98391 · #3 07-10-2018, 01:43 PM

I don't feel any looseness while driving. Not that I can tell at least. Everything feels fine as far as drivability, I just hear the clunking noise. I would record it but I'm in the middle of removing CBU from my intake so it will be a little while before it's running again.

I've included wider angle pictures of both sides.

LightlyToasted · #4 07-10-2018, 02:18 PM

OK, yes, those are (were?) the radius arms. I'm not sure of their specific purpose, but learned long ago that once one part of a suspension system is weak or broken, the additional stress causes other parts in the system to get weak or fail.

I'm not sure if missing radius arms would cause clunking, but a worn ball joint or bushing or end link or rear shock mount can. Pry or squeeze (with large channel lock pliers) all of the ones that you can see. If the noise is easily reproduced by bouncing the vehicle around in your garage, it helps a lot to have it up on ramps and have a helper bounce it while you look underneath at what is moving excessively.

I'll be going through a similar process to locate the source of rear end sway on mine. I can actually push on the rear quarter panel and the vehicle will oscillate side to side.

DoubleA98391 · #5 07-10-2018, 02:25 PM

I will have to try this. Everything seems tight with the tires in the air but that isn't how it drives down the road. I'm just curious about how they broke in the first place. They are up out of the way of debris from the road. But maybe since they're cast aluminum a big pothole could do the job?

LightlyToasted · #6 07-10-2018, 03:02 PM

Quote:

Originally Posted by DoubleA98391

I will have to try this. Everything seems tight with the tires in the air but that isn't how it drives down the road. I'm just curious about how they broke in the first place. They are up out of the way of debris from the road. But maybe since they're cast aluminum a big pothole could do the job?

Maybe, but that wouldn't be my guess. I'd suspect metal fatigue, possibly from something else being worn and causing excess movement and additional stress on that part. I have some experience with metal fatigue issues in the rear end of E36 and E46 chassis cars. It's interesting though that yours are broken on both ends; I'd expect metal fatigue would break one side and the other side would dangle. I'd be interested in hearing from others who've had this problem. I'll check mine tonight. I'm actually hopeful that this is it, as it looks straightforward to replace.

LightlyToasted · #7 07-10-2018, 09:39 PM

Mine are OK. Will check ball joints and bushings this weekend.

DoubleA98391 · #8 07-10-2018, 09:46 PM

Can you take a photo of yours? I'd like to see what they're supposed to look like if it's not a hassle. And just to clarify, the suspension needs weight on it to test the ball joints, bushings and so on right? Unfortunately I don't have a helper to bounce the car like you said. I'm not sure if I even need to test since this problem just started about a week ago and everything feels like it did when I got the car. I might just replace the rods and then see if the noise is gone.

Thanks for the help so far.

LightlyToasted · #9 07-10-2018, 10:02 PM

Quote:

Originally Posted by DoubleA98391

Can you take a photo of yours? I'd like to see what they're supposed to look like if it's not a hassle. And just to clarify, the suspension needs weight on it to test the ball joints, bushings and so on right? Unfortunately I don't have a helper to bounce the car like you said. I'm not sure if I even need to test since this problem just started about a week ago and everything feels like it did when I got the car. I might just replace the rods and then see if the noise is gone.

Thanks for the help so far.

I'll snap a photo this weekend when I have it up on jack stands. In my limited experience sometimes the suspension needs to be loaded to make play more obvious, sometimes not. I've even replaced sway bar end links which I swear weren't budging with giant channel locks only to have a clunk go away.

If I were you I would definitely replace the radius arms first (looks easy) to see if the clunk goes away.

Toothbrush · #10 07-11-2018, 09:23 AM

Not sure of the history of this vehicle, but was it taken off road with heavy use (rock climbing), involved in some sort of collision, dropped from a lift...?

For both sides to be broken at the same point suggests something more than a pothole, unless it was the width of the entire vehicle + sufficient speed. At least to me.

Sponsored Links