Talk:Hand brake

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[edit] Relative strength of handbrake in manual and automatic cars

In my experience, handbrakes in automatic cars tend to be weaker than in manual cars. Occasionally I have driven an automatic with the handbrake "full on", without even noticing; after a mile or two, I might notice the engine straining a bit, or an unpleasant smell, or perhaps a red light on the dash. In a manual car, this tends to be impossible - even with the engine revving off the scale, the handbrake should be strong enough to stall it before the clutch is fully released.

Is this a general feature, or just a coincidence in the cars I have driven? Mtford 08:52, 13 October 2006 (UTC)


It is a coincidense. Go to a new car dealer and test drive an automatic and a manual version of the same car and test their brakes and you will find they have equal stopping power. What I am sure you notice is that many who use automatic transmissions do not maintain their parking brakes to the same level as those who drive manuals. This is because the manual driver has a greater need and more frequent use of the parking brake. I know of many who drive automatics and do not use the parking brake at all. I know of none who drive manuals who do not use the parking brake on every trip.Z07 14:31, 27 January 2007 (UTC)

I have designed parking brakes for the leading global manufacturer of parking brake systems for the last decade. Functionally there is no difference in a automatic and manual transmission vehicle. The parking brake system is regulated in the United States by FMVSS-135 which states that hand brakes must be capable of holding a passenger car or truck under 10,000 lbs gross vehicle weight (GVW) with the vehicle loaded to GVW on a 20% grade with 90 lbs maximum input to the lever with the transmission in neutral. 207.89.251.10 19:21, 30 August 2007 (UTC)

Also, automatic drivers, especially those who don't normally use it, are more prone to forget it is on and drive around wearing out the brake shoes - so maybe Mtford is on to something. And obviously a torque converter won't let an auto stall, which makes it much easier to drive around with it on. I know I've done it... 220.244.238.174 23:37, 24 April 2007 (UTC)

[edit] Difference between handbrake and footbrake

The article doesn't explain why a car can be stopped under control more easily with the footbrake than with the hand/emergency brake. It even states, near the bottom, that the two brake systems may use the "same mechanism". Why then, does a "handbrake turn" only occur with the handbrake? Surely readers should not be encouraged to try using the handbrake next time they need to slow down on a busy road in the rain at 70+ mph!

The handbrake or parking brake only operates the brakes on (typically) the rear wheels. The reason a handbrake turn works is because locking up the rear brakes causes a vehicle to oversteer, or swing its rear out, whereas with the normal brake pedal, the front brakes do most of the work. Additionally, the regular brakes are tuned to be much smoother and longer lasting under motion, whereas the parking brake is meant to only be used to hold a stationary car stationary, and stop a car in an emergency. Neither situation requires the smoothness customers expect from standard brakes. So in conclusion, the mechanism is basically the same, in some cars, but the purpose, design, and refinement are all different, and they (typically) act only on the rear wheels. Dachande 15:02, 22 October 2007 (UTC)


Also perhaps worth mentioning that the handbrake does not normally operate the rear brake lights? Mtford 09:03, 13 October 2006 (UTC)

[edit] Parking with brake on vs brake off

im just curious because ive heard different sides of this argument, but does anyone actually know if its bad to turn your car off without turning on the parking break. Some people say its bad for the transmission while others say its only really needed if you park on a hill. —The preceding unsigned comment was added by 67.85.20.37 (talk) 21:35, 17 December 2006 (UTC).

Most auto manufacturers recommand that the parking brake be used at all times, and that the Park gear on the transmission is used as a backup only. If a vehicle is regularly parked using the Park gear only then premature wear to the transmission can occur. 81.178.235.56 14:37, 19 January 2007 (UTC)


It's not a park gear. It is a small parking pin. The wear occurs to this pin not from the load it bares but rather from the shock it takes as the vehicle rolls when the brake is let off. Thus, securing the car with the parking brake before letting off of the foot brake with the car in park will save this pin from the shock of the car being stopped by the pin. ````


Parking a car with the handbrake disengaged is a bad idea. With a manual transmission and even with the lowest gear engaged, random disturbances - like wind - will make the vehicle roll slightly back and forth (maybe an inch or so): it's an obvious safety hazard; also, transmission components clatter against each other, engine parts are unneccesarily stressed, the stopping force is weak, and most importantly - wheel bearings can be seriously damaged by false brinelling due to the small oscillating motion. ******

The reason to engage the parking brake in an automatic equipped car is not to prevent wear to the transmission. When you place the vehicle in park, release the foot brake and it rolls an inch or so then stops, that play was provided by your engine mounts. Allowing the vehicle to bounce off its mounts increases the wear they receive.—The preceding unsigned comment was added by 76.83.129.146 (talk • contribs).

If parking wore out the motor mounts then they would fail under acceleration from a stop too. There is much mor force put on the motor mounts from reving the engine than from parking. The wear on the parking prawl is indeed the reason to set the parkingbrake before letting off the main brake.Z07 13:16, 10 May 2007 (UTC)

Indeed. That play is actually because the parking pawl is not yet in one of its notches. The car rolls forward, the transmission rotates a bit, a notch and the pawl line up, the pawl clicks in (its spring loaded) and the car stops. Remember that below a couple hundred rpm, the transmission wont even begin to turn the engine, so no force will be transmitted. If you need more convincing, the torque converter isn't engaged to the transmission anyway, so even if it were to transmit force... there would be none to transmit. Nereth 12:26, 20 May 2007 (UTC)

[edit] GM had front wheel drive cars in the 1960's

This is simply wrong: "GM's first attempt at front-wheel drive cars in the early 1980s" Read about a 60's era car from GM with front wheel drive right here in Wikipedia: http://en.wikipedia.org/wiki/Cadillac_Eldorado —The preceding unsigned comment was added by Z07 (talk • contribs) 20:56, 25 January 2007 (UTC).

[edit] This entire paragraph is a red herring I'm taking it out

The fact is that millions of cars were and are built and operated safely with foot actuated parking brakes. The case refferenced in this article does not show a difference between foot and hand actuated brakes in general as the author claims. It shows that a single case of late design change resulted in a single brake lever that was not designed correctly. In no way does this show a "difference between pedal and lever [actuators]" A leg is in general much stronger than an arm. Therefore, more force can be generated by the leg than the arm.

"The difference between pedal and lever for activation of parking brakes was highlighted when NHTSA sued General Motors Corporation over the safety of their X-car family, GM's first attempt at front-wheel drive cars in the early 1980s (United States v. General Motors, 841 F.2d 400 (D.C. Cir. 1988)). The cars were initially designed to be five passenger models, with bucket seats and lever actuated parking brakes. However, a decision was made late in the design cycle to broaden the cars' possible purchasing appeal by offering them with bench seats, as six seaters; this necessitated a change from parking brake lever mounted between the seats to parking brake pedal. The pedal, however, did not have enough leverage to apply sufficient pressure to the rear brakes to hold the car on an incline, and without enough time to redesign the braking system the decision was made simply to use brake linings with a higher coefficient of friction instead, to hold the car with the pressure that could be applied through the parking brake pedal. However, this in turn had an undesirable effect; the increase in friction of the rear brakes, along with the (unusual for GM up to this time) excess forward weight distribution of a front wheel drive car and possibly GM's inexperience at the time with front wheel cars, led to a tendency for the rear wheels to lock up under braking, which led to the rear of the car slewing sideways and loss of directional control and/or spinning. The Court of Appeals eventually ruled against NHTSA and for GM, however, on the grounds that NHTSA's case for performance failure was based only on circumstantial evidence.[1] The Center for Auto Safety includes the case as one of its Safety Research Reports.[2]" —The preceding unsigned comment was added by Z07 (talk • contribs) 21:10, 25 January 2007 (UTC).


[edit] Jacking

The article makes note of jacking only in this blurb:

"It is however, particularly dangerous when used in combination with a bumper jack at the rear of the vehicle if wheel block wedges are not used; jacking one rear wheel up will allow the differential to operate and the vehicle can roll off of the jack. This can be particularly dangerous if the wheel has been removed."

Bumper jacks are not common at all in modern cars. Can you please give one example of a car with a drive shaft brake and a bumper jack? There are none unless someone has built himself a one off custom car. In that case the builder will know more about it than you or I.

What if the car has a posi-traction rear end? What if the car has the pinion gear welded?

What if it is a SAAB 900 with front wheel drive and front mounted parking brakes? Then you can lift the rear of the car all day with the brake wheels still on the gournd.

This note only adds confusion about parking brakes. I will delete this blurb and add in a note on jacking safely. —The preceding unsigned comment was added by Z07 (talk • contribs) 21:30, 25 January 2007 (UTC).

Please format your edits so they do not run together with others on the discussion page. This was inserted inside the above paragraph.Z07 13:08, 10 May 2007 (UTC)

"The article is not necessarily referring to cars. Any jack, not just a bumper jack would satisfy the conditions allowing the vehicle to roll. The trucks I work on need to be chocked before changing a rear tire because of the open-differental and driveshaft mounted parking brake."

Yes. My section on jacking mentions chocking the wheels.Z07 13:08, 10 May 2007 (UTC)

[edit] Automatic Brake Release

This statement is simply wrong: "Historically, some cars with automatic transmissions were fitted with automatically releasing parking brakes. "

The word "historically" here indicates that cars are no longer fitted with automatic brake releases. They are and the brake releases work quite safely and well.

I will alter the main article to correct this.


[edit] The First EPB System in a Production Vehicle

The first instance of EPB was not the 2002 BMW, but the 2001 Lancia Thesis. 84.64.117.245 21:59, 9 March 2007 (UTC)

[edit] Handbrake with Rear Discs?

"In cars with rear disc brakes, the emergency brake most often actuates the disc calipers (again, with much less force). However, there are examples of cars with rear disc brakes in which the emergency brake actuates a small drum brake housed within the hub assembly (e.g. the Mazda RX-5, its twin the Cosmo, and older Toyota Camrys and Celicas)."

In my experience, rear disc rotors are shaped like Panama Hats, the raised part covering the hub drum brake that is connected via a cable to the handbrake. I believe the Porsche 911, at least the early ones, had rear discs but separate inboard rear drums for the handbrake. Either way, having two completely separate braking systems make sense - i.e. in cases brake failure.

Risk of brake failure is not a good enough reason to have separate systems. Most brake failures are hydraulic related and therefore have no effect on the cable actuated parking brake. The other option is friction material failure, which takes thousands of miles of degraded performance and horrendous noises to become complete failure.—The preceding unsigned comment was added by 76.83.129.146 (talk • contribs).

I have little experience of modern American cars, maybe they do use the discs (I doubt it), but I think the author of the quoted paragraph is misled or extrapolating from limited experience. 220.244.238.174 00:00, 25 April 2007 (UTC)


I have two modern American cars with four wheel disk brakes. They both use the rotor and pads for the parking brake. They are both Corvettes. By reusing the braking componets from the main brakes unsprung weight is reduced.Z07 16:19, 3 May 2007 (UTC)

Older Corvettes used the mini drum inside the rear disk. My old SAAB 900 did not. It used the front calipers and pads.

2002+ Subaru WRX does indeed have a small drum inside the rear disk. The parking brake lever actuates shoes that press outward onto the drum to apply braking force. The rear calipers do not have any function other than as service brakes. To do a "full" brake job requires 2 sets of pads and one set of shoes. Yes, it is a bit of a pain.

I'm fairly sure all Japanese and Australian cars with 4-wheel discs have drum-actuated hand brakes. The only American cars sold in Australia are Chryslers, and they all seem to have drums as well. 60.240.161.226 10:42, 8 May 2007 (UTC)

The preceeding paragraph is incorrect. GM also sells cars in Australia. I know of GM's brand Holden, and I'm pretty sure SAAB, Opel, and Vauxhall are sold there too.—The preceding unsigned comment was added by 76.83.129.146 (talk • contribs).

GMH sell no American cars in Australia. No American-made SAABs are sold in Australia. Opel and Vauxhall models are badged as Holdens. Karldoh 12:45, 12 May 2007 (UTC)

[edit] references

Added two references. Z07 13:04, 10 May 2007 (UTC) Removed the advertisement placed by an unregistered user. Z07 23:18, 8 July 2007 (UTC)

[edit] More Detail Required

I would like to see a more detailed description (and ideally a diagram) of exactly how a hand-brake actuates the primary brake.


Marquetry28 09:25, 9 September 2007 (UTC)