Foot brake and a driver used to manual

[Myros]

two-pennorth from me

C280 w202 manual, will stall the engine if p/brake on properly.
500SL r107, squats down and goes nowhere if handbrake on properly. I haven't had the heart to try and take it any further.
My 320CDI does the same, groans a bit, creeps about an inch and sits still.
Mem's drives off as though nothing had happened.
Note to self, fix mem's parking brake.

The brake on the 202 is a pinta, as it is manual, and I'd need three feet to pass off a driving test standard hill start.
I use the parking brakes when stationary in all except the mem's, where it doesn't work that well. I also leave them in D andcover the footbrake as well, but just gently.

We've had lots of spirited discussion on this before, Iirc. Very interesting it was as well.
I wish they'd go back to an umbrella handle system like they had in the 60's. It would make the manuals more user-friendly.

 

[Razoo]

Hi , wondered if anyone else has come from a manual to auto but found a locking parking brake where the clutch should be.

I don't think you will ever hit the parking (foot) brake by accident. It's a right fiddly thing to find when you do actually want to use it.

I am VERY concerned a time may come when doing a hairy start at a dodgy junction, an automated leg response may whack the parking brake as if the clutch was there.

IMO you're much more likely to whack the normal brake pedal with your left foot if you get your auto/manual modes confused during a 'hairy' moment.

When I drove my first automatic (a 1970's Jaguar), I found my most common fault was declutching a non-existent clutch as I approached junctions and hitting the extra-large footbrake instead. This stood the car on its nose and embarrassingly stopped me several yards short of the junction.

The answer (for me) was to tuck my left leg back against the front of the driver's seat, so I wasn't able to easily use it.

I soon got the hang of autos, but when I went back to a manual, I tended to forget to declutch as I brought the car to a standstill, and stalled the engine.

Now I've got the hang of driving both and can eaily switch between autos and manuals

Razoo

 

[johnboy615]

I think after a very short time you'll become so accustomed to auto driving that your left leg will become programmed even during an emergency.
As an aside the first time I encountered a foot parking brake was when I had to drive Sir Tim Rice's car to Cornwall to pick him up. In my nievity I didn't know how to release it. I had to go back to his office and ask his secretary if she knew how to use it. She didn't! I looked SO unprofessional; what a plonker!!!!

 

[television]

I wonder if this guy drives a manual MB

 

[davidsl500]

Since moving "oop north" and having a 25' drive I do use the parking brake but only when parking, I never used it at all previously but I don't like the feeling of the car going back against the gearbox on my drive. I love the brake hold for the crawl to work.

If I'm on a slope when parking, I shift into neutral and then apply the parking brake and let the car "settle" first then shift into Park. That way you avoid that moving in park feeling..

 

[television]

If I'm on a slope when parking, I shift into neutral and then apply the parking brake and let the car "settle" first then shift into Park. That way you avoid that moving in park feeling..

Its OK for you people that have all of the time in the world to do that but it does stop the parking mechanism from jamming really tight, thus putting much strain on the gear shift components

 

[Blobcat]

If I'm on a slope when parking, I shift into neutral and then apply the parking brake and let the car "settle" first then shift into Park. That way you avoid that moving in park feeling..

The brake hold keeps it until you move it into park and as long as I then press the foot (hand) brake then I don't get the movement.

 

[turbopete]

The brake on the 202 is a pinta, as it is manual, and I'd need three feet to pass off a driving test standard hill start.

i wonder what the situation would be on the driving test in this situation if you were to take the test in a manual MB? youre supposed to brake to a halt, apply the handbrake, then select neutral. this cannot physically be done on a manual MB so what would the situation be? personally when i had my 2 manual MB's i stopped, selected neutral, holding the car on the footbrake, then applied the parking brake. as does dad now. i still prefer the manual box. my left arm still wants to change gear! only had it 14 months! (the auto, not the arm!) if the autobox ever went bang, i could be trying to create 1 of the first manual E300 turbodiesel 210's in the uk (that im aware of!)

 

[mercdriver25]

And it's effect being usually so poor that you may well drive off not knowing its on anyway..

Too right..

 

[television]

Too right..

I have answered your other post

 

[mercdriver25]

I have answered your other post

Yeah got it, Ta!

 

[muller1]

Parking brake

If your parking brake will allow you to pull off with it engaged there is something wrong with your car.

ANSWER) Most of the auto cars have crap PARKING BRAKE as the gearbox has a thingie saying P for park and that is what most people use as the parking brake is US

If you do not apply the brake when parking or whilst stopped (for more than a few seconds) there is something wrong with your driving, i.e. a fail on any driving test.

ANSWER) The Brake you refer to is on ON OFF brake you cannot feather it like a hand brake as it is ON or OFF only and use for nothing and I can assure you with a PCV, Class 1 HGV, and motorcycle licence there is nothing wrong with my driving technique.


Driving off with the brake applied is also a fail, how can you forget with a lamp on the dash?

ANSWER) If you do not use the brake for parking you cannot forget to put it off

If you do have the habbit of never using the parking brake it will sieze up and then it will not hold against a running engine and become quite stiff to apply properly, in addition the pressure applied to the service brake will be released if you are involved in a rear on collision whilst stopped and then you will be in a good position to have a second collision with the vehicle in front of yours.


ANSWER) The supposed parking even on a new run in car will not hold the car when trying to drive off with it hard on as it is so inefficient, and I do not understand what you mean when you say the pressure will be released from the servcice brake if you are rear ended causing you to have a collision with the car in front WHY WOULD THIS BE SO ??? there may not even be a car within 100 feet of your front.

It takes no time to use the brakes correctly so why not do so?

ANSWER) As far as I am aware there is no law saying you must put on the parking brake every time you stop, if every car that stopped at the lights put the car in to N or P and put on the brake just imagine the time wasted at each light change only 1/3 of the cars in the queue would get past the light change.

If you wish to use the full compliment of brakes on you vehicle each time you stop that is just fine with me but I will refrain from using the supposed foot park brake and run the risk of a siezure as it is easily cured before each test thank you.

Sorry but this is just me.

Regards.

Mike

 

[television]

ANSWER) As far as I am aware there is no law saying you must put on the parking brake every time you stop, if every car that stopped at the lights put the car in to N or P and put on the brake just imagine the time wasted at each light change only 1/3 of the cars in the queue would get past the light change.

If you wish to use the full compliment of brakes on you vehicle each time you stop that is just fine with me but I will refrain from using the supposed foot park brake and run the risk of a siezure as it is easily cured before each test thank you.

Sorry but this is just me.

Regards.

Mike

I have not used a parking brake at traffic lights for the last 60 years and I will not start now

 

[Number_Cruncher]

Sorry but I disagree. What you are saying is based on the situation 50 years ago, and as out of date as the stopping distances on the back of the highway code.

You could theoretically apply it with sufficient force to be partially effective but the effort required will simply result in cable stretch. Remember, a parking brake is a 1920's design with brake shoes and cable actuators. From an engineeering standpoint the equivalent of a bronze axe on a chainsaw world. The only exception being the electronic handbrake found on some newer cars (I use my SBC hold function which does the same thing).

The emergency stopping distances in the highway code are based upon a co-efficient of friction between tyre and road of about 0.7. That's as true today as it was when these data were first put into the HC. Yes, with good tyres, on a dry road surface you'll beat these distances, but, they remain a good guide. What's inside the brake, disc or drum, isn't important for a one off emergency stop - it's the tyre to road friction which counts.

The reason MB parking brakes aren't red hot is because they are at a small working radius - the small brake shoes do not have a decent moment arm about the wheel bearing. It's not because they're mechanically actuated drum brakes.

Mechanically actuated disc parking brakes are a true engineering foul up - a triumph of marketing to allow rear disc brakes to be fitted to cars which are too cheap to have a proper MB like parking drum brake. The disc cools and contracts away from the pad, the car runs away - as many Citroen and Vauxhall owners know to their cost!

For many front wheel drive, nose heavy, short wheelbase modern Euroboxes, a rear drum brake is the correct engineering solution - the rear brakes aren't required to produce much force - they'll probably be limited by valve or ABS, and the drum allows the easy incorporation of a safe handbrake.

I'm sure that to many I'm preaching to the choir, but, the reason disc brakes are fitted is NOT because they produce more braking force, but, because they are less affected by heat, and can therefore be used harder before they fade.

If the above paragraph sounds odd to you, consider this - before disc brakes became common fitments, vacuum servos were a rare fitment, because they simply were not needed, as drum brakes could produce adequate stopping force unaided. Disc brakes are more thermally stable not more powerful.

 

[jberks]

The emergency stopping distances in the highway code are based upon a co-efficient of friction between tyre and road of about 0.7. That's as true today as it was when these data were first put into the HC. Yes, with good tyres, on a dry road surface you'll beat these distances, but, they remain a good guide. What's inside the brake, disc or drum, isn't important for a one off emergency stop - it's the tyre to road friction which counts.

Interesting. I agree that the brakes themselves aren't the defining factor in stopping distances but advances in tyre and suspension technology, plus ABS mean that assuming these distance figures were remotely valid 40 years ago, the'd have to be close to 50% out by now. I seem to remember a test where they demonstrated on a track that a modern ford focus could outbrake any 70's supercar by a huge margin.

Mechanically actuated disc parking brakes are a true engineering foul up - a triumph of marketing to allow rear disc brakes to be fitted to cars which are too cheap to have a proper MB like parking drum brake. The disc cools and contracts away from the pad, the car runs away - as many Citroen and Vauxhall owners know to their cost!

Fair point. Not thought of that.

If the above paragraph sounds odd to you, consider this - before disc brakes became common fitments, vacuum servos were a rare fitment, because they simply were not needed, as drum brakes could produce adequate stopping force unaided. Disc brakes are more thermally stable not more powerful.

Interesting. So the reason that every drum braked car I ever drove felt 'underbraked' was really down to fade rather than overall stopping power? I guess you could make the drum big enough to provide the stoppng power but you can't really vent the heat so easily, so you'll get fade almost instantly. That, plus the loss of friction caused by the residual dust that stays in the drum and impedes the shoe application means that for stopping power they aren't going to compete with a disk setup, but should be ok for a handbrake. But equally as you say, they often make them so small that they can't do that effectively either.

 

[Number_Cruncher]

The parameters of the car that really matter with regard to braking are;

- wheelbase - the longer, the better
- height of the centre of gravity - the lower the better
- weight distribution - for braking a rearwards bias is good [rear engine Porsches do well here]

If you get these thre parameters right, it means that you can generate some meaningful stopping force from the rear axle as well as the front. As load goes forward under braking onto the front wheels, the harder you brake, the less braking the rear axle can do before it is in danger of locking - taken to extremes on motorbikes [short wheelbase, high c of g] the rear wheel lifts off under heavy braking.

One reason why modern cars do better than older cars is that, thanks to electronic control (ABS +EBD) they can come closer to the catastrophic situation of locking the rear axle. Older cars - even supercars as you mention - had to have either very weak rear brakes, or rear brakes throttled by load sensing valves, pressure reducing valves or, so-called G valves.

A drum brake as fitted to older cars was more than capable of locking the front wheels, the Morris Minor I ran 20 years ago certainly could. For an old-tech car without specialist driving skills this would be pretty close to obtaining the shortest possible braking distance the car could do.

For a given space package within a wheel, the rubbing friction surfaces of a drum brake are working at a much larger effective radius - a disc brake works at an effective radius somehere near the average radius of the disc, much smaller than the drum. So, in terms of intial braking force, a drum can produce more braking force than a disc in the same space.

>>but you can't really vent the heat so easily,

Absolutely, yes!

Drums lose out via a thermal triple whammy. As the drum rotates, the friction pulls a leading shoe into tighter contact, giving more effective application force. When the drum heats up, the co-efficient of friction between the shoe and drum reduces - which also reduces the self-servo effect on leading shoes. The third thermal punch comes from the problem that drums are less effective at exchanging their heat with the passing air - especially when compared with vented discs.

Of course, the friction between disc and pad also drops with increasing temperature.

Overall, I'm happy with the MB setup - far happier than I would be had they tried to bodge a handbrake mechanism into the rear brake caliper like cheaper makes do with varying degrees of success. It's a bit compromised by being so small, but, can easily pass the MOT, and allied with the transmissions parking pawl, I'm quite confident when parking my W124 on even steep hills.