On the FEH, driving in Low gear (not actually a gear, just old school analogy), produces enormous Regen braking when you release the foot pedal. This results in a much greater percentage of your stopping energy being supplied from Regen vs. friction brakes. If your foot doesn't have to touch the brake pedal nearly as much, then the rear brake friction brake does not engage nearly as much. Consequently, utilizing 'L'ow gear more frequently reduces all friction brake wear, especially in the rear.

Most drivers use the 'D'rive position on the gearshift, not Low, especially because we are creatures of habit, so the brake pedal has to be used more often, resulting in more friction braking, especially from the rear. Some posters on this forum say that results in rear brakes wearing out much quicker than front brakes. This anomaly is exactly backwards from non-hybrid vehicles.

This is but another of the hybrid attributes that forces us to recalibrate our thinking from traditional auto behavior.

 

I almost always use Low, and rarely apply brakes beyond the final few mph. I expect 100,000 miles+ on my pads. And the person that thought that the pressurizing of the brake system at startup contributes to brake fluid breakdown doesn't realize that that just involves a different mechanism than engine vacuum assisted brakes, since the engine is often off while driving. This allows the brakes to work the same whether or not the engine is running.

 

Agree. Since I don't live in a desert, I'm more concerned about moisture accumulation and rusting than brake wear. I personally believe that the need to flush the brake fluid is no different on the hybrid than the non-hybrid. Over time, fluid will absord moisture whether the fluid is pressurized or not. IMHO, brake fluid flush and brake pad wear are two different issues.

I also expect brake pads to last a long time on the FEH. But then, I only gently use brakes on my non-hybrid cars too because I drive them the same conservative way. Gentle pressing on the brakes after a lot of coasting creates little wear compared to John Q. Public, slamming on the brakes at every stop.

You're also correct about brake pressurization, because the car has to be ready to use the friction brakes from the moment the shifter is moved from Park - Because it does eveytime under 6mph.

 

Does the HCHI or HCHII have the fully brake-by-wire system? Do you understand the FEH braking system? Pressurizing an accumulator is not just the same as engine vacuum assist and the pre-pressurized system is in the FEH brake system design as much more that just an assist because the engine is off. [There is no "master cylinder" to vaccuum assist]

The pressurization suggestion was in response to trying to imagine reasons why someone would recommend brake fluid flush and replacement - and further suggestions that the brake fluid gets energized less than in non-hybrids. I think we put that to rest - brake fluid service at 32K miles is probably not needed unless the system was contaminated.

 

I think Ken explained it very well so I will thank him for doing so. If you drove an FEH you would probably understood "what" I was saying without an explanation.

I know you are a smart guy wwest but your ignorance of the workings of the Escape hybrid shows almost every time you post about it. They are different in many ways from regular cars and very different even from other hybrids.

The way the brakes work is just one of many ways they are different.

 

OP: There is no such thing as a lifetime conventional DOT 3 or 4 brake fluid....they all must be changed. Most fluid manufacturers would indicate a 2 year interval. ATE, the fluid I use, indicates 3 years. Failure to properly service the fluid is the number one cause of brake system component failure. The fluid is hygroscopic...it attracts and absorbs water, which lowers the boiling temperature (bad) and leads to corrosion (also bad). Your dealer's recommendation at your mileage is quite appropriate. The charge might seem high, but there is more to flushing the system in a FEH. You can not bleed the brakes without removing the high voltage battery service "fuse".

 

Why is there NO mention of brake fluid maintenance in the Owner's Guide or Scheduled Maintenance Guide?

Is this a hybrid specific statement or for cars in general?

It seems to me that pad wear is the potential number one cause of brake problems as they are the part designed to be most easily replaced.

 

IMHO anyone who makes / sells brake fluid is going to tell you to change it regularly.

Between myself, my parents, and my brother & sisters, we have used about 20 cars over the past 25 years. Our family keeps cars 150,000 miles on average ( 10 years or longer ) and 3 cars in our "fleet" are now over 20 years old. The cars are Ford, Chevy, Nissan, Toyota, Honda, Buick, Oldsmobile, Pontiac, Saturn, BMW, Dodge, and maybe a couple I can't remember. All these cars were used in the city, on-pavement, and fairly mild climate of S. California. None were in excessively dirty or dusty driving conditions. All were used extensively in stop n go conditions.

None of the brake fluid has ever been intentionally changed out in any of those cars, outside topping off if we did a brake change and bled off some fluid in the process.

Unless you are a race car driver, and you EXPECT to run your brakes at MAXIMUM HEAT for EXTENDED PERIODS... I think changing fluid is a waste of time, money, and is harmful to the planet.

 

Glycol Brake fluid will absorb water in any car.

Brake fluid is hygroscopic - in other words it absorbs water. Brake fluid will absorb water through the rubber brake lines over time. Even a small amount of water can dramatically lower the boiling point of brake fluid (new fluid boils at 400F, just 3% water absorbed will boil at 300F.) The absorbed water will corrode parts and eventually cause seals to fail in the calipers and master cylinder, and rust steel brake lines.

I always go by the color. If it is clear, slightly amber in color I leave it be. If it is dark (think of the color of Coca Cola as very dark, badly contaminated brake fluid) or cloudy I change it. My old F150 went 22 years with the original calipers and wheel cylinders. I doubt they would have lasted without the occasional brake fluid change. The F150 brake fluid would turn dark around 3 years if I didn't change it. I used the truck for towing, and didn't want to chance brake fade from boiling brake fluid.

 

Potentially dangerous/expensive advice. Your anecdotal evidence is not remotely convincing.

http://www.popularmechanics.com/how_...e/1272446.html

http://www.babcox.com/editorial/bf/bf40142.htm

http://www.babcox.com/editorial/bf/bf50412.htm