[jpack]

When braking from 35 mph or greater, the steering wheel of my 2008 AWD FX35 shakes. It does not do this at any other time. What is the likely cause?

 

[IlovemyFX]

Sounds like your front disc brakes need to be machined. Mine did the same thing at about 30K Kilometers. I haven't had a problem with them since and am now at 120K Kilometers.

 

[sixtz4me]

Have your front rotors turned (machined)

 

[landmannnn]

Do people machine rotors nowadays? I have always bought new.

It is likely that you have warped the rotors, normally this is done by sitting with your foot on the brakes with them hot. This creates a cold patch which means they cool unevenly.
You could try rebedding them. Generally done by braking fairly heavily from 70 to 40 three times in succession, then let them cool.