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Every time I go into rough terrain, specifically bumps or speed bumps, there is a thud sound from the front end. Thinking it might be the bushings but I'd prefer not to purchase without confirmation.

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When was the alignment last done? – hcted Dec 21 '13 at 7:26
Also, have the shocks been replaced recently? – hcted Dec 21 '13 at 7:26
YouTube "BMW Control arm bushes E46 or Z4 / Z3 How to DIY: BMTroubleU" – Allan Osborne Dec 21 '13 at 15:08

Knocking and squeaking on the Beamers front end usually ends up at the 'bottom-arm rear-bushes'. Check the bushing for excessive movement.

A bottom arm bush failure can be diagnosed on the road by a quick 'stab' of the brakes whilst driving the vehicle. There will be a thud through the steering.

Before stabbing the brakes on the road, make sure the traffic, if any, is not too close!

EDIT - YouTube Video: BMW Control arm bushes E46 or Z4 / Z3 How to DIY: BMTroubleU

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What is meant by "excessive movement"? How do you check for this on this vehicle? Where is this bushing located exactly? Do you have a picture of this or a link which would show exactly what you are talking about? – Pᴀᴜʟsᴛᴇʀ2 Dec 21 '13 at 13:51
BMW Control arm bushes E46 or Z4 / Z3 How to DIY: BMTroubleU. – Allan Osborne Dec 21 '13 at 14:05

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