Just passing on an experience following yesterdays drive to the Southern meet.

Had been travelling on the motorway for many miles in prolonged spray and heavy rain fall, came off at a service station and needed to brake a little bit more than that need to control the speed for the exit to turn in the parking area for cars that I had missed the sign - and then experienced a greaty reduced braking efficiency to normal it was lucky I wasn't using them for an emergency stop or top scrub speed off whilst I was driving on the wet motorway at speed.

Talking to "mellowyellow" unprompted he experienced the same problem as this whist braking to change lanes to leave at a motorway exit. I have driven in this sort of heavy rain fall in my other Octavia and never experienced the problem.

Its a warning to me that I know that this problem will happen again if driving in this sort of weather.

It reminded me of a problem I seem to remember the Audi A4's had on long wet drives, which was found to be caused by a build up of water and road salt between disc and pad :quote:

"Following initial investigations by Audi's technical experts, whose

findings were confirmed by ADAC experts, it is suspected that new types

of road salt, in particular magnesium chloride used in a technique known

as "wet salting", affects the friction between the brake disc and the

brake pad."

the experience seemed very similar. - At a longshot maybe the motorway had been excessivly salted after the dropoff the previous week when the snow froze??

Just a warning to other drivers to be aware, I am sure we all are sensible drivers who leave extended gaps during wet weather - but its still very scary when it happens even when you have nothing to hit.

Any one else experienced this condition? and if so when and what time of year?

This isn't simply a case of reduced braking efficiency due to the brakes becoming saturated then - as occurs after driving through a ford, for instance?

Denis,

Know what you mean about driving through a ford and getting the brakes saturated and I am always very careful to test afterwards - and always apply the brakes after driving through large puddles etc.

But this experience yesterday was very unusual - we all learn by our experiences and luckily didn't need the brakes to avoid an impact, it was wet but have driven in much harder and prologed rain on the continent in other cars but never ever experienced anything like it - perhaps mellowyellow will mail his experience.

I guess he was surprised also as he commented to me, and we both have I would assume quite a few years driving experience in all sorts of weather and cars and will adapt driving technique accordingly.

John ,

Yes , I was surprised at the time as to the lack of brakes , but in hindsight about 1/2 mile before that we went through a dip in the road with quite a lot of standing water , that coupled with all the water on the road anyway would probably explain it. You stated that you always test the brakes after driving through large puddles of water , but that's difficult to do on a motorway without causing panic behind you . Another factor could be the fact that the brakes on the RS are so good , that if just slowing down you wouldn't expect to have to apply much pressure . Anyway it is something I will remember the next time I'm driving in those sort of conditions .

Just passing on an experience following yesterdays drive to the Southern meet.

Had been travelling on the motorway for many miles in prolonged spray and heavy rain fall' date=' came off at a service station and needed to brake a little bit more than that need to control the speed for the exit to turn in the parking area for cars that I had missed the sign - and then experienced a greaty reduced braking efficiency to normal it was lucky I wasn't using them for an emergency stop or top scrub speed off whilst I was driving on the wet motorway at speed.

Talking to "mellowyellow" unprompted he experienced the same problem as this whist braking to change lanes to leave at a motorway exit. I have driven in this sort of heavy rain fall in my other Octavia and never experienced the problem.

Its a warning to me that I know that this problem will happen again if driving in this sort of weather.

It reminded me of a problem I seem to remember the Audi A4's had on long wet drives, which was found to be caused by a build up of water and road salt between disc and pad :quote:

"Following initial investigations by Audi's technical experts, whose

findings were confirmed by ADAC experts, it is suspected that new types

of road salt, in particular magnesium chloride used in a technique known

as "wet salting", affects the friction between the brake disc and the

brake pad."

the experience seemed very similar. - At a longshot maybe the motorway had been excessivly salted after the dropoff the previous week when the snow froze??

Just a warning to other drivers to be aware, I am sure we all are sensible drivers who leave extended gaps during wet weather - but its still very scary when it happens even when you have nothing to hit.

Any one else experienced this condition? and if so when and what time of year?[/quote']

The same problem has been reported on VW Passats and I have seen the problem posted more than once on tdiclub.

My dad has a passat and he is extra careful when braking on motorway slip roads after long spells of wet weather driving.

Road salt or poor design i dont know.. It can happen at any time of year.

The same problem has been reported on VW Passats and I have seen the problem posted more than once on tdiclub.

My dad has a passat and he is extra careful when braking on motorway slip roads after long spells of wet weather driving.

Road salt or poor design i dont know.. It can happen at any time of year.

A Friend of mine experienced this on this Passat only the once and it was during winter motorway driving - again once when you know it can happen you can adjust technique, we are all a bit to comfortable and lulled into a sense of security in our driving machines and forget problems can be experienced that we need to react to rather than the vehicle gizzmo's.

Stopan1j Wrote

we are all a bit to comfortable and lulled into a sense of security in our driving machines

John , I think that could be the answer .

Yep, the same goes for fast bikes but more so. Bikes stop on a sixpence in the dry but if you are riding in heavy rain there is a build-up of water that needs to be removed before they start working efficiently, and that is a frightening experience!

The best technique I found is to lightly brake a full two seconds early before you would normally brake and this allows the water to be removed. In the case of the car 2 seconds is probably a bit excessive but it is something I tend to do out of habit, hence I have never been caught out, or at least not yet.

Mike

Thanks for your comments and am sure there is is no "problem" with the brakes on the car.

It may be that the RS may be more susceptible than other vehicles due to a number of reasons as in all accidents - just my thoughts:

1. Clearance between outer edge of caliper to inner of wheel is quite large on the RS so may be more affected by spray etc?

2. The area of the alloy whel is larger and quite open with the pattern of the wheel so can have more water ponded at teh braking area components.

3. With low profile tyres fitted water is more likely to reach the caliper disks ?

4. The brakes being normally so good a degregation is very noticable.

5. The nature of the vehicle means that drivers accelerate harder and brake harder than in more normal cars - so the effects of water on the brakes is more evident

Any one remember fitting racing black blocks to a standard pushbike? - the braking was excellent in the dry - but non existent in the wet - always amazed me. :?

I've noticed the same sort of thing once or twice recently, so it's not just vRS's that are affected. Conditions have been similar (long motorway runs in rain/spray, at or near freezing temperatures).

I've a sneaking suspicion that it's (partly) down to driving style; if you're driving smoothly you probably won't need to touch the brakes from the time you join the motorway to the time you leave it. This gives the spray plenty of time to soak into the brake pads, and build up a film of gunge on the discs.

Been there done that

exactly the same thing happened to me .

Although i must say now i have changed the pads havent felt it recently maybe test it this weekend on my journey to bath for golf.

Its bound to be raining and cold

I have also experienced this and this is nothing unique for the RS! Lots of cars have the same problem. One way to avoid this is to get drilled or grooved rotors. That way the water has no way of building up the thin layer of water causing this sudden loss of brake efficiency. Mercedes have in a clever way solved this problem on the latest S-klass by having the brakes applying every now and then automatically when raining. The brake pressure is so light that it isn't noticable for the driver but still enough to keep the rotors dry.

Mercedes have in a clever way solved this problem on the latest S-klass by having the brakes applying every now and then automatically when raining.

Must remember to exercise even more caution when following any Mercedes at speed on wet motorway just in case the

automatikbrakewipesystemfordispersingextrawater (the German language is full of incredibly long technical terms) malfunctions!

The Audi reference to 'wet salting' is interesting. I'd never heard of this before the other week when someone posted after seeing it done to clear the bad conditions you 'down south' experienced. Is it possible you were in the same area?

I have found that after washing the wheels and I now use a brush and lots of water to try to get the inner rims clean and those green calipers that the brakes are very poor until going a few yards or a second application. They also look and sound "rough" i.e rust forming and I'm sure thats what is happening on the motorway only to a lesser extent due to centrifugal force.

Chris

Thanks for your comments and am sure there is is no "problem" with the brakes on the car.

It may be that the RS may be more susceptible than other vehicles due to a number of reasons as in all accidents - just my thoughts:

1. Clearance between outer edge of caliper to inner of wheel is quite large on the RS so may be more affected by spray etc?

2. The area of the alloy whel is larger and quite open with the pattern of the wheel so can have more water ponded at teh braking area components.

3. With low profile tyres fitted water is more likely to reach the caliper disks ?

4. The brakes being normally so good a degregation is very noticable.

5. The nature of the vehicle means that drivers accelerate harder and brake harder than in more normal cars - so the effects of water on the brakes is more evident

Any one remember fitting racing black blocks to a standard pushbike? - the braking was excellent in the dry - but non existent in the wet - always amazed me. :?

Otka's do it all the time.

Even when dry. After say 30 miles of a19 to Miss L's house I hit the brakes on a cold night (First time on the brakes for 30 miles) and they are very poor.

But I simply do not care...

The Merc s-class with its auto braking, sounds like a good way for the manufacturers to get more money out of you come service time when they inform you that those brakes need replacing at an amount per corner that would make Bill Gates blush!

Who says I am sinical?

Damo