Electric handbrake tom-foolery
Discussion
Superhoop said:
I think there is a lot of confusion on two separate systems.. EPB = Electronic parking brake.. HLA/HHA whichever you want to call it is generally is noting to do with the EPB at all and purely a function of the ABS system..
If the EPB is applied, when you pull away, it will auto release - This isn't HHA, it is the EPB being released..
HHA/HLA is just the ABS module holding brake pressure in the system to prevent the vehicle rolling away on a gradient.. when you start to pull away, the ABS unit relieves the pressure.. It is normally pressure applied to all for calipers, not just the rears and I'm yet to see one yet that actually deploys the handbrake mechanism for this function
HLA generally holds the pressure for a couple of seconds only, then releases the pressure
HHA is generally a system that will hold the pressure for a predetermined amount of time (usually 10 minutes or so) after which, the EPB is applied by the vehicle and the pressure in the ABS is relieved.
Actually it is even more confusing than that really as technically speaking my 640 has EPB, HHA and Auto Hold (like many other models coming out now).If the EPB is applied, when you pull away, it will auto release - This isn't HHA, it is the EPB being released..
HHA/HLA is just the ABS module holding brake pressure in the system to prevent the vehicle rolling away on a gradient.. when you start to pull away, the ABS unit relieves the pressure.. It is normally pressure applied to all for calipers, not just the rears and I'm yet to see one yet that actually deploys the handbrake mechanism for this function
HLA generally holds the pressure for a couple of seconds only, then releases the pressure
HHA is generally a system that will hold the pressure for a predetermined amount of time (usually 10 minutes or so) after which, the EPB is applied by the vehicle and the pressure in the ABS is relieved.
Auto hold will sit there all day long essentially killing the effect of a TC. I use mine all the time, being an F series car it does not come on automatically but can be coded to do so. The newer G series models interestingly have it come on from start up...not sure about Mercedes but above seems to cover that off nicely. But all seem to operate in a similar "manner".
Auto Hold is a perfect scenario really as you can creep like you would usually, but not be holding the brake pedal down to kill the TC creep.
It also interestingly has HHA, now I never really used to use this until we moved, but our new drive as a slight gradient and with AH off it holds the car, but it can be annoying as i sometimes overcome it with a bit much gas and need to brake a little more sharply than I would like....
Obviously the EPB, which as said above does not auto release on mine, but will come on if the door is opened (as well as using park) or the car turned off.
In day to day use, I am not bothered, it is the potential for big bills that is a bit of a concern.
Though I did have a £300 bill for a partially seized handbrake that didnt meet MOT standards on My CLS, normally will sort stuff like that out but didnt have time so left it to the MOT place, as a DIYer you have at least half a chance to sort out a normal handbrake but with an electronic one it will more than likely rely on diagnostics and having the relevant software to sort it out.
I bet a lot of people are getting £800 bills for handbrake related stuff that would be a lot cheaper on a mechanical system.
Partly though, I think the reputation is probably as the earlier systems werent much cop and hopefully the bugs will have been ironed out, but perception is probably still based on older systems and those cars getting older.
Though I did have a £300 bill for a partially seized handbrake that didnt meet MOT standards on My CLS, normally will sort stuff like that out but didnt have time so left it to the MOT place, as a DIYer you have at least half a chance to sort out a normal handbrake but with an electronic one it will more than likely rely on diagnostics and having the relevant software to sort it out.
I bet a lot of people are getting £800 bills for handbrake related stuff that would be a lot cheaper on a mechanical system.
Partly though, I think the reputation is probably as the earlier systems werent much cop and hopefully the bugs will have been ironed out, but perception is probably still based on older systems and those cars getting older.
Wifeys Fiat 500x has random hissy fits, both going on and off. No pattern = no reproduction = no warranty claim.
I don't mind them per se, and in hilly areas they are a bit of a boon, as they put the handbrake on full, but I do wonder what happens if they go wrong, especially where I live.
I don't mind them per se, and in hilly areas they are a bit of a boon, as they put the handbrake on full, but I do wonder what happens if they go wrong, especially where I live.
Jader1973 said:
You’re doing it wrong if you had your foot on the brake. You should apply power as you lift off the clutch (as you would normally) and let the car hold against the EPB. Then either release the EPB or let the car do it itself.
Exactly the same as doing a hill start in a car with a manual handbrake.
My usual motions in any car are:Exactly the same as doing a hill start in a car with a manual handbrake.
Drive forward, stop on foot brake.
Change to reverse.
Apply handbrake,
Take foot off brake and ready throttle
Bring up revs slightly (only if the car has a pathetic engine, otherwise I use the idle torque)
Lift clutch to bite and release the handbrake Creep backwards on the clutch.
This technique has served me well but sometimes I change the order of some of the motions. The point is I use the handbrake to control setting off, not the foot brake.
In this case it was.
Drive forward, stop on foot brake.
Apply Handbrake
Take foot off brake
Change to reverse.
Big diesel so using torque to creep.
Lift clutch to bite. Before bite reached, handbrake auto released. Car lurches forward.
It wouldn't have mattered if I was on the throttle, the clutch was barely off the carpet at the time.
timmymagic73 said:
Ollerton57 said:
gamefreaks said:
Because the handbrake is a tactile, analog control. Not an on off switch.
I really struggle with electronic handbrakes on manual cars.
So how exactly do you use your handbrake in a non-binary way? I really struggle with electronic handbrakes on manual cars.
Note, I haven't had an electric handbrake in a manual car, only auto, however I have driven and owner many manual cars and only ever use a handbrake in a binary fashion.
gamefreaks has it nailed, a manual handbrake is an analog control to be feathered in perfect synchrony with the clutch and throttle.
We have our first car with an auto handbrake and it drives me nuts. Especially on a mild gradient which is too shallow for the car to think I need hill start assist, but still steep enough to allow the car to roll backwards. I'm going to be moving away in a few moments so there's no point in pulling the handbrake switch and waiting an eternity for it to ponder my input and clamp fully on/fully off again.
FTFY.
98elise said:
craigjm said:
rockin said:
curlie467 said:
Because they're s
t.
^^^ This. Huge backwards step. Utterly useless.t. Handbrake can be released slowly and controlled. Electric handbrakes are either on or off. That's a step backwards.
I've also had one stick on at the entrance to a car park (VW this time). I wasn't able to pull away without stopping the car and restating it.
I hate the things and would not have a car with one.
cerb4.5lee said:
Yes mine was an early model so I'm sure they've improved it on the later cars. I did really like the autohold when stuck in traffic on the 640d and the Mercedes doesn't have that feature.
Your Merc will have "Hold" where you give the brake pedal an extra press after coming to a stop.Is that what you are after? You are in Drive, but the car is braked and you can lift your feet off the pedals.
To go, touch the throttle pedal and it goes.
RicksAlfas said:
cerb4.5lee said:
Yes mine was an early model so I'm sure they've improved it on the later cars. I did really like the autohold when stuck in traffic on the 640d and the Mercedes doesn't have that feature.
Your Merc will have "Hold" where you give the brake pedal an extra press after coming to a stop.Is that what you are after? You are in Drive, but the car is braked and you can lift your feet off the pedals.
To go, touch the throttle pedal and it goes.
RicksAlfas said:
cerb4.5lee said:
Yes mine was an early model so I'm sure they've improved it on the later cars. I did really like the autohold when stuck in traffic on the 640d and the Mercedes doesn't have that feature.
Your Merc will have "Hold" where you give the brake pedal an extra press after coming to a stop.Is that what you are after? You are in Drive, but the car is braked and you can lift your feet off the pedals.
To go, touch the throttle pedal and it goes.
On the flat, pull to a stop in D. Hold on footbrake, or press P and take foot off brake. Parking brake lever too if deemed necessary.
On a slope, brake to a stop, when you want to move away, release brake pedal, the car will hold itself until accelerator pedal is pressed, no need for the (manual) parking brake lever to be used.
When parking up. Come to a halt, switch off engine and Park is automatically engaged. The manual parking lever is convenientally and conventionally close-by so I pull that up. After I gather my keys from the cup holder/store box, I give the manual parking lever a second pull, and sometimes get another notch on it. It all seems quite natural, convenient and logical.
Pica-Pica said:
Come to a halt, switch off engine and Park is automatically engaged. The manual parking lever is convenientally and conventionally close-by so I pull that up.
Many people with autos don't use the handbrake at all, but, especially if on much of a slope, you should apply it before putting the car in Park so the weight of the car isn't resting on the parking pawl.cerb4.5lee said:
RicksAlfas said:
cerb4.5lee said:
Yes mine was an early model so I'm sure they've improved it on the later cars. I did really like the autohold when stuck in traffic on the 640d and the Mercedes doesn't have that feature.
Your Merc will have "Hold" where you give the brake pedal an extra press after coming to a stop.Is that what you are after? You are in Drive, but the car is braked and you can lift your feet off the pedals.
To go, touch the throttle pedal and it goes.
I guess it depends which cars you've driven with electric park brakes as to whether you appreciate them or not.
Some manufacturers seem to implement them with all sorts of weird "features" like not letting you drive with the door open, not letting you drive in reverse without your seat belt or automatically putting on the brake when you turn off the ignition.
Others seem to just make them a direct replacement for the lever - you press the switch it goes on, press it again it goes off.
In my 2 year old Audi it seems to work fine although occasionally doesn't release when you expect it to so you end up rocking on the suspension for a millisecond until you realise.
I've owned enough cars previous to this to know people who think normal cable handbrakes are perfect are talking crap. I've had seized cables in winter locking up rear brakes when parked (Fiat), one side seized causing caliper to overheat (MINI), adjustments requiring removal of the centre console (Lancia) - they need maintenance, on many manufacturers are a cheap afterthought and are generally installed above heat shields above the exhaust so difficult to get at.
I can see why modern designers have gone for motors at the calipers and a switch in the cabin, makes much more sense.
Some manufacturers seem to implement them with all sorts of weird "features" like not letting you drive with the door open, not letting you drive in reverse without your seat belt or automatically putting on the brake when you turn off the ignition.
Others seem to just make them a direct replacement for the lever - you press the switch it goes on, press it again it goes off.
In my 2 year old Audi it seems to work fine although occasionally doesn't release when you expect it to so you end up rocking on the suspension for a millisecond until you realise.
I've owned enough cars previous to this to know people who think normal cable handbrakes are perfect are talking crap. I've had seized cables in winter locking up rear brakes when parked (Fiat), one side seized causing caliper to overheat (MINI), adjustments requiring removal of the centre console (Lancia) - they need maintenance, on many manufacturers are a cheap afterthought and are generally installed above heat shields above the exhaust so difficult to get at.
I can see why modern designers have gone for motors at the calipers and a switch in the cabin, makes much more sense.
Smiljan said:
What car is that and what does it do?
I know I drive an awful lot of makes of cars and I can't remember the last time I saw a manual brake lever. Early days they seemed like a gimmick when Vauxhall IIRC added them decades ago but they all seem to work the same these days and flawlessly. Start the engine, engage drive and drive off parking brake releases as you do so. Stop on a hill either use hold or keep foot on brake release brake and it stays where it is touch throttle and it moves forward. Come to halt on the footbrake switch off the engine, car engages park and engages the parking brake. Smiljan said:
What car is that and what does it do?
Q5 - I think it's down to when you press on, it is not instantly on/there's a delay. If you come of the foot brake too quickly after pressing the handbrake on button the car moves slightly with the gradient, not loads but enough to piss someone off if you're parking close to them.... In my experience EHB’s work flawlessly. Pull away on an incline it realises automatically and the hill assist stops you rollling backwards. Where’s the issue? Why would you need non binary input as others have mentioned? When I drive my missus car with a manual handbrake it feels like a major step backwards.
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