Brake pedal goes down all the way

[kamranali44]

Hi Guys,

I have an issue with my Passat where the brake pedal goes to the floor. The brake pads seemed to be fine (Checked by the mechanic). I had this issue about two weeks before and when mechanic bled the brakes out, it did go away however it has decided to come back and bleeding the brakes did the trick again but I need to figure out where the problem is.

The car is not losing any brake fluid. Could it be the master cylinder?

My car is VW Passat 2.0 Diesel TDO 140BHP 2006 (56 Plate - UK number plate). Do let me know if I have missed out any information or details.

Thank you for reading and I could not find similar thread so this can help someone in the future as well.

[RichardSEL]

I assume you're not now driving it?

This is something that a qualified VAG indie or dealership should investigate -- not something for the backstreet mechanic, no matter how experienced. Someone who's actaully at the car should tell, not by a forum best guesstimate.

But at least you can get a VCDS Autoscan to see whether any of the brake modules are reporting a fault?

BTW, if it were the master cylinder it would always be pedal going to the floor irrespective of if the system's bled off

[kamranali44]

I assume you're not now driving it?

This is something that a qualified VAG indie or dealership should investigate -- not something for the backstreet mechanic, no matter how experienced. Someone who's actaully at the car should tell, not by a forum best guesstimate.

But at least you can get a VCDS Autoscan to see whether any of the brake modules are reporting a fault?

BTW, if it were the master cylinder it would always be pedal going to the floor irrespective of if the system's bled off

I had the car scanned and no error codes show up when it is scanned by VCDS.

The car is parked. I wish I could drive it but no that crazy yet

I will leave it with another mechanic tomorrow to see if he can find any issues with it (luckily, I have AA cover up to 10 miles). I just don't want to trust the mechanic and then the same issue comes back in two weeks.

VW Passat 2006 2.0 TDI Diesel 140 BHP

[grant19841]

must be air entering the system somehow.



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[Rob69]

Good points raised by Richard! My only other thought is if it's not air in the system or master cyl, then a damaged flexi hose to a caliper, which is ballooning up when the pedal is pressed. Maybe at some point in the past someone clamped a hose, which can damage the internal lining. These are much harder hoses (presumably to allow ABS to function properly) and shouldn't be clamped like in the old days.

[kamranali44]

Hi

Grant,

The air is my guess as well and mechanic has told me that he would look out for it.

Rob,

I will keep an eye out for it hopefully it's not a big job. The rear left caliper has been changed nearly a month ago so it seems fine. Let's see the result from today and then go from there.

Thanks guys.

VW Passat 2006 2.0 TDI Diesel 140 BHP

[Rob69]

Those calipers can be tricky to bleed fully for the first time.

[zollaf]

don't know if yours has a load sensing valve on the back but they can leak and allow air to suck in and cause this fault. you can hear the air in them when you brake and if you go forwards and brake and the pedal goes down, then reverse and brake and get a good pedal then this points to it as faulty.

[kamranali44]

Hi Guys, I have been on holiday and have not kept up with the thread. The problem was with the Servo and when the servo was replaced, the car is driving brilliantly. Thanks for your help everyone. :-)

VW Passat 2006 2.0 TDI Diesel 140 BHP