pjwasho wrote:We had a similar experience. Our dealership sent a notice recommending changeout of the 2017 Chevy Bolt's brake fluid at the 25,000 mile mark. I've never before heard of an almost new vehicle needing the brake fluid changed as a matter of routine maintenance re: without having the brakes themselves actually serviced if needed. Routine brake fluid changeout is not shown as needed in the manufacturer's maintenance schedule of the car's owner's manual. We challenged our dealership's suggestion based on review of the owner's manual and our dealership quickly relented on the need for this item. Caveat emptor - "Let the buyer beware" !
Yes, brake systems should be flushed and the brake fluid replaced. That you never heard of this doesn't mean it isn't a thing. How many miles and years before flushing is required is dependent on the system design, humidity and temperature. Hydraulic systems fail far sooner and more frequently in the humidity of the tropics than in the dry intermountain west.
Back in the bad old days of hydroscopic fluids and cheap design, the heat and 100% humidity in Vietnam would cause the hydraulic systems in US Army vehicles to fail within months. Just bolting on a new part without pressure flushing the lines with fresh fluid, the water entrained in the old fluid would kill the new part within months.
Having said this, some dealers are looking to run up the service bill and manufacturers don't often mention fluid flushing in required service, as most cars today will run past the warranty period and then it's the owners nickel for deferred brake system maintenance. So yes plan on having the brake fluid flushed at some point, even if no other brake service is required.