Am I parking my car wrong?

[Pontoneer]

I guess that depends whether or not the control modules and motors continue to operate after the car has been stopped and everything turned off ?

Otherwise , the inherent flaws in the latter system remains valid .

Mercedes-Benz may have found a solution , assuming the car battery does not fail and power is not lost to the system , but I very much doubt that all other manufacturers will have .

Looking at EPC , the SLK 230 has separate discs and drums on the rear for footbrake/parking brake .

 

[ALFAitalia]

We are talking fractions of a mm here even if you get your discs hotter than they are ever likely to get on the road...as long as you put the handbrake on hard enough it's will easily take up the slack when they cool. Don't forget that on most cars the rear discs hardly do any of the braking compared to the front unless you have rear passengers and a heavy load in the boot. Often not even hard enough to keep them clean.... which is why they usually rust faster than the fronts.
My car had to have rear discs and handbrake shoes for the last MOT.....corrosion on both the disc and in the handbrake drum. So they work well at the moment.

 

[colinallcars]

Looking at EPC , the SLK 230 has separate discs and drums on the rear for footbrake/parking brake .

Being of an older design it has separate friction surfaces for the service and parking brake but in the same unit, the disc and drum are not separate items.

 

[Pontoneer]

Being of an older design it has separate friction surfaces for the service and parking brake but in the same unit, the disc and drum are not separate items.

As has been the case since 1968
, but just the same they have different cooling characteristics and it is not a problem on cars so equipped.

 

[ToeKnee]

Well , drums won't let go as they cool down , but discs certainly do .

If that was the case, and considering the large percentage of vehicles that have handbrake on the discs, there would be cars rolling down hills all over the place!

 

[Pontoneer]

If that was the case, and considering the large percentage of vehicles that have handbrake on the discs, there would be cars rolling down hills all over the place!

There are and there is ; it is poor engineering , and easily proven .

Why else would the top car manufacturers refrain from doing otherwise ?

Disc brakes are not suitable or safe for use as handbrake mechanisms .

 

[Pontoneer]

If that was the case, and considering the large percentage of vehicles that have handbrake on the discs, there would be cars rolling down hills all over the place!

There are

 

[colinallcars]

There are and there is ; it is poor engineering , and easily proven .

Why else would the top car manufacturers refrain from doing otherwise ?

Disc brakes are not suitable or safe for use as handbrake mechanisms .

I like to remain constructive but this is utter nonsense. Giving you the benefit of the doubt, I assume this is a wind up.

 

[Pontoneer]

I like to remain constructive but this is utter nonsense. Giving you the benefit of the doubt, I assume this is a wind up.

No wind up , and why would you imagine such ?

It is long established that metal expands with heat ; drum brakes are prone to brake fade with increased temperature ; drum brakes much less so .

Why else would you imagine that Merceedes-Benz , Volvo , BMW , and probably others , therefore use discs for service brakes and drums for parking brakes ?

I already alluded to personal experience of this as a result of an inferior manufacturer .

 

[ToeKnee]

Why else would you imagine that Merceedes-Benz , Volvo , BMW , and probably others , therefore use discs for service brakes and drums for parking brakes ?

Strangely, my mercedes parking brake uses the disc, my immediate neighbours BMW also uses the disc and the next neighbours Volvo S90 also uses the discs. Anymore pearls of wisdom?

 

[colinallcars]

No wind up , and why would you imagine such ?

It is long established that metal expands with heat ; drum brakes are prone to brake fade with increased temperature ; drum brakes much less so .

Why else would you imagine that Merceedes-Benz , Volvo , BMW , and probably others , therefore use discs for service brakes and drums for parking brakes ?

I already alluded to personal experience of this as a result of an inferior manufacturer .

Thanks for clarifying. It’s not a wind up, you are just ignorant of the facts.

 

[DesireeE]

Out of curiosity , although I've driven a few EVs , and am not a fan of them , what is the arrangement on them ?

Do they have some sort of transmission lock , or do they rely solely on a parking brake ?

I can recount another tale of woe , a dear friend , sadly departed , had obtained a Triumph Herald as a 'fixer upper' when he was about 16 , and , however I don't know , got it into the garage of his parents home . He would bring it out of the garage , onto the drive , to tinker about with it - all good , but one day , he decided to wash it , and moved it onto the road at the foot of his parents drive ( remember this is a project car , uninsured , unlicenced , no MOT , driver not yet old enough to hold any kind of licence ) and , walking back up the drive , heard this 'twang' as the handbrake let go , and the car started rolling slowly down the hill ; Pat ran after it , but was unable to catch it before the Michelotti designed tailfin of the Herald had embedded itself into the nose of a neighbour's PAGODA SL !!!!!! The phrase 'went the day well' comes very much to mind , and Pat's dad had to foot the , not inconsiderable , bill for repairs to the SL out of his own pocket !!!! Think Pat was in the bad books for a while after that .

Had he just left the car in gear , as my dad taught me to , from day one with cars ; it would never have happened . He taught me to apply the handbrake , leave the vehicle in gear , and on a steep hill , turn the wheels so they would choc against the kerbstones if the car ever did move . I still do all of these things if parking on a steep hill and find it utterly cringeworthy that people would ever even think of relying on nothing but a handbrake . Even worse when so many vehicles rely on handbrakes actuating against disc brakes - as discs cool they shrink and the handbrake loses grip - I have seen first hand vehicles rolling away as the handbrake loses grip when discs cool - that is why Mercedes-Benz have drums for the parking brake , because as the drum shrinks , the grip tightens rather than loosening .

Vehicle mechanics ought to be a full separate exam as part of the driving test .

100% behind you there Pontoneer and my lovely old dad taught me the same, he also said that when ever you start up the car, put the clutch in, bearing in mind there was no chance of us having an automatic back in them there good old days.

So then, what's all this about: "as discs cool they shrink and the handbrake loses grip - I have seen first hand vehicles rolling away as the handbrake loses grip when discs cool - that is why Mercedes-Benz have drums for the parking brake , because as the drum shrinks , the grip tightens rather than loosening"??? Now that really piqued my interest and I have been learning about the brakes on our lovely jalopies so I have.

When considering the handbrake efficacy, it certainly makes sense to me that there could well be shrinkage in the small surface contact of the pads upon cooling, which might be sufficient enough to loosen their grip and culminate in a fail, whereby the gravitational force and weight of a car parked on a hill might be enough to cause it to move down the said hill.






It also make sense to me that as you say with parking brakes that are drum brakes, upon cooling, the drum itself will shrink and therefore close down for want of a better expression, onto the shoes/lining inside it.







I understand from what I have read so far that as far as handbrakes go, the drums provide a stronger and better option than the discs, which are much better for faster stopping at speed, and you can get motors with front disc brakes and rear drum brakes and the rear hand brake incorporated into the rear drum and so it goes on.

Drum Brakes vs Disc Brakes: The Ultimate Comparison

Braking systems are crucial components in any vehicle, responsible for slowing down or stopping its motion safely and effectively. Among the various types of brakes, drum brakes and disc brakes are the two most common and widely used systems.

automotiveitnews.org

Advantages of Drum Brakes​

Parking Brake Integration
Drum brakes can easily incorporate a parking brake mechanism within the same assembly, providing a convenient and space-saving solution for vehicles that require a dedicated parking brake system.
Cost-effectiveness and Simplicity
Good Braking Power at Low Speeds
Environmental Protection

Advantages of Disc Brakes​

Superior Braking Performance
Excellent Heat Dissipation and Fade Resistance
Better Braking Modulation and Control
Good Wet Weather Performance
Low Maintenance Requirements

I found lots of interesting discussions about the hot-to-cold shrinkage of handbrake discs and failings and put together a few in support of your view on the subject, and I'm sure if I keep looking there will be many more out there sharing their experiences and thoughts too.

​

Handbrake failure

Hi I bought an 04' car in Sept last year. Within weeks my reverse park sensors failed and I booked a date so that garage could collect my car, from work, to take away for repair (I also wrote on his jobcard that the handbrake needs to be looked at because it comes up quite far). He then got into ...

www.consumeractiongroup.co.uk

Loading…

www.audiforum.us

Loading…

www.alfaowner.com

​

 

[Pontoneer]

Strangely, my mercedes parking brake uses the disc, my immediate neighbours BMW also uses the disc and the next neighbours Volvo S90 also uses the discs. Anymore pearls of wisdom?

Just goes to show that the bean counters are skimping on sound engineering to reduce manufacturing costs - that does not make newer cars better - quite the opposite .

 

[Pontoneer]

Thanks for clarifying. It’s not a wind up, you are just ignorant of the facts.

I am not ignorant of any facts ; in fact I am correct , and that is why Mercedes-Benz for many decades have used drums for the parking brakes and discs for the service brakes .

Random example : I can provide more if you cannot believe your eyes .

 

[Pontoneer]

100% behind you there Pontoneer and my lovely old dad taught me the same, he also said that when ever you start up the car, put the clutch in, bearing in mind there was no chance of us having an automatic back in them there good old days.

So then, what's all this about: "as discs cool they shrink and the handbrake loses grip - I have seen first hand vehicles rolling away as the handbrake loses grip when discs cool - that is why Mercedes-Benz have drums for the parking brake , because as the drum shrinks , the grip tightens rather than loosening"??? Now that really piqued my interest and I have been learning about the brakes on our lovely jalopies so I have.

When considering the handbrake efficacy, it certainly makes sense to me that there could well be shrinkage in the small surface contact of the pads upon cooling, which might be sufficient enough to loosen their grip and culminate in a fail, whereby the gravitational force and weight of a car parked on a hill might be enough to cause it to move down the said hill.


View attachment 172164



It also make sense to me that as you say with parking brakes that are drum brakes, upon cooling, the drum itself will shrink and therefore close down for want of a better expression, onto the shoes/lining inside it.


View attachment 172162




I understand from what I have read so far that as far as handbrakes go, the drums provide a stronger and better option than the discs, which are much better for faster stopping at speed, and you can get motors with front disc brakes and rear drum brakes and the rear hand brake incorporated into the rear drum and so it goes on.

Drum Brakes vs Disc Brakes: The Ultimate Comparison

Braking systems are crucial components in any vehicle, responsible for slowing down or stopping its motion safely and effectively. Among the various types of brakes, drum brakes and disc brakes are the two most common and widely used systems.

automotiveitnews.org

Advantages of Drum Brakes​

Parking Brake Integration
Drum brakes can easily incorporate a parking brake mechanism within the same assembly, providing a convenient and space-saving solution for vehicles that require a dedicated parking brake system.
Cost-effectiveness and Simplicity
Good Braking Power at Low Speeds
Environmental Protection

Advantages of Disc Brakes​

Superior Braking Performance
Excellent Heat Dissipation and Fade Resistance
Better Braking Modulation and Control
Good Wet Weather Performance
Low Maintenance Requirements

I found lots of interesting discussions about the hot-to-cold shrinkage of handbrake discs and failings and put together a few in support of your view on the subject, and I'm sure if I keep looking there will be many more out there sharing their experiences and thoughts too.

​

Handbrake failure

Hi I bought an 04' car in Sept last year. Within weeks my reverse park sensors failed and I booked a date so that garage could collect my car, from work, to take away for repair (I also wrote on his jobcard that the handbrake needs to be looked at because it comes up quite far). He then got into ...

www.consumeractiongroup.co.uk

Loading…

www.audiforum.us

Loading…

www.alfaowner.com

View attachment 172165

View attachment 172166


View attachment 172167

​

Thank you for your well researched and considered reply ; all of which I agree with .

As you were , I was also fortunate in having a mechanically competent father , who taught me exactly as yours taught you ( my dad was born in 1919 and must have started driving in the late 1930s ; his first car was an Argyll , an example of which is on display in the Glasgow Riverside museum ; he served in the army through the entirety of WWII driving everything from motorcycles to tanks , and after the war , drove buses before starting his road haulage firm in the late 1950s ) . I started driving everything from land Rovers to caterpillars in his yard , and on sites , as soon as I could reach the pedals ; my younger sisters were taught the same ) ; it is sad that so many younger drivers have not had the benefit of such instruction .

My dear ex , with whom I remain friendly , as she is the mother of our 16 year old son , is , as I imagine you are also , a very competent and enthusiastic driver , and also mechanically very competent ; both of my ex's ( I had an earlier partner , with whom we have a 38 year old daughter , and my first partner wasn't only an enthusiastic and competent driver , but a keen motorcyclist , having had two BSA motorcycles before I met her ; alas I only had a 125cc Honda ) ; they both routinely parked in gear and , if on a steep hill , turn their wheels to block against the kerb , as instructed in Roadcraft .

it beggars belief that manufacturers , which I listed earlier , who previously provided 'no compromise' braking systems , have cut costs to the point that they have .

This is just another reason not to buy a Mercedes car any newer than the W124/140/129 series .

Most later models are compromised , and therefore inferior .

 

[OneForTheRoad]

I am not ignorant of any facts ; in fact I am correct , and that is why Mercedes-Benz for many decades have used drums for the parking brakes and discs for the service brakes .

Random example : I can provide more if you cannot believe your eyes .

View attachment 172168

Think they went electronic hand brake around 2018. Also .

 

[Pontoneer]

Think they went electronic hand brake around 2018. Also .

That does not confirm that security of the parking brake is monitored while the vehicle is unattended .

Unless security is monitored , and adjusted ( which I doubt ) then disc based parking brakes are inferior and a cost cutting exercise .

 

[colinallcars]

I am not ignorant of any facts ; in fact I am correct , and that is why Mercedes-Benz for many decades have used drums for the parking brakes and discs for the service brakes .

Random example : I can provide more if you cannot believe your eyes .

View attachment 172168

You are clearly ignorant of the fact that MB, BMW, Volvo and most other manufacturers use electric motors acting on pads and discs in their newer designs. No one is disputing that metal contracts when it cools but you seem to contend that brake system manufacturers have overlooked this and that their newer designs designs are dangerous. Think of the liabilities they would be exposing themselves to. You’re talking nonsense.

 

[OneForTheRoad]

That does not confirm that security of the parking brake is monitored while the vehicle is unattended .

Unless security is monitored , and adjusted ( which I doubt ) then disc based parking brakes are inferior and a cost cutting exercise .

That's when the gearbox parking pawl comes in handy I guess .

Having had both systems , I know which id rather have .

 

[whitenemesis]

As the discs cool and shrink (by a very small amount) the pressure in the braking system will continue to press the pads onto the disc. The pressure whether by tension in the handbrake cable or from the hydraulic system doesn't just stop when parked up