Tracking down a clunk from the rear

[duncan]

I’ve searched and I haven’t been able to find someone with this issue or a solution.

I’ve got a GenPu on a stock suspension.

I get a clunk from the rear when I go over bumps sometimes. It only happens at slower speeds (under 30mph).

It sounds like a low pitched rattle.

I’ve replaced my end links and rear shocks. Springs are in good shape. Rear wing is tight.

What else should I be looking at?

[Thor Hammer]

Originally Posted by duncan What else should I be looking at?

I know what I shouldn't be looking at...your disturbing avatar.

Anyhow, check your rear shocks/mounts and make sure the exhaust isn't hitting anything.

[jt080799]

I has similar noise at lower speeds or roads rougher than highwways. It turneed out to be the passenger new shock . the mount at top is new but the nut attaching it to the shock was not tight enough . tightened it up and noise is gone.

[duncan]

Originally Posted by Thor Hammer I know what I shouldn't be looking at...your disturbing avatar. Anyhow, check your rear shocks/mounts and make sure the exhaust isn't hitting anything.

I’ll check this out. It’s a stock exhaust, so unless something got bumped and came loose...

Originally Posted by jt080799 I has similar noise at lower speeds or roads rougher than highwways. It turneed out to be the passenger new shock . the mount at top is new but the nut attaching it to the shock was not tight enough . tightened it up and noise is gone.

Tightened the shit out of the top nut when I replaced my rear shocks.

[Solarsurge]

Originally Posted by duncan Tightened the shit out of the top nut when I replaced my rear shocks.

There is such a thing as torque specs. Suspension torque specs are CRITICAL, not optional. You absolutely WILL have noises, premature wear, failure, and constant outward cash flow for replacement parts if you don't follow these precisely.

[Thor Hammer]

Originally Posted by Solarsurge There is such a thing as torque specs. Suspension torque specs are CRITICAL, not optional. You absolutely WILL have noises, premature wear, failure, and constant outward cash flow for replacement parts if you don't follow these precisely.

That's a pretty bold statement. I get what you're saying and why but I wouldn't go so far to say stuff will fail if not followed perfectly. For some things the German torque spec of gutentight is ok!

Though for things like top strut nuts, ball joints, inner tie rods, and anywhere there is a suspension bushing I use factory torque settings as I don't want anything to come loose! Nor overtighten anything and damage it.

[Solarsurge]

Originally Posted by Thor Hammer That's a pretty bold statement. I get what you're saying and why but I wouldn't go so far to say stuff will fail if not followed perfectly. For some things the German torque spec of gutentight is ok! Though for things like top strut nuts, ball joints, inner tie rods, and anywhere there is a suspension bushing I use factory torque settings as I don't want anything to come loose! Nor overtighten anything and damage it.

People often forget that our cars are 3200 lb death machines and the suspension is what is keeping that object stabile and moving in the correct direction. Each and every part of that suspension works in harmony with the other parts to maintain control of your 3200 lb death machine while traveling at speeds in excess of 70 miles an hour. Overtightening one bolt can stress one part to a point of failure. Anything that has to do with the stability of a vehicle is a critical part. This is not a statement made for dramatic effect. It’s a statement made to keep people aware that it’s NEVER ok to eyeball it when safety is concerned.


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[duncan]

Alright. Let me rephrase. I tightened everything to as tight as it was prior to taking it off. Didn’t overtighten anything. Didn’t leave anything loose.

[cognus]

Noobie warning. I just got on this forum yesterday and my interests are about the Mazda 5, mine being a 2010 model, and I too have that rear end clunk, in addition to 3 or 4 in the front end. I could hear the rear one plain as day sitting in the middle seat a week ago. hear it and feel it. dunno what it is or even how to check. This thread tells me at least what all the parts are I need to check.

Aren't sway bar links a potential source of knocking and poor handling? I'm willing to go spend money on parts but when we had to replace suspension parts previously [twice, or thrice depending on how you count] it was a hunting expedition. Thankfully I have a great alignment/brake shop here that is willing to work hard to solve.

I'll keep listening

[Thor Hammer]

Originally Posted by cognus Noobie warning. I just got on this forum yesterday and my interests are about the Mazda 5, mine being a 2010 model, and I too have that rear end clunk, in addition to 3 or 4 in the front end. I could hear the rear one plain as day sitting in the middle seat a week ago. hear it and feel it. dunno what it is or even how to check. This thread tells me at least what all the parts are I need to check. Aren't sway bar links a potential source of knocking and poor handling? I'm willing to go spend money on parts but when we had to replace suspension parts previously [twice, or thrice depending on how you count] it was a hunting expedition. Thankfully I have a great alignment/brake shop here that is willing to work hard to solve. I'll keep listening

We don't do anything that's not a mazdaspeed on this forum. A mazdaspeed 3 or mazdaspeed 6? Yes, CX-7 with the turbocharged DISI motor? Yes.

A Mazda 5? No. Try another forum. But yeah, sway bar end links and bushings (when in need of lube) will go clunk.

Originally Posted by Solarsurge People often forget that our cars are 3200 lb death machines and the suspension is what is keeping that object stabile and moving in the correct direction. Each and every part of that suspension works in harmony with the other parts to maintain control of your 3200 lb death machine while traveling at speeds in excess of 70 miles an hour. Overtightening one bolt can stress one part to a point of failure. Anything that has to do with the stability of a vehicle is a critical part. This is not a statement made for dramatic effect. It’s a statement made to keep people aware that it’s NEVER ok to eyeball it when safety is concerned. Sent from my iPhone using Tapatalk

3200lb death machine! Well, my death machine hasn't killed me yet! But ok, follow all torque specs. Got it.

[Solarsurge]

Originally Posted by Thor Hammer 3200lb death machine! Well, my death machine hasn't killed me yet! But ok, follow all torque specs. Got it.

Haha, but it has the potential to any moment. Consider a broken ball joint. Imagine this in a Speed3 at 100+ MPH:
https://youtu.be/kHt8iKZcAxE


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[Thor Hammer]

Originally Posted by Solarsurge Haha, but it has the potential to any moment. Consider a broken ball joint. Imagine this in a Speed3 at 100+ MPH: https://youtu.be/kHt8iKZcAxE Sent from my iPhone using Tapatalk

Thank God we don't drive Dodges! Gnarly failure.

[5doorsoffury]

I had this problem once and it was driving me crazy. It turned out to be the end link attached to the sway bar was not tight enough.
I didn't have the hex key in the end link and I just tightened It Up by hand. Later on I went back put the hex key in the end of the bolt and tighten the nut.

I'm guessing your stock but you did say you replaced your end links so maybe you just didn't retighten them enough?