A4 Tdi Brake Servo
Discussion
Twice yesterday as I approached junctions I put my foot on the brake pedal only to find it pretty solid with no servo assistance - for a moment I thought I wasn't going to stop at all.
By coincidence the car was due in today to an independent garage for a 60k service, brake fluid change, and cam belt change. I asked them to investigate and they reported that it is likely the brake servo diaphragm is damaged.
Apparently this can happen on some VAG cars if the bulkhead drain vents get blocked allowing water to build up in the bulkhead and be sucked in to the servo, and in turn that can allow water to be sucked in to the diesel/vacuum pump.
The car is over four years old and out of warranty, but is this kind of failure expected at under 60k miles or might I have a case for asking Audi to investigate and contribute to the cost of parts and/or labour? I understand that the servo and vacuum/diesel pump may cost £250 each.
Has anyone else experienced a problem like this?
By coincidence the car was due in today to an independent garage for a 60k service, brake fluid change, and cam belt change. I asked them to investigate and they reported that it is likely the brake servo diaphragm is damaged.
Apparently this can happen on some VAG cars if the bulkhead drain vents get blocked allowing water to build up in the bulkhead and be sucked in to the servo, and in turn that can allow water to be sucked in to the diesel/vacuum pump.
The car is over four years old and out of warranty, but is this kind of failure expected at under 60k miles or might I have a case for asking Audi to investigate and contribute to the cost of parts and/or labour? I understand that the servo and vacuum/diesel pump may cost £250 each.
Has anyone else experienced a problem like this?
I had a 2001 (Y-reg) A4, 1.9 TDI 130bhp. Had this problem occur after coming back up the motorway, suddenly all braking assistance disappeared and I practically had to stand on the brake pedal for it to stop.
Car was under warranty (I bought it in October 2004 on the Audi Approved programme), I got it recovered, they replaced the vacuum pump. Got the car back, within 24 hours the fault had recurred. Went back in, replaced the brake servo. Got it back, went again within 24 hours. Discovered that first replacement servo was faulty, replaced again.
This time things started getting more unpleasant - after 2 hours or so on the motorway the hydraulics would start playing up. This culminated in me pressing the pedal all the way to the floor and bugger all happening...
Got the car recovered all the way back from Watford (I live near Bristol), by the time Audi Roadside came out to have a look at it the following morning all was fine.
In the end I changed the car, got a 2003 52-plate 1.9 TDI Quattro. Had no problems with the brakes on this!
What was particularly worrying though - one of the courtesy cars I had while mine was being repaired (an A3 2.0 TDI Sportback) also had the same fault occur with the servo... although according to the technician at my local Audi centre the servo in this car was from the same batch as the first replacement they'd put in my A4.
Car was under warranty (I bought it in October 2004 on the Audi Approved programme), I got it recovered, they replaced the vacuum pump. Got the car back, within 24 hours the fault had recurred. Went back in, replaced the brake servo. Got it back, went again within 24 hours. Discovered that first replacement servo was faulty, replaced again.
This time things started getting more unpleasant - after 2 hours or so on the motorway the hydraulics would start playing up. This culminated in me pressing the pedal all the way to the floor and bugger all happening...
Got the car recovered all the way back from Watford (I live near Bristol), by the time Audi Roadside came out to have a look at it the following morning all was fine.
In the end I changed the car, got a 2003 52-plate 1.9 TDI Quattro. Had no problems with the brakes on this!
What was particularly worrying though - one of the courtesy cars I had while mine was being repaired (an A3 2.0 TDI Sportback) also had the same fault occur with the servo... although according to the technician at my local Audi centre the servo in this car was from the same batch as the first replacement they'd put in my A4.
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