Dirty Steering Kills Hydro-Boost
This bulletin applies to 1998-2013 Chevy Silverado models equipped with the Hydro-Boost system. Customers may notice that the brake pedal will move down or self-apply during or near full-lock turns.
This can be caused by the internal dump valve of the hydro-boost not seating properly due to contamination in the steering system.
The hydro-boost assembly is not tolerant to certain types of contamination in the steering system. The hydro-boost system is not serviceable and must be replaced.
Note that before replacing the hydro-boost system, the entire steering system (including power steering pump, lines, cooler and gear box) must be flushed to avoid reoccurrence of the problem.