Volkswagen nightmare

renzotiger

I appreciate its difficult for a mechanic/technician to get to the root of an intermittent fault, but what do i do if they cant replicate the fault?

renzotiger

And if the onboard computer is clever enough to log a fault with any part of the braking system, surely there should be a precautionary indication on the dash to alert the driver?

gilbert_and_sullivan

renzotiger wrote: »

I wouldnt class myself as an incompetent driver, im just using the technology the manufacturer has installed. It was autohold, it doesnt have a hill hold. I think cars are one or the other these days.

Fault 3 the engine was running, i was reducing from about 35mph over a distance of about 50m. I could see the stationary car at the bottom of the hill

I wasn't suggesting you were and am sorry if my post suggested that, its just that these gimmicks are there to take away the need for a driver to control their cars, they are sold to people who can't do hill starts for goodness sake, so instead of actually learning to control their cars they don't need to after all, utopia.

Electric parking brake and hill/auto hold (i'd have thought hill/auto the same thing really), wonderful you stop switch off and bale out relying completely on the car to do it for you because it always does, until one day it doesn't, you're 10 yards away as you've done for the past 2000 stops and the car's off down the road.

Still sounds like a servo fault to me in scene 3, had you pumped the brakes repeatedly on the descent, which i suppose could with a Diesel on low revs empty the vacuum reserve faster than the pump could replenish it, try it for yourself stationary and see how long it takes for the vacuum to go, you'll feel it in the pedal when its no longer assisted...with the engine running on tickover you should not be able to beat the pump unless you operate the brake pedal at a really fast rate, if you can easily beat it then that points to a poor vacuum pump...unless your car is petrol in which case it possibly doesn't have a pump, might be natural intake vacuum fed.

Agree that a brake fault should show up, but they can't even manage a single bulb illuminating to tell you of the state of DPF regen, so wouldn't hold your breath while they put anything genuinely useful up on the display.

renzotiger

gilbert_and_sullivan wrote: »

I wasn't suggesting you were and am sorry if my post suggested that, its just that these gimmicks are there to take away the need for a driver to control their cars, they are sold to people who can't do hill starts for goodness sake, so instead of actually learning to control their cars they don't need to after all, utopia.

Electric parking brake and hill/auto hold (i'd have thought hill/auto the same thing really), wonderful you stop switch off and bale out relying completely on the car to do it for you because it always does, until one day it doesn't, you're 10 yards away as you've done for the past 2000 stops and the car's off down the road.

Still sounds like a servo fault to me in scene 3, had you pumped the brakes repeatedly on the descent, which i suppose could with a Diesel on low revs empty the vacuum reserve faster than the pump could replenish it, try it for yourself stationary and see how long it takes for the vacuum to go, you'll feel it in the pedal when its no longer assisted...with the engine running on tickover you should not be able to beat the pump unless you operate the brake pedal at a really fast rate, if you can easily beat it then that points to a poor vacuum pump...unless your car is petrol in which case it possibly doesn't have a pump, might be natural intake vacuum fed.

Agree that a brake fault should show up, but they can't even manage a single bulb illuminating to tell you of the state of DPF regen, so wouldn't hold your breath while they put anything genuinely useful up on the display.

No worries mate, i didnt take offence. The technology is only going to progress, its here to stay whether we like it or not.

Hill hold only gives you 3s of brake so that, like you say, you can easily accelerate away from a hill. Autohold is a permanent brake, when the car is stationary, its for traffic lights and junctions. I expect the reasoning behind it is so that you can take yiur foot off the footbrake without applying the handbrake in order not to dazzle drivers stuck behind you at night. A handbrake for short periods.

The car has been into the garage and funnily enough, the brake pedal does feel a lot "tighter" than when it went in

gilbert_and_sullivan

Yes electric parking brakes now finding their way onto artics, what could possibly go wrong :whistle:, auto hill hold/temp hold i turn off soon as i get in a lorry, i'm in control ta and it'll stay like that as long as i'm in the job.

Oh and adaptive cruise and lane departure and automatic braking, the future is bright indeed , but luckily i'll be retired soon and they can put whatever gimmicks in they want, when the drivers are deskilled enough they'll have to have another think.

renzotiger

Seen article today, 100 autonomous Vilvos are being trialed on the roads of Sweden next year!!! Hill hold's the least of our worries hahaha!

zoolando

I have a 63 plate 2.0TDI Golf with auto hold. I am pretty sure the brake lights stay on while on auto hold.

For Fault 2 - one thing I have noticed is that if you press the brake pedal and gently tap the accelerator (so pressing both pedals), auto hold is released. I usually use this method when coasting down hill in traffic while the car is in auto start/stop however you have to roll extremely slowly to not start the engine. I wouldn't say this is a fault, more of a quirk! I wouldn't lean over to the passenger side without having handbrake on or foot covering the brake.

For Fault 3 - that really doesn't sound good however the distance required to stop at 40mph is about 36m including thinking and braking distance. As you were doing 35mph, lets say you could stop in 30m. You were going down hill however so the gradient will increase your stopping distance to a degree. Lets say that is another 5m. It sounds like you were on a dry road as usually anti lock brakes would kick in wet braking hard. Have your front tyres been replaced yet? Mine were done at 18k and grip was noticeably better after.

renzotiger

zoolando wrote: »

I have a 63 plate 2.0TDI Golf with auto hold. I am pretty sure the brake lights stay on while on auto hold.

For Fault 2 - one thing I have noticed is that if you press the brake pedal and gently tap the accelerator (so pressing both pedals), auto hold is released. I usually use this method when coasting down hill in traffic while the car is in auto start/stop however you have to roll extremely slowly to not start the engine. I wouldn't say this is a fault, more of a quirk! I wouldn't lean over to the passenger side without having handbrake on or foot covering the brake.

For Fault 3 - that really doesn't sound good however the distance required to stop at 40mph is about 36m including thinking and braking distance. As you were doing 35mph, lets say you could stop in 30m. You were going down hill however so the gradient will increase your stopping distance to a degree. Lets say that is another 5m. It sounds like you were on a dry road as usually anti lock brakes would kick in wet braking hard. Have your front tyres been replaced yet? Mine were done at 18k and grip was noticeably better after.

I have no idea whether the brake lights remain on or not with autohold, It was only a thought.

I always reach over to the passengers seat on autohold, it's within arms reach. I do it twice a day. Autohold will release if the accelerator is touched or clutch released, this wasn't the case. I'm convinced the fault found (and stored) in December on the autohold is the reason this happened. Like I said before, an onboard computer which can detect and store a fault with part of a braking system that doesn't alert the driver is something which I think needs addressed.

Front tyres have t been changed but still above the legal limit. Weather conditions were good. The road has good grip as its notorious in the wintry weather. I've driven that car down that same hill everyday home from workforce nearly 18 months, it's a blind junction at the bottom, I know I have to stop, I decelerated at the right time, it wasn't misjudgement. The problem was the brakes, they weren't as responsive as they should have been given the pressure I was applying. I only slightly bumped the car at the bottom of the hill but there was no visual or audible warning from the dash. No skid and wheels still turning while full pressure applied to the foot brake.

thescouselander

Fault 3 sounds like contaminated brake fluid. If it absorbs too much water the boiling point gets very much lower and the fluid can book off during braking causing the symptoms you described. It's probably worth getting it changed just in case.

renzotiger

thescouselander wrote: »

Fault 3 sounds like contaminated brake fluid. If it absorbs too much water the boiling point gets very much lower and the fluid can book off during braking causing the symptoms you described. It's probably worth getting it changed just in case.

Thanks mate, what could cause it to absorb too much water? The car has been back to the garage and they say they can find no fault (as you would expect them to do). Funny old thing, my brakes feel a bit "tighter" from the pedal since they've been in so they've definitely made some adjustments somewhere.