coyoteboy
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| posted on 23/5/12 at 12:54 PM |
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Electric handbrake info for those who want it
OK so I've been on to VOSA and they've been really helpful, the general outcome being that there's two key requirements. The first
is to do with the activation of it, the second the actuation.
1) The switch to activate the brake must be protected from inadvertent use. Apparently, alternative to this is a system where the handbrake switch can
be activated but not de-activated when the ignition is off. I presume this is purely to prevent accidental/malicious release rather than to stop you
accidentally hitting the brake while driving.
2) The park brake must be held in the on position solely by mechanical means (hydraulic is not mechanical and any form of electric clamping must
failsafe to the braked/locked condition without power) - so any UK (EU?) type approved electric caliper such as those found on some Audis should do
the trick just fine as they meet the same requirements.
HTH
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PSpirine
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| posted on 23/5/12 at 01:00 PM |
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Interesting!
Controlling it would be a nightmare though. All cars have a dedicated park brake module for controlling EPB - don't think it's quite as
simple as having 12v to the caliper!
Ironically also one of the most likely things to fail on many VAG vehicles (the amount of times my colleague's VAG cars have refused to release
the EPB in the morning is getting ridiculous).
Never really looked to closely at the mechanics of the electrics in the actual caliper though so it might all be a bit easier?
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HowardB
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| posted on 23/5/12 at 01:41 PM |
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sadly I have a VAG. Passat Estate to be precise, and I do not use the epb for anything, and certainly not in auto mode. It will not release, and has
on occasion caused the car to stall. It has been back to the robbers-main-dealer on a number of occasions. Having said that other colleagues have no
issues theirs,.. 
PS, I understand that the ECU has to be controlled to wind the brakes out to change the pads, so perhaps it is a little more complicated than
locost.
[Edited on 23/5/12 by HowardB]
Howard
Fisher Fury was 2000 Zetec - now a 1600 (it Lives again and goes zoom)
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dhutch
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| posted on 23/5/12 at 01:52 PM |
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We have them on some of the companies pool cars, but the thing i really dont understand is, whats wrong with a conventional cable. Its simple,
effective, reliable, cheap.
Daniel
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fazerruss
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| posted on 23/5/12 at 02:14 PM |
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quote:
Originally posted by dhutch
We have them on some of the companies pool cars, but the thing i really dont understand is, whats wrong with a conventional cable. Its simple,
effective, reliable, cheap.
Daniel
+1
Why the hell do manufacturers have to over complicate everything. One touch push button start n stop on BMWs for another eg.
If they got rid of all this crap then modern cars would hardly go wrong!!!!
"if assholes could fly this place would be an airport"
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coyoteboy
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| posted on 23/5/12 at 02:24 PM |
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A lever, ratchet, pair of cables, associated mounting points, associated lifespan of lubes, potential adjustment requirements etc are nowhere near as
simple as a switch, wire and a box of gubbins with some software to deal with control of the caliper? I think the locost brethren are still in an era
where electronics are a black art and a failure point, TBH this just isn't the case, less so if the person doing them has the time and patience
to do it as a personal project rather than lobbing them out to a deadline.
I'm considering buying a VAG caliper just to check out the interface - it won't be complex for a tiny micropro box. And the combined
weights of all parts are likely to be very similar.
quote:
If they got rid of all this crap then modern cars would hardly go wrong!!!!
Personally I've had 3 handbrake cables snap, one caliper seize on and replaced 2 other cables due to lube breakdown as they got higher milage.
They almost always need adjustment for MOT man to be happy. Couple of wires and a switch sounds like heaven to me.
quote:
PS, I understand that the ECU has to be controlled to wind the brakes out to change the pads, so perhaps it is a little more complicated than
locost.
This will be to incorporate the auto brake feature of most modern systems.
[Edited on 23/5/12 by coyoteboy]
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scootz
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| posted on 23/5/12 at 02:53 PM |
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I've always been tempted to try and fiddle with some sort of linear-atuator for the trike. A simple switch would save me the hassle of trying
to cram a lever in the cockpit.
Surely it wouldn't have to produce much force to pull a single spot-caliper suitably tight on the rear disc of a 300kg vehicle???
It's Evolution Baby!
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hughpinder
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| posted on 23/5/12 at 03:06 PM |
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The main problems I have with electric handbrake on tintops are:
1. If it fails its almost certainly return to dealer - how if its 'on'?. In the good old days when I ran cars from the 60/70s the
handbrake mechanism might seize, but you could almost always sort it for next to nothing rather than 'its the ECU mate, that £600' or the
dedicated controller box or the caliper. It almost certainly means taking the car to the main dealer when the pads need sorting too if you need a
special ecu mode to back the pads out(=£120 rather than £30).
2.My wife actually runs a fleet of cars. electronic failures are the most common fault by a long way, especially if its french. In my experience they
are the problems that are the most difficult to overcome at home, unless you are lucky and spot an obvious break in the wire or fallen off
connector.
3.A lingering fear that the brake will suddenly apply itself, or release itself. At my missus's they have had one car roll away in the carpark
(luckily its very shallow slope so no damage was done)
when the auto handbrake was active (Audi).
Regards
Hugh
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scootz
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| posted on 23/5/12 at 03:12 PM |
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almost man enough actuator linky... but not quite
It's Evolution Baby!
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JeffHs
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| posted on 23/5/12 at 03:25 PM |
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Toyota uses electric park brake and everyone knows Toyotas don't break down!!!!
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macc man
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| posted on 23/5/12 at 03:25 PM |
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It seems to be the trend over the last ten years to overcomplicate everything to force motorists into the dealers clutches to be robbed blind. Soon
there will be nothing that is customer servicable on a car. Fine if its a firms car, but what about the average joe who gets fleeced every time it
goes wrong. Keep things simple in my view.
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dhutch
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| posted on 23/5/12 at 03:31 PM |
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quote:
Originally posted by coyoteboy
A lever, ratchet, pair of cables, associated mounting points, associated lifespan of lubes, potential adjustment requirements etc are nowhere near as
simple as a switch, wire and a box of gubbins with some software to deal with control of the caliper?
Depends whats in the box of gubbins. In my experience said boxes are rairly cheap.
Electronics is great for somethings, no one would go back to mechanical points for instance, or carburetors, but handbrake cables are buttons, as im
sure are the leavers which are just a bend bit of 3mm laser cut sheet.
Daniel
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coyoteboy
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| posted on 23/5/12 at 03:32 PM |
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Certainly a lot of cars these days are having electrical faults but IME they're nothing you can't fix if you have a bit of electronics
knowledge, just like mechanical issues for people with mechanical knowledge. The equivalent of a rattle in a track rod end. Sometimes there's
major failures of whole components, these seem to be catastrophic (Large ECU failure) which will happen when you have millions produced, it's
just the laws of averages, most of the mechanical parts have had 50 years of knowledge put in to them. All the faults I've seen on french cars
are wire failures, that's due to poor design and poor materials for a cheaper car. And if you don't have to go to a dealer for the part,
it doesn't cost hundreds. But valid points all the same.
A locost setup of this sort would not require ECU diags to retract for pad changes, that's been specifically designed in for a reason.
As for accidental applications or removals - the former should be designed out of the electronics, the latter - that's a bit more complex as it
relies on sensing when enough force has been put on. I've never heard of one doing that TBH but I'd have to know the circumstances to give
a fair assessment.
quote:
Depends whats in the box of gubbins. In my experience said boxes are rairly cheap.
Build, don't buy But I guess for your average punter that is a bit harder than attaching cables. But I never said this was everyones cup of
tea.
[Edited on 23/5/12 by coyoteboy]
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adithorp
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| posted on 23/5/12 at 03:39 PM |
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rather than mess about with the electronic controls of VAG why not use the electro-mechanical systems as found on Jag S-types etc. Standard cable
h/brake calipers with an electric motor pulling the cable and simple switching.
Still prefer the control of a manual lever though.
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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mcerd1
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| posted on 23/5/12 at 03:57 PM |
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quote:
Originally posted by coyoteboy
A lever, ratchet, pair of cables, associated mounting points, associated lifespan of lubes, potential adjustment requirements etc are nowhere near as
simple as a switch, wire and a box of gubbins with some software to deal with control of the caliper? I think the locost brethren are still in an era
where electronics are a black art and a failure point
...or put another way, a few mechanical parts that are easy to inspect and maintain with
basic tools and minimal knowledge
vs a handful of wires and a black box that you either throw away and replace (at a considerable cost) or need specalist tools and a knowledge of
electronics to fix.....
quote:
I'm considering buying a VAG caliper just to check out the interface - it won't be complex for a tiny micropro box. And the
combined weights of all parts are likely to be very similar.
I know several people that have had issues with the newer VAG calipers, either the
electronics packing in or the caliper siezing up (admitedly these cars had done 70k+)
quote:
quote:
If they got rid of all this crap then modern cars would hardly go wrong!!!!
Personally I've had 3 handbrake cables snap, one caliper seize on and replaced 2 other cables due to lube breakdown as they got higher milage.
They almost always need adjustment for MOT man to be happy. Couple of wires and a switch sounds like heaven to me.
I'm afraid I'm
with fazerruss on this one, I recon cars peaked sometime in the 90's (ok not all models, but the best of them), when they just figured out how
to stop them rusting in 5min, but before they had electric/electronic everything
e.g. my wee k reg carb'd 106 was near bomb proof even after 100k abd 15years - the only breakdown I ever had was the ignition amp, the only
electronic bit on the car! (I will admit that its handbrake was s***, but that was a tiny wee drum setup)
I've never had a cable snap or seize and I've always had old higher milage cars, and a clean up, check and adjustment once a year is
hardly the end of the world
besides electronic or not you sould really be checking them to make sure they arn't seized or leaking break fluid !
quote:
.....I understand that the ECU has to be controlled to wind the brakes out to change the pads, so perhaps it is a little more complicated than
locost.
I'm told that you can just take the motor off wind them back by hand with an allen key/torx bit (then the ECU re-sets itself when
you start it up again  )
for the record I'm not some old fart set in his ways (well not that old anyway, I was born in the 80's)
I don't like electonics much, but play around with odd things (MJ for the dax, home built pc's etc...) - but I just don't see the
need for an eletronic hand brake if the mechanical one is an easy option
just my 2p's worth......
[Edited on 23/5/2012 by mcerd1]
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coyoteboy
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| posted on 23/5/12 at 04:15 PM |
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quote:
rather than mess about with the electronic controls of VAG why not use the electro-mechanical systems as found on Jag S-types etc. Standard cable
h/brake calipers with an electric motor pulling the cable and simple switching. Still prefer the control of a manual lever though.
This is exactly the same arrangement though, only the electronics (or rather electricals) are concentrated into one unit instead of two. All the VAG
calipers contain are an electric motor, gearing to the back of the piston and a latching pin that prevents the caliper backing off when the power is
removed. It's possibly the most simple electromechanical device you ever saw. In order to move the caliper you raise the pin, power the motor,
watch until motor current hits a certain level telling you it's hit home, then re-latch. Sure the gubbins to control that are held elsewhere on
the normal vehicle but thats because it's easier to incorporate that into another control unit and for the sake of anti-roll-back operation may
need input from elsewhere. You could control the caliper electronics via a couple of relays and switches in its rawest form.
Here's a diagram of a similar one:
quote:
handful of wires and a black box that you either throw away and replace (at a considerable cost) or need specalist tools and a knowledge of
electronics to fix.....
Unless you have total breakdown of the main control unit electronic failures are just as easy to find as mechanical ones. Just the same way
you'd not try to replace a crankshaft without a torque wrench, you don't try to diagnose the electronics without a simple scope and DMM.
Neither are cheap, but neither is a decent set of mech tools.
quote:
I know several people that have had issues with the newer VAG calipers, either the electronics packing in or the caliper siezing up (admitedly these
cars had done 70k+)
At 70K that doesn't surprise but again, strip the calipers yourself and you'll see how easy they are to service/maintain. Only issue being
lack of replacement sub-components which I'll give you
quote:
I don't like electonics much, but play around with odd things (MJ for the dax, home built pc's etc...) - but I just don't see the
need for an eletronic hand brake if the mechanical one is an easy option
Fair enough, it's personal choice. However I've never once argued against mechanical handbrakes, I was just trying to provide people with
some info in case they want to go that way, somewhere down the line it became people telling me it wasn't the way forward However I love
electronics and mechanical stuff (combining them is my career field!) so I'm not shy of trying this sort of thing.
[Edited on 23/5/12 by coyoteboy]
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perksy
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| posted on 23/5/12 at 04:17 PM |
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Sorry, Really don't see the need for an electric handbrake
More to go wrong and over complicated
We've been managing fine with cable operation for years so why re-invent the wheel ?
Mate had one on his Renault and absolutely hated the thing, it kept getting stuck and it was one of the main reasons
he got rid of it in the end
Each to his own though
[Edited on 23/5/12 by perksy]
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coyoteboy
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| posted on 23/5/12 at 04:24 PM |
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Dear christ, if you're just going to bash it at least read the thread and realise what you've said has been said before.  I'm not
asking for opinions, I'm offering info.
If you're building a mid-rear engined car with shift gubbins going backwards, a tunnel fuel tank and fully IRS rear end removing a bunch of
unpleasant looking and pesky cables is actually fairly handy.
[Edited on 23/5/12 by coyoteboy]
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jacko
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| posted on 23/5/12 at 04:30 PM |
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I have a new vauxhall Astra with a electric hand brake [ i hate it ] and i don't trust it
I wish the car had the old fashioned cable brake
Jacko
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MikeRJ
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| posted on 23/5/12 at 04:52 PM |
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quote:
Originally posted by coyoteboy
This is exactly the same arrangement though, only the electronics (or rather electricals) are concentrated into one unit instead of two. All the VAG
calipers contain are an electric motor, gearing to the back of the piston and a latching pin that prevents the caliper backing off when the power is
removed. It's possibly the most simple electromechanical device you ever saw.
So you have an electric motor and associated gearing in a lump of metal that can get smoking hot under hard use, and which also should be make as
light as possible? That doesn't seem like a clever idea.
There doesn't appear to be any difference in the construction of the sliders and the piston, so what makes you think these electric calipers
will be less prone to seizing than normal cable operated ones?
I'm firmly against electrically operated brakes; there is simply no way on gods earth they are going to be as reliable as the very simple
mechanical linkage in cable operated calipers, and they are less than useful as an emergency brake in the event of a hydraulic failure.
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scudderfish
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| posted on 23/5/12 at 05:15 PM |
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I'm quite tempted to fit one to my Fury. The lever is currently in an awkward place and takes space away from an already cramped passenger.
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coyoteboy
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| posted on 23/5/12 at 06:33 PM |
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quote:
Originally posted by MikeRJ
So you have an electric motor and associated gearing in a lump of metal that can get smoking hot under hard use, and which also should be mak[e as
light as possible? That doesn't seem like a clever idea.
They are designed to deal with 200c happily and they are distal to the heat source. Yep a bit heavier.
quote:
There doesn't appear to be any difference in the construction of the sliders and the piston, so what makes you think these electric calipers
will be less prone to seizing than normal cable operated ones?
I never said it was less susceptible to seizing?
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whitestu
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| posted on 23/5/12 at 06:44 PM |
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Nobody is addressing the main issue and sole purpose of existence of handbrakes.
Can you do handbrake turns with them?
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Hector.Brocklebank
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 posted on 23/5/12 at 08:17 PM |
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quote:
Originally posted by whitestu
Nobody is addressing the main issue and sole purpose of existence of handbrakes.
Can you do handbrake turns with them?
Some people can never handle the truth and always try to shoot the messenger instead of taking an honest look in the mirror (its always easier to
blame another than to face reality), but secretly they wish they could grow a pair and be the messenger !!!
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Hector.Brocklebank
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| posted on 23/5/12 at 08:18 PM |
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quote:
Originally posted by whitestu
Nobody is addressing the main issue and sole purpose of existence of handbrakes.
Can you do handbrake turns with them?
Some people can never handle the truth and always try to shoot the messenger instead of taking an honest look in the mirror (its always easier to
blame another than to face reality), but secretly they wish they could grow a pair and be the messenger !!!
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