Rattle: bottom ball joint or top bearing?

[Lost Highway]

Hi everyone<br><br>Now for my next question... Not sure this is necessarily the best place, but seeing as tyres and wheels are related to suspension it seemed like it might be okay.<br><br>My newly-acquired car has developed a nasty rattle from the front end, it sounds to be the driver\'s side. It\'s not constant, disappearing when the road surface is smooth, so I hear it most of the time <img> and it seems to be getting worse.<br><br>My initial reaction was that it was the wheel bearing in need of tightening.<br><br>I jacked the front end up and checked both bearings for play and couldn\'t feel anything for either wheel.<br><br>On another occasion, before jacking up the car I was having trouble removing the driver\'s side wheeltrim and ended up rocking the car from side to side, at which point I heard a knocking from somewhere in the suspension (so this time the suspension was under load). Rocking at the passenger side did not result in the same knocking.<br><br>My next thought was that perhaps it is one of the ball joints. Then I discovered that instead of a top ball joint there is some sort of bearing arrangement at the top of the shock absorber (IIRC, my head\'s been full of PI woes for the last week or so!). I\'m not familiar with this sort of arrangement as this is my first big saloon.<br><br>So, my questions are these:<br><br>– which is most likely to wear, the ball joint or the top bearing thing?<br><br>– might this rattle be caused by something else that I\'ve not thought of?<br><br>I sort of hope it\'s not the ball joint because they\'re not cheap, but then I don\'t know what\'s involved with the top bearing <img>.<br><br>Thanks for your advice.<br><br>LH<br>

[Biffo]

In short it all wears, but my money would be on the ball joint. Difficult to tell from your descrition, but the other thing to check is the drag strut bush. If this is worn the end of the drag strut (the bar between the track control arm and the chassis) can vibrate against the mounting hole in the chassis. Sometimes the cup washer that the bush sits in (spot&nbsp;welded to the chassis) comes off (happended on two cars I have owned) giving the same effect.
Fun fun fun......
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[Alec]

Hello L.H.,<br><br>the top bearing is essentially a plain bush with thrust washers top and bottom, this bearing arrangement is bonded into a rubber insulated mounting plate. I suppose it is possible that the thrust bearings have worn and could knock, but i\'ve never experienced that. What does deteriorate is the rubber and could possibly fail completely. Take the plain rubber grommet off the top of the strut mount (under the bonnet) and look, if there is a problem it should be quite obvious. (Compare with the other side if you are unsure)<br><br>Alec<br>