Resolving the Front end clunk (3 MPS Gen I)

So I seem to have finally beaten this on my car. I'll run through my journey briefly in the hope that someone else can benefit from the long frustrating experience...

Car was stock:
- No noise, until I blew a shock. This was resolved by replacing the shock under warranty. At this point the car was noise / rattle free. (roughly 3 years old / 40,000km)

Suspension modified:
- MazdaSpeed spring kit ( understand this to be a re-badged Eibach Pro Kit), Koni Yellow shocks added (front and rear)

Initially no noise, just an awesome handling improvement :afro: Noise develops over the coming 1000's of km. 3 particular noises:

1. A relatively quiet "slapping" noise happens at low speed when entering or exiting driveways. Noise traced to the Windscreen washer hoses not being properly located in their plastic retainers. Easily fixed.

2. An irritating rattle / multiple clucking noise when traversing anything but dead smooth road, seemingly from the LHS of the vehicle. Noise traced to cavitation sounds cause by a worn out and leaking Koni shock absorber. Shocks replaced (both left and right hand side), noise resolved.

3. A loose sounding clucking sound that came and went initially, but got progressively worse. It was accompanied by an increasingly unstable feel from the front of the car on hard cornering. Notably would be ok after having the car on a hoist, for tyre / brake changes etc. A large amount of work went into diagnosis / discovery of the cause including:

- Mazda looking at it under warranty, and believing to have fixed the problem. I believed it also, however it was indeed the above stated behaviour after having the car on a hoist.
- Tunehouse also fixing the issue. Same as above, and also told some body bolts were re-torqued. This actually did help for quite some time (3 months). I would be keen to hear what / where these bolts are.

- Sway bar bushes replaced. The stock bushed looked to be in perfect condition at the time of replacement, but the ~$20 price tag had me trying it as it was low impact on the wallet. No difference to the noise.

- End-links replaced (sometimes called sway-bar links). Ultimately, this has solved my issue. My OPINION as to why is actually to do with the joints themselves. I believe lowering the car, and therefore reducing the range of motion (vertically) that the wheel has, reduced that amount of movement that the joints experience. This affects there ability to self lubricate with the grease inside the joint. This theory explains why, after being on a hoist (where the suspension becomes fully extended) temporarily resolved the issue of the noise, as this allowed the joints to pick up grease again and therefore work properly.

Hope somebody finds that helpful :2thumb:

Note: I've also noticed a small handling improvement over the stock end-links. I ended up going with the Whiteline ones from GSL. They were adjusted to be the same length as the OEM as I'm not having any problems with the sway bar knocking on the sub-frame and I wanted to leave the sway bar with no pre-load. To quantify, I can now hold a corner speed some 15km's higher than previously before losing the front end on full acceleration. The entire front end now just feel "tighter"

Cheers,
--JC

Thanks for this info. I experience this on odd occasions coming out of driveways like you, and like you had Tune House re-torque some of the suspension which did seem to help! Will eventually get around to replacing the endlinks. How much were they to replace?

Technically, if your ride height is changed you shouldn't be using stock length end links,

Here is a quote from Nliiitend1 on MSF. He is the suspension guru.
"Actually, even though the measurement is the same as stock, lowering the car will indeed have an effect on the spatial relationship between the swaybar mounting collars and the endlink mounts on the struts.

As you change the ride height, the swaybar mounting ear on the strut stays in the same vertical position, while the subframe (and therefore the center of the swaybar, as it is mounted to the subframe via collars) will move vertically toward the ground.

With your setup (which uses OEM-location swaybar mounting tabs on fixed-length strut bodies), the lower the ride height, the longer your endlinks need to be to keep the swaybar in its "correct" orientation."

Quote:

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Originally Posted by Cton

Technically, if your ride height is changed you shouldn't be using stock length end links,

Here is a quote from Nliiitend1 on MSF. He is the suspension guru.
"Actually, even though the measurement is the same as stock, lowering the car will indeed have an effect on the spatial relationship between the swaybar mounting collars and the endlink mounts on the struts.

As you change the ride height, the swaybar mounting ear on the strut stays in the same vertical position, while the subframe (and therefore the center of the swaybar, as it is mounted to the subframe via collars) will move vertically toward the ground.

With your setup (which uses OEM-location swaybar mounting tabs on fixed-length strut bodies), the lower the ride height, the longer your endlinks need to be to keep the swaybar in its "correct" orientation."

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Yeah I've read that previously. However, on the hoist, with the suspension fully extended, the OEM length was found to be ideal to avoid placing load on the bar. I did get adjustable links so they can be easily adjusted in future if my understanding proves incorrect (probably).

Quote:

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Originally Posted by dru

How much were they to replace?

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I took advantage of the GSL sale on Whiteline kit a few weeks back, all up was well under $200 delivered, speak to Greg at GSL for current pricing.

MOOG Problem Solvers (NASCAR suspension manufactures) is what I used, couple of others on the forum use them too, designed to fix the problem, not adjustable but can be greased and not crappy plastic rear endlinks like OEM. Shipped from USA $80:00

My OEM endlinks knocked since 3000Kms standard or current aftermarket suspension, they are crap.

pretty common problem for mazda 3s, especially mpss. and what some, or even most mps owners don't realize is that a mps is already a lowered mazda 3. so if you lower it some more again, then you are going past a limit that the suspension geometry likes. and changes will need to be made.

Get the front d bushes replaced get the stock part from Mazda costs about 30$ and change that first cheapest and is usually the problem

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Our 2006 3MPS has done 110,000km. Wife drives it most of the time, and is an average driver. No modifications to the car at all, and it is maintained in pristine condition. Due to the ongoing noises, the car is on its second set of front shocks, has had the front torsion bar ends replaced with after market (good quality) ends, and have replaced the torsion bar bushes with the genuine item. I have tightened every nut/bolt I can find, but there is still an annoying thump coming from the RH front when I hit a bump - even small changes in the road surface. Any suggestions? (Have asked Mazda about a trade in on a M3 diesel, but they want me to give them the 3MPS for next to nothing.)

It's the front sway bar d rubbers I had the same issue

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For the second time - read the first post - ffs.

He has already done the d links and end links.

lower spring bush.
upper spring bearing.
front or back inner control arm bushes.
lower ball joint.

all these will also clunk when worn...

Does anyone know a ratio that the front end links should be shortened (to raise the sway bar away from the sub-frame) to the distance you've lowered the front of your car?

Would it be safe to say 1:1

Other way around I think, The endlinks need to be longer rather than shorter.

I have replaced the front sway bar d rubbers as indicated in my post. Most of the noise disappeared, but there is still an annoying clunk front RHS.
Cheers.