Parking Brake

[Joey P]

Has anybody ever noticed that if you have the parking break on you can still drive in reverse almost compleatly normally? Many times that I've set my parking break (usually just for no real reason, just screwing around) when I get back in the car and forget about it I can still back out of my driveway and then I get confused as to why I can't drive away until I go "oh, parking break." But I've still notciced that cars never seem to roll down hills with the braek set.

Also one more thing about parking breaks. When ever my dad gets a car one of the things he does is goes under the car and cut the cable that goes from the pedel to the break. He does this so that NO one can ever use it. He claims (well more then claims, he's proven) that if the break isn't used for a long time that if some one does decide to use it, it will get stuck on. So why does that happen? Does it just bind, like a window getting painted shut?

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Formerly known as Nec3f on the AOL SDMB

[AuraSeer]

Your dad is incorrect. A parking brake will not "bind" simply because it's been unused for a time.

Note the spelling of the word brake.

[RealityChuck]

The parking brake doesn't have the stopping force of the regular brake; it was originally designed as a backup system. It's enough to stop the car from rolling back, but the engine can overcome it. (You usually stop the car from rolling by putting it in Park (or keeping it in gear with a manual transmission), which does a better job of keeping the wheels from turning.)

As far as cutting the cable -- I don't know how often a modern parking brake could seize, but I doubt it's a major problem. Even if it does stick, you can still get the car moving. Further, in New York State, at least, a car without a working parking brake won't pass inspection and cannot be legally driven.




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www.sff.net/people/rothman

[Joey P]

Are you saying that it won't "bind" but something will happen, or that it will work just find after a period of not being used. If you are going with the second part then I need to clarify. The "period of not being used" generally refers to 4 to 9 years and yes I promise you something does happen that it will get stuck, it's happend to us many times.

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Formerly known as Nec3f on the AOL SDMB

[Joey P]

Ok I wrote that reply before I saw Realitychucks's post. All the vehicles that this has happend on have been late 80's.

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Formerly known as Nec3f on the AOL SDMB

[AuraSeer]

AFAIK, there's no reason for a parking brake to stop functioning just because it's unused. But if it has happened to you more than once, maybe I'm wrong. I've sent a question about this to Car Talk, the auto-repair equivalent of Cecil's column.

Anyway, if you're convinced that it is lack of use that causes the brake to stop working, why not use it once in a while? Every time you get your oil changed, apply and release the parking brake twice. This way it'd never go more than a few months without being moved.

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I'm not a warlock. I'm a witch with a Y chromosome.

What's the ambient temperature when you used your parking brake and it stuck? I've occasionally had one freeze to the brake surface on very cold nights, since moisture will tend to condense on the brake surfaces. Cutting the brake cable is -- 'scuse the expression -- terminally stupid. On all the cars I've worked with, each cable has (somewhere along its length) a turnbuckle for adjusting the tension of the cable. If this is too weak, it may be that it's tense enough when pulled to put the brake shoe in contact with the drum (or disc), but not taut enough when the release is operated to pull the shoe back.

Also, consider the possibility that this may be just a design/manufacturing defect of the cars your father owns. He may want to check with the dealer for aftermarket consumer bulletins.

[1420Vel.GN]

I have heard from many different sources that the cost and weight savings are the reasons for drum brakes.
As for why they seem to work better for forward motion, there are 2 different sized shoes, the primary shoe has less lining than the rear secondry shoe. The entire assembly will slightly shift/rotate with the drum, and the parking cable typically attaches to just 1 shoe. So if the brakes are out of adjustment, the parking brake will not utilize the entire brake surface.
Drum brakes typically have greater holding power and are more powerful than disc brakes, but since disc brakes shed heat much better than drums, disc brakes will stop a car better.
It is not uncommon for a pb cable to sieze if it has not been used for a long time and has not been lubricated. A steel cable incased in a spiral wound steel case, add years= seized cable. That aint no reason to cut the cable. (1) Properly maintain your car. (2) Using the pb will help keep the rear drums in adjustment

[Mr Thin Skin]

May I add some more bits about why cutting the parking brake's cable is a bad idea.

For Automatic transmissions:
When parking on a steep incline, one should stop the car, apply the brake, then set the car in Park. If not, the car can roll forward, or back and press against the parking pawl. This is known as torque lock.
You cannot get the car out of park. Another car has to push your car uphill a little before the mechanism frees.

For manual transmissions:
If your car stalls at a light on some sort of incline, you are going to have one hell of a time starting the car, and getting it into gear (unless you have 3 working legs). If your car is stalling at a light, you probably need to keep one foot on the gas at all times. I knew someone who could operate both the brake and accelerator at the same time, but that's foolish.


For both sorts of transmission,

If one wheel is stuck in mud, ice, etc, gentle application of the parking brake will allow power to be applied to both wheels, not just the one in the mud. This doesn't apply to all differentials, just most of them.

Finally,
Why disable a safety feature of you auto.

[ChiefScott]

Ah, the folly of youth. Gone are the days when I could just "screw around" in Dad's car.

[DougC]

- - - Sometimes the calipers or drums themselves can get temporarily stuck, if the hoses are worn enough to collapse after you let off the brake pedal. You just start smelling the brakes smokin' and you pull over and wait 15-30 minutes or so (they do release on their own after a while). - This seems to happen a lot with four-wheel drives with big-mutha tires. It is particularly a problem if you get max-size tires and change out the regular master cylinder for a larger one and don't get stronger brake hoses, but the one I used to have had 38-inch tires with the original master cylinder and hoses and it did it too every now and then.
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- Redneck four-wheel-drives are fun, but economically it's like digging a hole and tossing money in every couple days. - MC

[Danny]

I had a parking brake problem in an 85 Dodge van. The brake cable extends to the rear of the car completely exposed after it exits the metal cable hose underneath the front of the van. Moisture, or even water splashed into the opening at the end of the hose will usually rust out the cable/hose after about three years so that the cable cannot move anymore. That is why a lot of cables have an expandable rubber boot where it exists the hose. But not on this van. Aside from having to keep grease on the cable, you must also make sure this rubber boot is not cracked if it exists. This same cable problem also exists with the accelerator cable on an 86 VW Vanagon where it exits above the engine. If the rubber boot cracks, the cable will have to be replaced rather quickly. It will cause the accelerator to be stuck. Quite dangerous.

[Danny]

By the way, it is a really BAD idea to cut the parking brake cable. I had one occasion where I lost brake fluid and had the pull the parking brake to stop!

[Joey P]

My dad is a self procliamed car expert though and really knows what he's doing. In the 10 years and 200,000+ miles he's put on the Econline never once has the parking break been used nor has is needed to be used. Also he's one of those people that "ya just don't argue with" if you know what I mean.

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Formerly known as Nec3f on the AOL SDMB

[whc.03grady]

BTW, a properly adjusted parking brake should kill the engine, in a manual anyway. I mean, if you try to drive with it (all the way) on, you shouldn't be going anywhere, and if you are, the PB needs to be tightened.
An aside:
My circle of friends and I have always referred to parking brakes as "emergency brakes", or "e-brakes". I guess it depends on your driving (or parking) theory.

[Rich Hall]

My parking brake, only used on hills, is a cement block in the trunk of my Tercel.

[bantmof]

I knew someone who could operate both the brake and accelerator at the same time, but that's foolish.

Nah, it's not foolish - in fact, in many situations it is the best driving technique. It is called "heel-toeing", and it is used to rev-match the engine to the next higher gear when downshifting before a turn while simultanously braking. It's a common technique - I do this all the time.

The technique is used like this:

1. Coming up to a turn, say you're in 4rd and want to be in 2nd just before beginning the turn.
2. You use your left foot to depress the clutch. This ties up one (1) foot.
3. You have one (1) foot remaining, and you need to simultaneously brake to slow the car down for the coming turn, and apply some gas to increase engine RPM to match to the required RPM in 2nd gear shortly before beginning the turn. So you use part of your foot to depress the brake, and part to depress the accelerator. You can control the extent of each by rocking your foot laterally. Only a small amount of gas is needed because there is no load on the engine.

Of course, you don't _have_ to do this, but proper rev-matching will save wear and tear on your clutch plates and make your driving much smoother (and less likely to break traction in low traction conditions). There are other ways to accomplish this rev-match such as slowing down further in advance of the turn than you need to and then transferring one foot off of the brake to the gas, but this is sub-optimal for obvious reasons.

--
peas on earth

[Rodd Hill]

Joey P said:

My dad is a self procliamed car expert though and really knows what he's doing...Also he's one of those people that "ya just don't argue with" if you know what I mean.

I think he's one of those people "ya just don't drive with" if you know what I mean!

[Joey P]

Actually he's one of the best drivers I know.

Also as far as everyone saying that the brake isn't adjusted right. I've seen this happen (being able to reverse, with the brake on but not go foward) on many cars.

And just so everybody knows the question was "Why does the brake bind" not "What is your personal opinion on cutting the cable?"

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Formerly known as Nec3f on the AOL SDMB

[mangeorge]

And just so everybody knows the question was "Why does the brake bind" not "What is your personal opinion on cutting the cable?"
---Joey P
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Methinks ole Joey already knows all the answers.
Peace,
mangeorge

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Work like you don't need the money.....
Love like you've never been hurt.....
Dance like nobody's watching! ....(Paraphrased)

[Big Iron]

Forgive me if this has been covered already -- I read some of the posts hastily. The following only relates to my experience with manual transmissions:

1. The parking/emergency brake should also keep you from going in reverse.

2. The brake doesn't need to be cranked all the way back as far as it can go -- 4-5 clicks should do it for most vehicles. By cranking it too hard, I think you can wear it out.

3. That Opalcat cracks me up!

[TheIncredibleHolg]

My experience, referring to manual transmission:

1. Parking brakes, if pulled all the way, should stop you from going in either direction.

2. If they're not pulled all the way, or if they're maladjusted, I can think of another reason (except asymmetry in the mechanism, as 1420Vel.GN suggested) why going backwards is easier: different transmission ratio. I'd assume that ratio is lower (or should that be 'higher'?) in reverse gear than in first gear so there's more force on the wheel.

3. As someone already pointed out, PBs are a safety feature you shouldn't just disable instead of repairing it. I don't know about the U.S., but in Germany, you'd lose your operating license (correct term?) and insurance coverage over a thing like that.

4. My father is a great driver as well, big mileage, no accident in 35 years, blah, blah. But he sure isn't perfect, and I'm mature enough to make up my own mind about what's right or wrong, in driving and all other things.

[Danny]

Let me see if I can cut to the chase:

1. Cables, or brake mechanisms can rust if not properly checked, maintained, or replaced and will bind over time. Its as inevitable as old age.

2. I believe the drum brakes frequently used in the rear where the parking brake is located is designed to float so that as you apply the brakes when rolling forward, the mechanism will reposition itself to apply even more pressure to compensate for heat fade. This is sort of like the action of inertia reels in your seat belt.

3. This same float will work in reverse when backing up, releasing some of the pressure, thus making it less efficient in reverse. That is why it is easier to overcome the brakes in reverse than moving forward. The moral is not to speed in reverse, not a likely situation normally.

4. When parking facing uphill, the brakes only have to overcome the weight of the car, not any additional force applied by the engine, or momentum in motion. Therefore, even if it is less efficient in reverse, it is more than adequate to hold the car in place. It is of course prudent to turn the steering wheels into the curb when parking downhill and away from the curb when facing uphill.

5. Cutting brake cables is just plain STUPID.

6. Incidentally, they use drum brakes more often than disc brakes in the rear because of the need for parking (or emergency) brakes. Disc brakes must be applied hydraulically, while drum brakes can be applied with a cable. It needs less pressure. Besides, it gives a seperate mechanism to apply brakes other than the main system - an additional safety feature.

[TheIncredibleHolg]

Danny wrote:

It is of course prudent to turn the steering wheels into the curb when parking downhill and away from the curb when facing uphill.

Why the latter? If you roll backwards, is it desirable to roll away from the curb? I'd rather turn the wheels toward the curb in both cases.

[Mr Thin Skin]

The rear brakes on my Jaguar are both disk and drum. The drum is for the parking brake, the disks for the hydraulic brakes. I suspect than most 4 wheel disk brakes use this sort of combination.

[Danny]

TheIncredibleHolg writes:

"If you roll backwards, is it desirable to roll away from the curb? I'd rather turn the wheels toward the curb in both cases."

If there is a curb (sidwalk, barrier, etc.), and you are parked say less than a foot from it facing uphill with the wheels turned AWAY from the curb, then if you roll backwards, the front wheels will hit the curb first thus preventing any further motion. This will allow for less motion than if your wheels are turned into the curb.

What you say will be true if there is NO curb. Then you should turn into the curb facing uphill or downhill.

[TheIncredibleHolg]

Danny, I'm quite aware of what you say. But I still prefer my way for at least two reasons:
1. It works even if you're further away from the curb or if you don't turn the wheels all the way.
2. You can't do it the wrong way round by mistake. (I admit, this is for the easily confused.)
And I suppose the difference in distance travelled is negligible.

[Danny]

I think any attempt at turning the wheels is better than not doing anything! I see it all the time where people park on the hills without turning their wheels. Belief me, I try not to park downhill from them!

Just a minor aside: the difference between letting the steering wheels hit the curb or letting the rear wheels hit the curb can be great even if you park close to the curb. This is because the rear wheels are "at the center of the circle", so to speak. It will require a very large motion of the front steering wheels in order to obtain a very small amount of motion in the rear wheels. I have seen many times a car parking uphill that had the front swung halfway across the road before the rear wheels hit the curb to stop.

[TheIncredibleHolg]

I think any attempt at turning the wheels is better than not doing anything!

I think we can agree on that. Even if you miss the curb completely, you'll only roll in a semi-circle until you're crossways to the slope, instead of going all the way downhill!

[Joey P]

One of the things we were taught in driving about this subject was that after parking (assuming you are close enough) and you've turned the wheels (so the steering wheels would hit the curb) to put the car in neutral and very very slowly let it roll until hit touches the curb (but not so much that it jumps it). Then even if anything does happen it most likely won't be able to pick up the inertia required for it to get over the curb. Of course this doesn't work without a curb.

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Formerly known as Nec3f on the AOL SDMB

[TheIncredibleHolg]

Joey, I think you'd have to do this very gently, and stop as soon as you touch the curb, so as not to damage your tires if you do this often. It's not hitting the curb but standing for a long time with a sharp dent in the tire that is harmful.

I learned some questionable things in driving school. One was to always pull the parking brake. Not the brightest idea in deep winter. Another was to stand in first gear at a red light, foot on the clutch (manual transmission). Presumably, you'd be able to start sooner when the green light came on, with less risk of stalling the engine in a hurry, especially as a beginner. But I think it's not unlikely for some greenhorn to slip off the pedal some day and crash into the car in front of him.

Nothing like being critical and making up your own mind.

[Danny]

In deep winter...yup, and don't lock your doors either.

Of course we won't mention that someone will try the Lewinsky Reach maneuver while standing on the clutch at a red light!