DC Down Under was a journey of contrasts. The arid desert and the two city raincoats. The humble roadside stalls and our shiny, cutting-edge car, an electric Kia EV6. And of course, the great success of the car crossing the desert, faced with the ignominy of having to park it early due to the mysterious problem with the brakes. But what was it that went wrong?
[Welcome to project DC Down Under, a project in which The Drive sent the indomitable Lewin Day and James Gilboy across 1,700 miles of the Australian Outback over the span of five days in a Kia EV6. Electric cars in 2022 thrive in places where there’s a healthy number of public chargers; doing so across the Nullarbor Plain is another matter altogether. This is the eighth story in the series. You can read parts one, two, three, four, five, six, and seven here.]
More brakes, more problems
Just over a week after we said goodbye to the car in Katanning, we finally heard from Kia Australia about its fate. “I have received confirmation that one of the hydraulic pump valves within the ABS control unit has malfunctioned. The brakes still worked as they should, but this caused the brake alert to come on,” they told us.
The valves in an ABS system are used to modulate the braking pressure at each wheel. If a wheel locks up, the valve corresponding to that wheel releases some hydraulic pressure in the brake caliper, allowing the wheel to rotate for more effective braking. When active, the ABS system continuously modulates the precise level of brake pressure using these valves many times per second. The system applies the maximum possible brake pressure, right at the wheel-lock threshold.
If these valves are stuck or malfunction, it can affect the vehicle’s braking performance. In certain positions, stuck valves mean the ABS system can’t engage on one or more wheels, meaning they act like normal old dumb brakes. This can cause the vehicle to drift to one side in conditions where one wheel locks up and the others modulate normally.
Alternatively, if a wheel’s valve is stuck in the open pressure bleeder position, it means the brakes will not apply properly to that wheel. This can cause the vehicle to pull to one side under normal braking.
In the minimal brake test we did, I didn’t detect any pull to one side or the other. Most likely we wouldn’t have had full ABS engagement in an emergency stop, and there may have been some jerks. Otherwise, however, the car would still have been driveable under normal conditions.
When I explained why we cut the trip short, the big debate centered on whether it was the right decision or not. I still stand by that decision. We didn’t have any information on what was wrong with the brakes, and the dash continually beeped demanding we stop.
Even if I knew then what I know now, I’m not sure I’d choose something different. If we had a complete picture of what was wrong, we could have chosen to limp the car. Driving at a slower speed would have minimized the risk of losing control if one wheel failed to brake properly.
It would have been cooler and much more convenient to complete the trip that way. Also, we would have gotten great photos of us pulling the car into Perth.
However, it’s always hard to take risks like that when you’re driving someone else’s car. Plus, the incessant beeping would have driven us crazy in the three or more hours it would have taken us to get to Perth.
I wouldn’t have tasted much, anyway. The hard part was getting the Kia across the desert, through cities with double-digit populations and roadside homes with even fewer. Getting an EV from Katanning to Perth isn’t really that hard; there are enough fast chargers scattered around that it’s pretty routine.
In any case, it’s nice to know what really went wrong. In a way, it feels vindictive that there was an actual mechanical problem. If it had been a random software glitch that went away, we would have looked dumber for stopping in hindsight.
However, instead of ignoring the obvious signs for our own convenience, we think rationally about the situation and make the difficult decision to stop. We all came back in one piece and were able to tell the stories of our journey through the desert. No matter how it ended, that feels like a win.
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