electronic handbrakes

[tjamesbo]

What was wrong with a parking brake lever acting on a couple of cheap cables which in turn acted on either brake shoes or callipers?

The photo above is of the internal workings of an electronic parking brake (EPB) assembly on a 2005 Renault Scenic. The cable from the EPB to the rear right brake calliper had seized and the exposed inner cable at the calliper end had frayed. This cable, although removable isn’t available separately so the entire EPB assembly needs replacing and to top it off a new component needs reprogramming/recoding. A rough estimate for all of this is in excess of £500.
That’s a big price to pay because we’d rather press a button than pull a lever to apply the handbrake!
Courtesy of a Mechanics Blog

 

[jaymanek]

Totally agree a totally pointless innovation. We replaced one on an s class and the bill was 1400. Totally nuts!

 

[Meldrew2]

It's the price of convenience.

How much is it to replace a power steering system - yet we wouldn't be without it.

Same goes for central locking, window motors, air conditioning, etc.

I bet a long time ago someone even asked "what's wrong with a starting handle?"

 

[jaymanek]

It's the price of convenience. How much is it to replace a power steering system - yet we wouldn't be without it. Same goes for central locking, window motors, air conditioning, etc. I bet a long time ago someone even asked "what's wrong with a starting handle?"

Not the same. There are some systems that simply replace the lever which are ok, the systems that are completely electronic with motors on the calipers are simply unreliable.

I don't really see that electronic handbrakes are any more convenient than a standard one.

 

[V12]

Can't believe he'd rather pay £500 than get a custom cable made up...

 

[grober]

Spawn of the devil! An electro-mechanical complication whose potential ability to strand the car owner far outweighs any extra utility it may convey. At least on some systems like the Renault the actuators are sheltered by some extent from the worst effects of road grit, water saturation and heat unlike the motorised caliper versions - they are a failure just waiting to happen. Expect more of this sillyness from Mercedes with the new W205-- C class and all new A class derived models CLA and GLK. One horror story I heard was of a new Jaguar XF ----- one year down the line with multiple assemblies replaced under warranty the owner still doesn't know from one day to the next if he is going to be stranded with a seized parking brake waiting for the tow truck. Apparently its "an intermittent electronics problem" they can't quite pin down.

 

[Meldrew2]

I don't really see that electronic handbrakes are any more convenient than a standard one.

I've never used the handbrake in either of my MB. The foot pedal is awkward and hurts my knee - a bad left knee is the main reason I drive automatics. An electrically operated brake would be easier for me - but I just use "P"

My ex wife had a scenic - she loved the electronic brake, because it disengaged automatically when pulling away - so hill starts were a lot easier for her. Then again, learning clutch control would have been an idea……..

 

[poormansporsche]

I remember a while back talking to a service manager at VW when the Passat B6 came out - one of the first mainstream models to have a electric handbrake and he told me that 95 % of faults and returns in the first 3 months when the car came out were due to the electric handbrake !

 

[Peter T]

Appart from the stupidity of something so complex to perform such a simple function, that handbrake assembly looks fairly heavy to me.

I thought the idea these days was to reduce weight wherever possible!

 

[Meldrew2]

I remember a while back talking to a service manager at VW when the Passat B6 came out - one of the first mainstream models to have a electric handbrake and he told me that 95 % of faults and returns in the first 3 months when the car came out were due to the electric handbrake !

That's fairly typical of new innovations - but they get refined and improved over the years. Remember early radio key fobs, central locking and alarms? Now there's hardly a car without them. Audi's procon-ten seatbelts were unique - and complicated - but now we expect seatbelt pre-tensioners on every car. Fuel injection was also troublesome in early years - but now you can't find a car with a carburettor!

Eventually, technology becomes so reliable and easy to use that we start to wonder how we managed without them.

 

[BTB 500]

A year or two back I listened to a guy on the train telling his friend about how he got run over by his Renault. It was parked on his sloping drive and he was trying to do something inside the boot (release the spare possibly?). Anyway he pressed a button there that turned out to be a release for the electric handbrake. Car rolled back, he was dragged underneath it out into the road until it hit the kerb on the other side. Had some crush injuries to his chest plus obvious abrasions etc.

 

[grober]

That's fairly typical of new innovations - but they get refined and improved over the years. Remember early radio key fobs, central locking and alarms? Now there's hardly a car without them. Audi's procon-ten seatbelts were unique - and complicated - but now we expect seatbelt pre-tensioners on every car. Fuel injection was also troublesome in early years - but now you can't find a car with a carburettor!

Eventually, technology becomes so reliable and easy to use that we start to wonder how we managed without them.

I expect on that basis they will have the road spring breakage thing sorted out by now then?

REPLACEMENT COST approx ----worst case scenario

W169
3 CABLES £60 total +labour at local garage rates.

W172
2 ACTUATORS+ CONTROL UNIT £400+ labour + coding at MB dealer rates.

That's probably a factor of 5+ in repair costs

Seems a high price to pay for pushing a button rather than pulling a lever?

 

[Major774]

On the W211... SBC Hold... awesome for hill starts.

 

[tjamesbo]

I suspect the reason for the proliferation of gadgets is they look good on a new car and help sales but also have tremendous aftermarket earning potential in labour and parts when they go wrong a lot of cars are produced and sold at break even , profit is made on spares / replacements. Nice little earners.
if it goes wrong in the first few years the Company car owner doesnt care about the cost its a license to print the £££££.
After all if we just had a modern ford cortina now it would / should ?? be so reliable by now that no one would make anything from it .Folks and the young today tend to buy wholly on image / affordability, not many consult reliability sources or think about what happens / cost when it goes wrong
Boyd

 

[tjamesbo]

On the W211... SBC Hold... awesome for hill starts.

Is it a manual then???? never had any problems with a hill start on any of my Autos
I can see the benefit on a manual with the foot operated handbrake
am I missing something?

 

[jamesfuller]

I cant understand the point of it. My mates Disco just had it all replaced, Not far off a grand!
Replacing a simple mechanical system for no good reason, I suppose one manufacturer decided to do it and the others thought they should just keep up with them!

It's the price of convenience.

How much is it to replace a power steering system - yet we wouldn't be without it.

Same goes for central locking, window motors, air conditioning, etc.

I bet a long time ago someone even asked "what's wrong with a starting handle?"

It probably would cost a lot to replace any of these systems, but have you actually had too? I've owned 50, maybe 60 cars and I think 3 windows have stopped working and a stone went through the condenser on one! Central locking packed up once but just used the key. They are still fairly simple systems.

I don't have a problem not having power steering, auto box, don't even mind sliding a window open (usually just have to keep sliding them shut as they creep) But it is rather nice and easy to get used to.

A starting handle, I see that as a luxury if the vehicle is fully loaded and develops a charging fault! makes checking the points a bit easier and you don't need to carry starter spares! Of course in this country you are never far enough away from anywhere for this to really be an issue!

I am all for luxuries but I like simple luxury, the reason I like W126's. Making something needlessly complicated just for the sake of it is just a gimmick that will see many modern cars unsustainable soon after being out of warranty.

I still think in general mid to late 90's cars where just about the best of everything, nearly catching up with the 80's Mercs in some cases!

 

[grober]

Most modern mercedes have a HOLD facility on the main braking system. Come to a halt ---tap the brake pedal twice ---- the HOLD symbol appears in the cluster and the brakes are applied. To move off either-- tap the brake pedal again--- or press the accelerator and the brakes are released as the car pulls away. The handbrake mechanism is not involved in any way. [ the handbrake is cable operated in the W204 C class anyway] So while an automatically releasing electronic handbrake might be useful for hill starts in some manual cars that facet is largely redundant in modern MERCS possessing brake systems with a HOLD facility. Ironically if you do engage the manual handbrake the HOLD facility doesn't work irrc

 

[def90cars]

Remember the old days when you used a pen and wrote to friends..... none of this new fangled "computer" stuff with all it parts and going wrong all the time!! (ZX81s!)
A computer is £500... a pen and stamp barely £1!

 

[prprandall51]

Most modern mercedes have a HOLD facility on the main braking system. Come to a halt ---tap the brake pedal twice ---- the HOLD symbol appears in the cluster and the brakes are applied. The rear brake lights dazzle the poor driver parked up behind you in the queue until the lights change - especially on a dark, rainy night - but it's easier than using the parking brake so what the hell. To move off either-- tap the brake pedal again--- or press the accelerator and the brakes are released as the car pulls away. The handbrake mechanism is not involved in any way. [ the handbrake is cable operated in the W204 C class anyway] So while an automatically releasing electronic handbrake might be useful for hill starts in some manual cars that facet is largely redundant in modern MERCS possessing brake systems with a HOLD facility. Ironically if you do engage the manual handbrake the HOLD facility doesn't work irrc

Corrected that for you.