Mazda Rotary Club

General => General Technical => Topic started by: Kenji on February 23, 2011, 02:40:13 PM

Title: Clunking noise
Post by: Kenji on February 23, 2011, 02:40:13 PM
Started today.
I was driving along, at about 80 km/h, and suddenly I heard a loud clunking noise coming from the underside of the rear of the car.
When I press the throttle it doesn\'t make noise, when I release the throttle, it starts again: thunk thunk thunk thunk
 
Is my diff FUBAR?
 
 
If yes, does anyone have a good diff for me????
Title: Clunking noise
Post by: m1tch on February 23, 2011, 03:34:03 PM
Does the whole car judder? Mine does due to shot gearbox and engine bushes
Title: Clunking noise
Post by: Prof on February 23, 2011, 03:46:29 PM
Can you isolate it by trying neutral / clutch in / out?
 
Seems odd you get the clunking when you let off, and not whilst on the power.
 
Could potentially be anywhere along the drive train, but by isolating the engine from gearbox at the clutch, and isolating output shaft from engine with neutral - you should get an idea of where abouts the problem is.
 
I take it the clunking is speed dependant?
Title: Clunking noise
Post by: Kenji on February 23, 2011, 04:02:00 PM
clunking noise is indeed speed dependant.
i\'ll try the neutral thing tonight when I drive home tonight.
Title: Clunking noise
Post by: Kenji on February 23, 2011, 10:08:03 PM
Weirdest thing: driving home tonight, and no noises....
While this afternoon, the last kilometer of my trip was sounding like it was selfdestructing back there......
Title: Clunking noise
Post by: FDAsh on February 23, 2011, 10:25:25 PM
I had something like this too. No damage to the diff, all new bushes, sounds and feels like a flat tyre at the back. No idea what caused it but it was intermittent, regardless of being on or off the power.

Would build up, then fade away, only time it got much louder was if I touched the brakes.
Title: Clunking noise
Post by: m1tch on February 24, 2011, 12:50:49 PM
Possibily a wheel bearing on its way out?
Title: Clunking noise
Post by: FDAsh on February 24, 2011, 08:07:37 PM
This seems to be the number one possibility with mine. But its intermittent nature is the confusing bit. I\'ve had bearings go on other cars and it was a constant drone.

Dave and Pip figured it could be a bearing just outside tolerance, getting warm and knocking before cooling off. But there\'s no play in the wheels when jacked up. Odd.
Title: Clunking noise
Post by: Kenji on March 06, 2011, 06:20:45 PM
This afternoon it happened again. Starting softly, then increasing in noise.
Than, after just a minute, it disappeared again.
 
When I heard it, I stepped on the clutch pedal, and the noise remained.
 
Both me and my girlfriend thought the noise was louder from the rear left, than the right side.
Title: Clunking noise
Post by: neil_jdmr on March 06, 2011, 06:38:22 PM
a long shot but check all your wheel nuts/bolts are tight
Title: Clunking noise
Post by: Kenji on March 07, 2011, 02:41:46 PM
All wheel bolts are tightened at 120 Nm.
Title: Clunking noise
Post by: Kenji on March 08, 2011, 01:23:35 PM
jacked up the car this morning and had a good luck underneath.
 
Wheel has no play when I move it. Axles also fine, no leaking dust boots.
 
Strange that it comes and goes. Sometimes it lasts a bit longer, sometimes it stops by itself after a minute.
And it doesn\'t happen every time I drive either.
Title: Clunking noise
Post by: neil_jdmr on March 08, 2011, 05:42:25 PM
Start looking at brakes maybe mate.  Stuff on discs
or loose calipers/pads etc
Title: Clunking noise
Post by: RotRex on March 08, 2011, 06:40:23 PM
A long shot from a newbie who is hardly mechanically minded.....I had a clunking noise once and it turned out to be a bolt that was loose on the abs computer. The computer housing would intermittently hit against the car body and make noise. Tightening the bolt stopped the noise. How it had got loose, I know not.
Title: Clunking noise
Post by: Kenji on March 26, 2011, 12:24:13 PM
Found it. Turns out the uniball where the rear lower camber arms connects to the wheel hub has developed play.
So I hacve to replace the uniball or the entire camber arm (see my Wanted ad!!!!!)