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mysterious knocking

13K views 28 replies 9 participants last post by  MX5_Owner  
Front drop links or ARB bushes. The drop links on Mk3 are ball joint type...it only takes one ball joint to be minutely loose in it's socket that it creates knocking....exactly when you describe.

Quick way to check....wheel off, axle stand on sill put a jack under the lower A arm ball joint and jack up so it compresses to the point it's just taking weight of car. Get some one to rock the car and the other person hold the drop link...if it's knocking you will feel it. Do that on both sides. On the drop links there is a ball joint at each end of each drop link - making four in total.... it just takes one of them to be a bit loose to create a nasty amplified noise.....
 
I'll just go to cage and check...:thumbsup: you need two hands mind.....you need allen key to hold the spindle and a spanner to tighten nut..

But......Tightening them won't make a difference...if the ball is loose (ie it's lost it's packing grease) then it's knackered. They onoy cost ÂŁ10 each from Euro car parts. If you replace one, you need to replace both. It's a ten minute job to replace each...
 
The symptons you describe sound like the drop links....they are cheap and easy to replace. Is the sound louder on the straight over even slightly bumpy ground? I suspect it is...if it is, it is more likely drop links.

If it's more pronounced on full lock...it is definitely not drop links...and could then be the ARB bushes

If you don't have a friend to rock the car...it's no bother to take them off. The ball joints should be REALLY stiff in their sockets. If one or more is not really stiff....ie it is easy to move then that is knackered....and is what is likely causing the noise.
 
On the same subject but a different Mazda. Would this be the same on a 323f? Anyone know?
Could well be - if those drop links are ball joint types. Whip a wheel off you will soon be able to tell. Just had a quick look and theya re the same type of ball-joint drop links.

This might help Cinq :thumbsup: > http://www.club323f.com/?page_id=1177

Though....sawing them off as above is a last resort if the threads are completely rusted. WD40 or similar and wait 20 mins... is better :)
 
my pal who fitted them is aware of this particular faux pas.

I haven't been able to get a good look at the drop links but with full lock i could get a grip on it. how much movement should there be on the ball joints? When i grip the rod i can turn it through about 10 degrees.
That's normal - it's under tension so you will not be able to feel slackness but you should be able to do that. You need someone to rock the car whist holding them. A loose ball joint will be apparent.

You can't tell a loose ball joint unless you rock the car...or whip them off..... if the ball joints are really stiff to move they are fine...if they move easily, they are worn.
 
I've just read back that slushy mentioned you have new springs fitted.

Check with the guy who fitted them that the plastic shim on top of top hat where the shocker assembly attaches to the body was put back on. It is only thin, but if it's missing it will cause a knocking.