E46 front end wobble

Warped rotors

Hmmm... hadn't considered that. Any other possibilities? Worn parts like tie-rods, control arm bushings, steering box?

yes

Yes

yes

plus

loose bottom link

failed shock absorbers

cracked spring

detached strut

warped bodywork

loose wheel nuts,

worn wheel bearings

damaged brake pads

flat spot on tyres

balance weights knocked off

etc.

However if the sensation is strong, you haven't kerbed it or hit anything and only happens under braking then the most likely cause is

warped braking disk(s).

Warped brake rotors can cause this.

Worn parts would manifest themselves under other conditions. If the shaking is limited to braking, the most likely cause is the rotors.

The brake pads get thin and do not disipate the heat as well as they should, and the rotors can warp. If you did a hard stop that got the rotors hot, then went into a puddle, the heat shock could cause warping. In any case, you can get new rotors for about $50 each and they are easy to install at home.

My bet: a front brake caliper is seizing.

This is pretty common. The front calipers slide back and forth on metal rods; any dirt or corrosion on the rods and the caliper seizes, then when it gets hot it gets VERY grabby.

Next time this happens, stop the car, get out, and sniff near each wheel. If you get a strong odor of brake dust that's a big clue. (You might also notice that one wheel is getting MUCH dirtier than the others). You can also CAREFULLY touch each wheel - one might be significantly hotter than the rest.

If it's under warranty, then BMW replaces that caliper, the pads, and the rotor, and then fills and bleeds the fluid.

That sounds like a possibility. I'll check the calipers tomorrow and let you know what I find.

I don'tthink there is anything wrong with the calipers, the rotors are the suspect to be looking at.