On braking, there’s steering wheel shimmy on this '99 model with just over 100K. This wouldn’t seem to be an alignment/balance problem, since other than braking, there’s no shimmy/vibration. Would shocks transmit wear this way?
You have warped front brake rotors.
Rather than having the rotors machined, you should have them replaced for just a little bit more money.
Have the condition of the brake pads checked at the same time.
Interesting. Just had the disc pads done 5000 miles ago. Guess maybe they should have checked rotor condition. At least I know the direction I’m looking in now. Thanks.
It is very common for this to happen. New rotors are thinner than they used to be, then they get even thinner from use and sometimes resurfacing. As such they become less and less tolerant of the stresses they have to deal with (mostly rapid heating & cooling) - so they easily develop minor imperfections that show up as a shimmy. It is also easy for something to go wrong during an install to increase the likelihood of problems. A couple of the most common things would be contaminated rotor/hub mating surfaces, sticky caliper slides, and improperly torqued lug nuts.
One other thing to consider, however, is that if you do feel it mostly in the steering wheel rather than in the brake pedal you probably have a rotor problem, but also perhaps other problems in the front end as well - e.g. loose/deteriorated wheel bearings, tie rods…
When the rotors get replaced (even if they can be resurfaced they likely won’t last) all of the front end components ought to be inspected.