Renault Scenic Hissing from under Brake

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Thu 30 Oct 2003 20:35
Renault Scenic Hissing from under Brake - Renault man
Hi folks,

I wonder if anybody can help me. Two weeks ago I noticed a slight hiss whilst driving my 2002 Scenic 1.9D. Over time it got louder, so I popped my head down to where the noise was coming from. I discovered a set of Bellows mounted behind the Brake pedal, had a gentle fiddle and was satisfied that the Bellows were leaking.
Interestingly enough Renault Workshop claim that it is the Servo unit that is at fault and requires replacement and could take around 5 hours. On this basis they will not release the vehicle as it is considered unsafe.
I'm not certain that I had been told the truth and wondered whether somebody out there could advise me.

Kevin
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Fri 31 Oct 2003 08:20
Renault Scenic Hissing from under Brake - Aprilia
Yes, it sounds like the servo is leaking. Servo unit are not considered repairable and are swapped-out as a sealed unit. I think they are telling you the truth. Presumably it is a warranty repair anyway.
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Fri 31 Oct 2003 09:24
Renault Scenic Hissing from under Brake - Ivor E Tower
There is a recall for diesel Scenic brake "servos" - note that with a diesel there is no inlet manifold vacuum to provide a true servo - you actually have a brake booster.
Check with your dealer that this is a warrantly or recall item - they should be able to tell you by accessing Renault's technical database with your car's VIN number.
My scenic was recalled a few years back for this item (and others - lost count now of how many recalls it's had). The letter I received said I should go to the dealer for a quick precautionary check, and they then told me that "really you shouldn't be driving the car" - so much for the "nothing to worry about" note in the recall information letter!
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Fri 31 Oct 2003 09:30
Renault Scenic Hissing from under Brake - David Horn
They won't release it? They have absolutely no right to hold on to the car if you want to take it home. Even if the worst comes to the worst, the car is still perfectly drivable with a complete servo failure. It happened to my dad's and he drove it to the garage 40 miles away - braking efficiency wasn't reduced but he had to push a damn sight harder on the pedal.
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Fri 31 Oct 2003 12:07
Renault Scenic Hissing from under Brake - Altea Ego
David I am sorry to be so blunt but your post is complete twaddle and dangerous advice to boot.

The Renault Garage would be failing in their duty if they allowed a customer to drive home after diagnosing a serious braking problem. They have every right, in fact a LEGAL REQUIREMENT, to withhold this car. As its under warranty they will of course be providing a loan vehicle.

A car IS NOT perfectly driveable with a defective brake servo.
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Sat 1 Nov 2003 08:43
Renault Scenic Hissing from under Brake - DL
The garage are 100% correct in their action - they are doing you and other road users a favour.

--
groups.msn.com/honestjohn - Pictures say a thousand words.....
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Sun 17 Aug 2014 00:31
Renault Scenic Hissing from under Brake - gddy1

Blast from the past I know, but I have just encountered this "hissing" problem, and was advised by a local mechanic that it was the servo that was at fault. He said to get a replacement but there was no hurry as it is not a major worry.and sorry Altea Ego, I agree with David, I have driven 346 miles so far with no loss of brake function so to say "a car IS NOT perfectly drivable with a defective brake servo" is, in my opinion, twaddle also.

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Sun 17 Aug 2014 00:53
Renault Scenic Hissing from under Brake - Bolt

Blast from the past I know, but I have just encountered this "hissing" problem, and was advised by a local mechanic that it was the servo that was at fault. He said to get a replacement but there was no hurry as it is not a major worry.and sorry Altea Ego, I agree with David, I have driven 346 miles so far with no loss of brake function so to say "a car IS NOT perfectly drivable with a defective brake servo" is, in my opinion, twaddle also.

You may think its twaddle but you are wrong,the above posts are correct,what you may have missed is if the servo stops working it will be a lot harder to press the pedal and operate the brakes, you cant put enough pressure on the pedal to give the braking the servo can, thats what its there for

Rather dangerous in my opinion

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Sun 17 Aug 2014 11:12
Renault Scenic Hissing from under Brake - Andrew-T

<< You may think its twaddle but you are wrong,the above posts are correct,what you may have missed is if the servo stops working it will be a lot harder to press the pedal and operate the brakes, you cant put enough pressure on the pedal to give the braking the servo can, thats what its there for

Rather dangerous in my opinion >>

I'm not sure about this. The garage is clearly correct in strongly advising a customer not to risk driving, but I would say that is as far as they should go. On the other hand, a car's assisted brake (or steering) system is designed to remain operative if the assistance fails, on the assumption that the driver becomes aware of a sudden failure and increases the effort. I would not expect a hissing 'servo' to be a warning of sudden failure? Does one of our experts know differently?

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Sun 17 Aug 2014 12:24
Renault Scenic Hissing from under Brake - Bolt

I see your point, but if assuming the assistance stops and you are traveling at speed it takes a lot of foot pressure to make the brakes work, harder still to do emergency stop

whether you would not expect a sudden failure or not its possible

I think steering assistance is different in that its speed/load related ie parking assistance

Just my opinion right or wrong

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Sun 17 Aug 2014 15:55
Renault Scenic Hissing from under Brake - galileo

I suggest you find a quiet bit of road with a gradient, turn off the engine, press the brake several times till the pedal goes really hard, then let it roll and try to stop it from 10 mph.

Then you'll know what effort you need to stop if the servo does fail.

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