My Deere 175 hydro will not start. When turning the start switch and holding down the brake, I don't hear any solenoid click and nothing happens. Recently, I had to press down on the brake several times before it would start. The battery is charged.

Hi,
I think that you may have all the clues you need. My guess is the brake switch which should be on the right at the base of the dash. Sometimes it is damaged by battery acid since it beneath it; corroded terminals will do it just as well as a bad switch.
Peace,
Clarke

Still no good. Jumped brake solenoid with no results. Any more help?