Groaning noise from rear suspension

Hello again, all my Miata friends;

My 96 M Edition started making a groaning noise recently, from the rear of the car. You can place your hand on the body just above either rear wheel and press slightly and the car will groan. When driving it groans and I'm sure that it groans more, but road noise obscures the sound. It never gets to be a din, nor does the noise change much. But it seems definitely to be related to suspension travel, not wheel speed or engine speed.

This car has 130kmi on it and I am the original owner. Well cared for.

I have third-party replacement shocks on the car. Good quality, about

60kmi on them. The only thing I can see about them are that the boots are torn. Otherwise, they seem to be working fine. And I've never heard bad shocks make a low groan like this. Just bottoming out noises.

I jacked up the car. No obvious leaks from the shocks. No obvious damage to the alignment joints on the rear suspension. No squeaks or rattles from the exhaust and the muffler hangers look good. The anti- sway bar bushings are definitely worn, but with the car up on the jack, I haven't been able to move the suspension enough to create the groaning noise, so I'm stuck. Everything on the suspension, except the shocks and tires are original. I haven't had an alignment recently that would coincide with the beginning of the noise.

Any guesses on the source, or advice on what to do to make the groan and isolate the source? Thanks in advance for your help.

Reply to
my_two_cent
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It could easily be the worn sway bar bushings.

I don't like to replace parts trying to find the solution, but since the bushings need to be replaced and it is such a cheap and easy job, especially the rears, you might try that and see if it stops the noise.

When trying to isolate suspension noises, I have sometimes found it helpful to put one end of the car up on Rhino Ramps so that the suspension is loaded, chock the other wheels very securely, and then use a pry bar, (carefully), to find out what is causing the noise.

Good luck!

Pat

Reply to
pws

I'll second that 'emotion'! Don't forget to use some sort of waterproof lube between the bar and the bushings.

Chris

99BBB
Reply to
Chris D'Agnolo

That is the first time I've heard someone say "road noise" covers a problem! There is certainly lots of road noise in my '03.

Reply to
jim

Why do you find it surprising that road noise could mask another noise?

Reply to
Frank Berger

Why not take the rear sway bar off and see if the noise goes away? Actually, just disconnect the end links would work fine.

I haven't bother to lube my bushings. Instead, I put a washer between the sway bar brackets and the chassis. Andy Hollis(google STS2 Miata build) suggest that it's better to grind off the bushings instead, but I'm lazy. It seems to be working fine so far, knock knock.

Reply to
freddielu

Consensus seems to be that it is likely the sway bar bushings and since those are inexpensive and simple, I'll go for it. I like the idea of disconnecting the sway bar, but I might just go ahead and replace the bushings anyway, as it isn't much more work to do that.

Thanks to all for the advice.

Reply to
my_two_cent

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