Rear end noise when cornering (Torsen)...

AzzA68 · Postby **AzzA68** » Sun Nov 24, 2019 12:06 pm

G'day All,

I've been googling and searching high and low but no cigars yet...

Car is an 04 SE, more or less stock, every indication of a moderately easy life bar one decent "love tap". Chassis is true, running gear is original bar a few longevity and performance upgrades (braided lines, etc), so nothing that should cause undue wear and tear. ODO says 135k and no indications it should be higher.

Over the last 12 months or so it's developed a noise in the rear, that's audible when turning. Sounds like running on a tyre with a massive flat spot or a sidewall deformation. Noise is only present when cornering, present on left and right turns. Is becoming more pronounced and repeatable. Still only audible when the roof is up, but I don't want to be hearing how fooked it is with the roof down... if you get my drift.

Any clues or similar experiences?

flycasta · Postby **flycasta** » Sun Nov 24, 2019 1:23 pm

Noisey when cornering slow and fast?
Wet and dry conditions?
When the car is jacked up with wheels off the ground can you sumulate it?
I would think it is more a cv joint but so many things.....calipers or wheel bearings as well.

Wheel speed difference seems to induce it so your thought of diff might be correct but generally no preload on the torsens so shouldnt make a difference unless the diff/bearings are really on the way out.

My suspicions would be cv jojnts.

bruce · Postby **bruce** » Sun Nov 24, 2019 1:29 pm

Yes, unlikely to be diff with such low kays (unless there is low fluid in it - but then it would constantly noisy).

AzzA68 · Postby **AzzA68** » Sun Nov 24, 2019 1:37 pm

I was thinking CV joints or wheel bearings too, as it began with more to the right than left, but now seems to be both sides.

It's more noticeable when driving "normal" and under moderate acceleration. So turnpikes, on/off ramps, and roundabouts etc. (There's not many of the former around home, so is more noticeable on long journeys away, when everything is well up to operating temps.) Didn't notice it at a recent khanacross but my mind was on other obstacles.

I don't believe it's brake related, everything is working well, and the "pads" (edit: not "calipers") rattle slightly due to the spring clips needing replacing... So the calipers are free moving, not binding, as they should.

I've though of rigging a series of microphones to the rear end; to isolate the source/s, but haven't got that far yet.

AzzA68 · Postby **AzzA68** » Sun Nov 24, 2019 1:43 pm

Fluid was replaced, with Penrite's, 30 thousand kms ago.

AzzA68 · Postby **AzzA68** » Sun Nov 24, 2019 1:47 pm

I cannot tell if the noise originates inboard or outboard of the axles.... Would be handy if I could face rearward whilst driving, but that's not going to happen...

manga_blue · Postby **manga_blue** » Sun Nov 24, 2019 2:04 pm

If it happens when turning left then it's a right side wheel bearing. If turning right then it's left side wheel bearing. You have to Jack it up and feel the wheels turning to determine whether it's front or rear though. Last time that I did a front left wheel bearing I was convinced the noise was coming from the diff. It's an MX5 thing - the boot floor is a loudspeaker for all running gear noises, especially if the carpet's out.

AzzA68 · Postby **AzzA68** » Thu Nov 28, 2019 5:53 pm

G'day Folks,

Thanks for your input.

This turned out to be the drivers side rear wheel bearing.

It finally got knackered enough to diagnose, by spinning once lifted. There's some square balls in there for sure. Previously it didn't want to disclose itself, now there's no hiding it.

Odd that it should be that side, but that's the luck of the drawer I guess.

I'm also very glad it wasn't a CV, especially the inner joint that's integral to the shaft; they're unobtainium, nil stock anywhere and Mazda won't be making any more. Phew!

Anyone got any tips on replacing the rear wheel bearings? Anything to be careful of or is it just a case of pressing the old one out and the new one in?

Cheers,
AzzA

manga_blue · Postby **manga_blue** » Sun Dec 01, 2019 4:35 pm

Front wheels bearings are an easy job to do at home. The rear wheel bearings need a bit more skill and tools.

I've done 4 front bearing replacements at home but I've taken the two rears to a local workshop. It's a pretty simple generic job for them.

If I were you I'd go and check all the bearings. When I did the first one at around 150,000 (and about 1,000 comp laps) I found that 3 of them were actually on the way out. Track work puts much higher demands on the bearings, more so if you have turbos or aero.