Do we have brake override?

[Loren]

Geez again.

Everybody... go find yourself a deserted back road somewhere where you have plenty of space and nobody around. Accelerate to 45 mph, turn OFF the ignition and try to stop your car.

Now, do the same thing again, only press the brakes lightly several times before actually trying to stop the car. This will deplete much (maybe all) of the brake booster vacuum. You'll know when you run out of vacuum, the pedal will get harder. Then stop the car. It will take a bit more pedal effort than you're used to, but you CAN still stop the car.

Do the same thing from 60 if you need to, just to give you more time to bleed all the vacuum from the brakes. Feel what it feels like. Know what to do. Someday you might find yourself in a situation where your engine has quit, or some mysterious vacuum leak has occurred, or some part of your brake booster has failed... it's GOOD to know what this feels like, and it's good to know that you don't need to PANIC and assume that the car doesn't have enough brakes to stop. It does.

Aaaaaand, just to be sure I'm not leading anyone astray, I just went out and TRIED IT. 45-60 mph, cut the ignition, press the brakes a few times (it takes 6-8 presses just hard enough to get the brakes to engage to deplete the vacuum), and then stopped the car with no power assist. Does it take a lot more pedal effort? Yep. Is it impossible? Far from it.

Again, TRY IT. This is one of those things that could save your life someday. The more you know, the less likely you are to panic when something goes wrong.

Oh, and if I was recovering from a stuck throttle, I wouldn't waste those 6-8 presses of the brake pedal... I'd simply find a place to pull over and brake ONCE to stop... and I'd have full assist to do it. (you might want to try that, too... just to prove it to yourself)

[sbergman27]

Originally Posted by Loren

Geez again.

Want to hear something *really* amusing? My Chevy Sprint, curb weight 1680lbs... and that's 33% lighter than the Yaris, and a featherweight car by any standards... has power brakes. (My brother chides me by calling it my "turbocharged go cart". Though I steadfastly remind him that it's not turbocharged.)

What in the world did all those drivers of pre-1930 5,000lb Cadillacs ever do without power brakes? Careen around and crash into each other, I guess. I've been in positions, over the years, where stopping my 5200lb '68 Fleetwood, without vacuum, was called for. It's definitely more difficult. But doable. Not a job I'd put my grandmother on. Especially since she's dead.

Interesting point about manual shifting. I drove a 1992 Geo Metro for a while where the automatic shifting was (very) unreliable. Not knowing what it was going to do was more annoying than just doing it myself. So I disconnected its shift solenoid connectors, and treated it like a semi-automatic. Manual shifting... but with no clutch to mess with.

-Steve