Hello,

I have a Superb 2, 2.0 CR 170 Diesel with the DSG gearbox.

If I leave the car for more than a day or two then return to it the brake pedal goes hard. I have to press it to start the vehicle anyway and when the servo is working it returns to normal.

Does anyone have an idea why this happens? I am guessing it is NOT normal.

Thanks in advance.

SJ

Perfectly normal, don't worry about it.

Ray

I'm not a mechanic.

Perfectly normal, don't worry about it.

Are you sure? I'd be suspecting a broken one way valve (most likely) or maybe a punctured vacuum line to the servo or even a faulty servo.

Don't like the sound of this issue -- its the kind of thing you can imagine a crash because: "the brakes were fine all journey, then i pressed them just before i crashed and there was very little braking effort".

Are you sure? I'd be suspecting a broken one way valve (most likely) or maybe a punctured vacuum line to the servo or even a faulty servo.

Anything that relies on maintaining a vacuum whilst the pump is operating clearly only needs to be made to tolerances that support that operation. After the vacuum pump is off, maintaining that vacuum relies on everything related to it being perfectly airtight. If that's what you expect in modern car production, I'd lower your sights considerably.

I said that it was perfectly normal behaviour because it is. I have the identical car to the OP and - if I leave mine for the period specified - that's what happens, as it does with the majority of other vacuum-assisted braking systems, whatever the make.

Either that, or I'm deliberately giving out dangerous advice - you choose.

Ray

Anything that relies on maintaining a vacuum whilst the pump is operating clearly only needs to be made to tolerances that support that operation. After the vacuum pump is off, maintaining that vacuum relies on everything related to it being perfectly airtight. If that's what you expect in modern car production, I'd lower your sights considerably.

I said that it was perfectly normal behaviour because it is. I have the identical car to the OP and - if I leave mine for the period specified - that's what happens, as it does with the majority of other vacuum-assisted braking systems, whatever the make.

Either that, or I'm deliberately giving out dangerous advice - you choose.

Ray

Fairy 'nuff

It's probably nothing to worry about, but when it comes to brakes I always go with the if in doubt have a good garage give it a once over.

As above, nothing worse than no brakes, so the garage route gives you piece of mind.

It sounds normal to me. Does the same thing happen if you pump the brake pedal whilst the car is running?

It sounds normal to me. Does the same thing happen if you pump the brake pedal whilst the car is running?

When the car is running the brake pedal goes down around an inch or so and I have full braking. The reason for the post was that the pedal goes stiff / hard when left for more than a day or two as if I had been pumping the brake with the engine off. It's stiff / hard to press, taking considerable effort to push it down from the top of the pedal travel.

Does your car have hill hold? Do you park on a slope?

The reason for the post was that the pedal goes stiff / hard when left for more than a day or two as if I had been pumping the brake with the engine off. It's stiff / hard to press, taking considerable effort to push it down from the top of the pedal travel.

What you feel is the brakes as they would be without servo assistance. You seem to have missed the point entirely that it's the "day or two" that is responsible, as most cars can maintain some sort of vacuum pressure for up to that time, but not afterwards. Balloons leak air, servos let air in - that's how it is. Immediately you fire up, you get full braking - so do I - it's NOT a fault, EOS.

Ray

What you feel is the brakes as they would be without servo assistance. You seem to have missed the point entirely that it's the "day or two" that is responsible, as most cars can maintain some sort of vacuum pressure for up to that time, but not afterwards. Balloons leak air, servos let air in - that's how it is. Immediately you fire up, you get full braking - so do I - it's NOT a fault, EOS.

Ray

As Ray says, this is quite normal, very few vehicles will hold their vacuum for several days. Retired motor vehicle technician with over 46 years experience. When an after market brake servo was fitted this was the most frequent questioned asked within a few days, is there something wrong with my brakes the pedal travels further, it was ok before you fitted the servo?. An information leaflet was always supplied by the maker covering this detail.

As in all suspected cases of a braking problem it is best to err on the side of caution, if in doubt have it checked out.

I am sure you will obtain the same answer from your dealer, that your vehicle is ok.

I've never noticed it happening that fast (2 days), but I'd agree that it's entirely normal for vacumn servo assisted brakes to "go hard" if the vehicle is unused for several days.

I dont need to press the brake pedal to start my DSG PD140, as long as the car is in P then I just turn the key and go without pressing the brake pedal at all.