Engine off, no brakes -- a FUN question


#1

This is more of a it happened to me post than anything, stimulated by the “Coasting downhill post” earlier this month.



Any of you have any good stories about the time you or a loved one decided to “coast” and lost control. And, of course, this is also an educational post for those who don’t realize the consequences.



One fine summer day, the sun was shining, the birds singing, when I told my 17-year-old son to back the minivan down the hill a bit because I was going to wash my car.



Dear son, decided that since the driveway is mostly downhill that he did not need to start the van.



Now, he was smart enough to know that he needed to turn the key so the steering unlocked, so he did and merrily started rolling back. The brakes worked twice according to him. And --THEN-- all of a sudden, they didn’t work.



Well, they would have, if he had had the strength of five men in his legs.



The outcome could have been worse, van rolled into three maple trees, causing about $2,700 in damage to the rear liftback, according to the local body shops.



I managed to replace with a junkyard door for $800. Son was uninjured, but learned a good lesson about power brakes – and State Farm Insurance never heard about it…


#2

They are not called “power brakes” for nothing. When not energized by the engine, YOU have to provide all that POWER to stop the car. The same is true for “power steering”. I don’t know if electric power steeing will steer the car with just the key on, at least until the battery is dead.

Thanks for a good & timely post!


#3

I have driven lots of cars without power brakes (or power steering). Frankly, I don’t remember any difficulty. Is a car with power brakes but no vacuum boost that much tougher to stop?


#4

It depends on the car.

50s and 60s car with their drum brakes could be a real challange. Fade was a real problem back then. Disk brakes actually can take more force because drum brakes if properly made actually have a tendency once engaged to add force to the process. The friction actually helps pull the shoe toward the drum surface. Without boost disk brakes can take a lot of pressure on the pedal, but on the other hand they don’t fade.

Maple trees, on the other hand, are pretty much guaranteed to stop you.


#5

I think there is a difference in the way the master cylinders are designed. I’ve compared my '76 Chevy truck without power anything to a similar truck with all the bells and whistles. Both trucks had pretty similar brake feel in terms of how much effort it took to stop, although the truck with power brakes seemed like it was easier to slow down without locking up the wheels. So I assume there was some sort of design difference to multiply the force the driver was exerting on the non-power brake truck.

Of course, the way they compensated for no power steering is with a bigger steering wheel. My '64 LeSabre has a huge steering wheel AND power steering. With the engine running, you can steer the thing with your little finger if you want to and even with it off, it feels pretty normal for a modern car.


#6

I had a '64 Chevy Nova with power steering and the power steering belt broke on me. I drove the car for about a month that way and the only time I missed it was when parking.
I used to drive an '80-something Honda Civic and I would switch off the engine on downhills sometimes and coast in neutral and lo, the sky did not fall. The car still steered and the brakes still braked. It took more pressure to brake but the car was not impossible to stop.

It must be a miracle that I’m still alive considering all the times I coasted down hills in home-made engine-less carts with no brakes as a kid.


#7

Just a few minutes ago, I tried it with my 2008 Yaris. A mild hill with no traffic. Coasting at about 30 mph, I switched off the engine and tried stopping. It took about 6 or 7 brakings before the accumulated vacuum was used up and then the brakes needed a lot more pressure to work. However, I am 6 ft tall and weigh 200 lbs so I was still able to stop the car.
This was an experiment done under controlled conditions. I don’t recommend doing it on a routine basis. For one thing, everytime you restart your engine, the CD player pauses a while to re-boot, really annoying!


#8

My 73 Lincoln would not stop with the engine shut off. It would, but I didn’t have half a mile to wait.


#9

I have had two cars with no power brake. One was a 1950s Jeep Willy’s and the other a Le Car. On the jeep, whenever I took it in the city waiting behind the red lights on inclines I would get a cramp. I learned to switch legs on short lights. On longer lights I would put the car in gear and turn off (no e-brake!).


#10

I had a '64 Ford Fairlane that I drove without the power steering working (the hydraulic ram sprug a leak). Besides being hard to turn at slow speeds, the thing required lots more input to keep it in the lane. In those days rack and pinion wasn’t common and the power steering was generally a hydraulic ram (like you can see on the bucket of a front end loader) attached to and alongside the tie rods.


#11

I think one of the driving lessons that should be given new drivers is how a car handles without power assists. They should experience how much braking effort is required to stop without power assist and how much extra effort is required to steer when the power steering is not operating. It is really scary the first time you try to stop a car that has lost power brakes.

In fact one of the tests a driver should demonstrate before a drivers license is renewed, is to be able to steer and stop that car with the engine shut off and the brake assist reserve depleted.

JIMHO


#12

You know, I have a truck that started out having no power brakes and no power steering. When I was building it (got it out of a field missing about 1/3 of its running gear), I added beefy power brakes but no power steering. I haven’t had any accidents with it, it’s not impossible to drive by any means. But let me tell you, drive that thing with its 35x12.50 tires and no power steering around in town for a week and you’ll put a couple of inches on your biceps. :slight_smile:

EDIT: Also, people, for the love of Mike, don’t go switching off your car in traffic to play around with this, it’s so easy to switch back to the Lock position and lock your steering wheel. You can have all of the power steering in the world and it’s not going to matter if the wheel is locked.


#13

I think you have an excellent cautionary tale here. This could so easily have been five of his friends standing between the back of the van and a brick wall instead of trees.

I have a sort-of related cautionary tale. My wife and I came out from a play one evening, and walked to my car. I opened her door, let her in, and closed it. I then walked around the back of my car to get in.

About 1 second after I got around the car, the passenger in the car parked behind me decided to start the car. It was in gear. Smack. Had she started it just 1-2 seconds sooner, that would have been my legs between their front bumper and my rear bumper.

Cars are large, heavy, serious things. They need to be treated that way.