CMax-Traveler Posted August 4, 2014 Report Share Posted August 4, 2014 Had a bit of a scare with my C-Max during one of my dead battery occurrences. The dealer recommend I tow the car to them, without jumping the car. So, after much hassle (ex: the tow truck didn't fit into my driveway; the shift lock release isn't where the manual says it is), we managed to load it onto a flatbed and off to the dealer we went. Got it to the dealer and it was time to unload it from the flatbed. Stepped on the brakes to gradually ease it off the flatbed and released the e-brake - the regular brakes don't work! Fortunately we were able to grab the e-brake before my rapidly-accelerating car slammed into the car behind the flatbed. *WHEW* :drop: So... if your 12v battery is dead, be forewarned - the regular brakes will only work once. After you apply the brakes once, you'll only be able to use the e-brake. Seems like a bit of a design / safety flaw to me. Quote Link to comment Share on other sites More sharing options...
fotomoto Posted August 4, 2014 Report Share Posted August 4, 2014 You still had brakes as the e-brake sort of proved. What you didn't have was powered brakes. You'll really need to mash HARD on the pedal to get any stopping power just like you have to crank hard on a steering wheel without power assist. hybridbear and JAZ 2 Quote Link to comment Share on other sites More sharing options...
wab Posted August 4, 2014 Report Share Posted August 4, 2014 You should see our Blue Ox Patriot Supplemental Braking SystemCycle 3 times during the setup process every time we tow the cmax.Check this YouTube from Blue Ox, it looks JUST the same on our C-Max. https://www.youtube.com/watch?v=4VlCE_H3HNY#t=20 Quote Link to comment Share on other sites More sharing options...
CMax-Traveler Posted August 5, 2014 Author Report Share Posted August 5, 2014 You still had brakes as the e-brake sort of proved. What you didn't have was powered brakes. You'll really need to mash HARD on the pedal to get any stopping power just like you have to crank hard on a steering wheel without power assist. I'm not sure about that... I stomped HARD and I'm pretty sure it went all the way to the stopper without resistance, and without any braking. But I'll have to try it out again next time my battery dies to be sure. Quote Link to comment Share on other sites More sharing options...
jdbob Posted August 5, 2014 Report Share Posted August 5, 2014 Here's what little the ABS operation part of the workshop manual has to say: "During certain braking events, the friction brakes can be applied directly by the driver. The brake booster push rod is equipped with an adjustable stop, once the brake pedal travels far enough to engage the stop, the brake booster push rod is forced into the master cylinder and the conventional friction brakes are applied." Quote Link to comment Share on other sites More sharing options...
hybridbear Posted August 5, 2014 Report Share Posted August 5, 2014 You still had brakes as the e-brake sort of proved. What you didn't have was powered brakes. You'll really need to mash HARD on the pedal to get any stopping power just like you have to crank hard on a steering wheel without power assist. I agree. The vacuum pump in the C-Max is electric. So with no 12V battery you didn't get the vacuum assist. The brake pump is the buzzing you hear when you walk up to the car & unlock it. Usually when the car has been sitting for hours the pump will engage when you unlock it so that the brakes will have pressure once you turn the car on. This is no different than what would have happened in a conventional car with the ICE off. You just have to mash the pedal to the floor and you'll get limited stopping power. My first car was a 1998 Chevy Lumina with almost 200,000 miles. One day I was driving along and stepped on the brakes only to find that I had to really press hard to stop. After driving a few more blocks I could tell that I had a vacuum leak and thus wasn't getting the assistance I was used to from the vacuum system to apply the brakes. I found that by shifting the car to Neutral & revving the engine I could create enough of a vacuum to stop safely by using my right foot on the gas & left foot on the brake. I turned off the busy road I was on at the first safe place to do so & called my Roadside Assistance through my insurance company to tow the car. That was a scary experience. Quote Link to comment Share on other sites More sharing options...
drdiesel1 Posted August 5, 2014 Report Share Posted August 5, 2014 (edited) No power.........No brake assist. It's simple and just the same as any other car on the road today.You had one assisted brake application due to the remaining vacuum on the booster. After thatwas used it became unassisted. Conventional ICE vehicles are the same way. Without runningthe engine you have nothing to produce more vacuum and the booster will only hold enough forthe one brake application. The C-Max had no way to activate the vacuum pump without 12 volt power. Edited August 5, 2014 by drdiesel1 Quote Link to comment Share on other sites More sharing options...
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