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clunk/rattle in rear end over bumps

43K views 30 replies 13 participants last post by  Striker17 
#1 ·
My 2005 with 50k has had this noise for probably 10-20k now.

When going over pot holes or sharp bumps or speed bumps, it makes this loud clunk/rattle like something big is loose in the back end.

I removed all items from the trunk and checked the spare area and everything is tight.

I took it to the dealer and they said everything is tight.

I saw several threads on this but no answers yet.

Anyone find a solution? Anyone having the same issue?

Thanks.
 
#6 ·
I get this same sound at around 40k miles... loose endlink you say?

Many people have gotten similar sounds from blown out shocks as well... either way i'm planning on replacing my whole front and rear suspension

Anyone have a definitive answer on this?
 
#8 ·
hmm, well i'll check it this weekend and find out if its the same on mine
 
#9 ·
One way to fix the bolts from coming loose is to put washers between them and the endlinks. I use to have a gocart with a roll cage and those bolts use to get loose all hte time so i finally put washers inbetween the nut and the cage and it never got loose again. I think this might work the same. I'm gonna try it as i have the noise as well.
 
#10 ·
Mine had a really annoying rattle in the back after I installed Koni Yellows (shocks).

I don't own a torque wrench so I can't give you good numbers, but I tightened the ever living crap out of the lower mounting bolts and it fixed it. The shocks were moving and rattling on the bolts on the lower control arms.

-Eric
 
#11 ·
Well i went ahead and tightened everything. One of my endlink bolts was loose. That took care of the squeak but there's still a clunk. I think rccardude might be right. Ima check my shock bolts at some point. That might be it.
 
#12 ·
The OEM endlink nuts are the slightly oval type of lock nut. They're really only good for 1 tighten. If tightened back to the OEM torque value (40ft-lbs) they'll likely loosen up again. A drop of blue thread locker goes a long way though. (The nuts are quite re-usable in this manner)
You can usually get new nuts from the dealer pretty cheap.

Beyond the nuts, eventually the ball joints within the links just wear out. This results in the same clunking, no matter what you do to the nuts. I got 70k out of mine.
 
#13 ·
I just don't understand what would be causing a clunk from that ball joint though.
 
#14 ·
Same problem here. very annoying. Although i know that all my 4 shocks need to be replaced, i still think its the end links, either way im planning on getting an after market sway bar and will probably try and take care of it when installing this mod.
 
#15 ·
I have brand new koni fsd shocks, an eibach prokit, an aftermarket sway bar, and i still have the thumping. I ordered some mazdaspeed end links and going to replace them and see if that works. I'll let you all know.
 
#16 ·
Over time the ball wears in a little bit and the socket wears out a little bit. You end up with some wobble and play. All that is in there for lube is the little dab of silicone the robot applied at the factory.

The mazdaspeed3's OEM endlinks are much more substantial. They retain the regular 3s upper joint and iirc 10mm stud, but the lower joint is much larger and has a 12mm-ish stud. You may need to bore out the sway bar holes.
 
#18 ·
Thanks for the info c_thur. We'll see about the modifications to the bar.
 
#19 ·
I had looked on the forum earlier in the year but failed to find some of these older posts -- my '06 GT 5-door with ~58K miles has the same sounds, like a loose tool box rattle every time we go over RR tracks or bumps -- sounds like junk in the trunk but did the same and took everything out without success. I even had my regular mechanic put it on a 'shaker' machine and could hear it but could not figure out what was causing it -- have a Mazda dealer appt. for 10/31. I had also thought that there might be a TSB on this? In any case looks like I should mention 'sway bar end links' or 'trailing arm bushings' is that about correct? I'm planning on trading or selling this car next month and need to get this resolved as it makes it sound like a piece of junk over anything other than a glass smooth road! For those who have fixed this, how long does this tightening up work -- a few thousand or less or worse than that? My wife is normally driving this car as I take my old trustworthy Miata most of the time and it doesn't bother her but boy I notice it right away and don't get me started on the tire noise (Bridgestone Grid's 019's -- decent traction but very noisy after 20K miles) --- hard to believe an open roadster like the Miata could have less road noise than a closed hatch but it does!
 
#20 ·
After replacing the sway bar endlinks i finally have realized what the noise is coming from. It was not the endlinks but the spacers holding the sway bar to the frame of the car. There is a lot of play allowing the bar to move up and down in the bracket. I need spacers that are super snug in order to keep the sway bar from bouncing around in the bracket. This is what is causing my clunking noise. I was thinking about filling the inside of the spacer with something to make the fit around the sway bar more snug. Anyone have any suggestions. I don't remember the thickness/brand of my aftermarket sway which also sucks. I need some recommendations but i'm 99% sure this is where my noise is coming from.
 
#21 ·
Is your aftermarket bar using the stock brackets or did it come with some? That might influence a bushing purchase, but I used the bushings from a racing beat bar with both the OEM and some aftermarket brackets - both just required some coaxing to get in there.

If the bar is loose within the bracket, measure the bar with some calipers, to get the size. There are some makers of aftermarket urethane bushings. Lube them up well with grease.

If the bushing is loose against the car, try and put some cork or rubber sheets/layers in there.
 
#22 ·
Bar is loose in the bushing. I don't have a measuring caliper. Is it diameter or circum. I have plenty of lube on there. I can remember if they are aftermarket brackets or not. Bracket and bushing work well together it's like the bushing isn't thick enough.
 
#24 ·
Good call. I think it's an h&r at 26mm
 
#25 ·
After replacing endlinks, sway bar bushings, i finally narrowed it down to the bolts holding the shock in place at its base. Went ahead and impacted it tight.
 
#26 ·
[quote author=joel1618 link=topic=109827.msg4141284#msg4141284 date=1320287742]
After replacing endlinks, sway bar bushings, i finally narrowed it down to the bolts holding the shock in place at its base. Went ahead and impacted it tight.
[/quote]

So are you saying that it was not the sway bar at all? Just the top mounts of the shocks?
 
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