BRAKE PROBS ON S6!!!!!
Discussion
Im wondering if anyone has had this problem before with their s6? My 2000 s6 started labouring tonight as if brakes were locked then esp and airbag light came on dash. I pumped the footbrake for a while and the brakes seemed to release but now you really have to push the pedal in a lot further to stop. once id turned the ignition off and on the dash warning lights have since went out but the pedal is nowhere near as sensitive as it should be. I got new brakes put on about 6 weeks ago. Any ideas welcome chaps
thanks
thanks
If it is the servo, it will need replacing, have had them fail in this manner on A4's a few times, never seen it on A6 but is essencially the same so quite likely.
What I have seen before...
Something internal goes wrong with the servo (no idea what, but can be caused by water ingress, check the plenum area the drains can get blocked) As the engine generate vacuum instead of assisting your foot effort when pedal pressed, the vacuum actually pulls the brakes on slightly, giving you the impression of a seized caliper, but when you check on the ramp you find all 4 wheels are on, pump the brakes a few times, or pull the vacuum line out of the servo and the brakes unseize.
With yours sounds like it did that for a bit and when you pumped the brakes it stoped doing it, now either the servo isnt working, no vacuum assistance at all, hence the need for more brake pedal effort, or in the process of having the failier where the brakes were on, you glazed you pads.
But this is a mechanical fault, wouldn't really explain your warning lights, particularly the airbag one, unrelated system. Did the lights come on when the fault occurred or when you were starting the engine????
What I have seen before...
Something internal goes wrong with the servo (no idea what, but can be caused by water ingress, check the plenum area the drains can get blocked) As the engine generate vacuum instead of assisting your foot effort when pedal pressed, the vacuum actually pulls the brakes on slightly, giving you the impression of a seized caliper, but when you check on the ramp you find all 4 wheels are on, pump the brakes a few times, or pull the vacuum line out of the servo and the brakes unseize.
With yours sounds like it did that for a bit and when you pumped the brakes it stoped doing it, now either the servo isnt working, no vacuum assistance at all, hence the need for more brake pedal effort, or in the process of having the failier where the brakes were on, you glazed you pads.
But this is a mechanical fault, wouldn't really explain your warning lights, particularly the airbag one, unrelated system. Did the lights come on when the fault occurred or when you were starting the engine????
sorry airbag light didnt come on - i meant abs!! the lights came on as i was driving and at the time the brakes seized up -so fairly accurate system. I was told today if its a servo problem the brake pedal goes rock solid instead of limp! (which is what happened at the start of this fiasco). At the minute there are no warning lights on , the brakes work but have to push almost right to the floor. Are u saying there are pipes i could clean to maybe solve this TTech?? where is the plenum?? sorry for my ignorance and thanks for ur help so far BTW
cheers ryan
cheers ryan
Edited by daphantom on Monday 10th December 21:10
If its an S6 it wont have a vacuum servo, as the engine has a turbo, it has the pressure sphere for the braking system. Tame Technician are you an Audi mechanic by any chance?, if so maybe you can push him in the right direction.
Check Sphere Pressure
Check Pressure sensor
Check Brake Master cylinder
Check Sphere Pressure
Check Pressure sensor
Check Brake Master cylinder
Forget everything i said.The plenum is the area under the bonnet, right at the back,er sort of the bottom of screen. The wiper motor is there and the battery on some models, this often fills with water cos the drain holes get blocked with leaves and sh*t. If you find water in there and push out one of the grommets to drain it, you will still have the brake fault cos the damage is done. So you cant fix it by cleaning out, sorry.
The servo can fail in a number of ways, Usual failier (any make or model, ford common) pedal does go hard, I wouldn't say solid but lots of effort required for little braking power.
The odd thing the Audi's do, when the servo is effectively acting like you have your foot rested on the pedal, will give the limp/long pedal you had, because the brakes are already on. But you will only have this pedal feel while the brakes are on/seized, if by pumping the pedal or what ever, it goes back to normal, you wont have the long/soft pedal anymore.
Hope this is making scenes.
You need to get a bit more info on what is happening to the car, cos I'm purly making a n educated guess based on your description and what other audi have done, could be somthing completely different.
So are all the wheels turning freely now, do you have one or a number of seized calipers etc. If its one or two, it wont be the servo. The fact that you now have a long pedal and they no longer apear to be seized is making me think caliper but checking the wheels turn round freely is the only way, but to do after a drive so things are warm.
Basic servo test, engine off, pump brake pedal lots 10 times, should be dead hard, then start engine with foot on brake quite hard, does it go down a bit. Servo is working if it goes down. Then recheck for seized brakes with engine still running. If they all on, servo is Fu*ked.
As you had the ABS light, you should have a fault code logged, could get the memory read at a local dealer, VW or Audi. 0.3hrs labour. £88(ish) x 0.3 + VAT.
The servo can fail in a number of ways, Usual failier (any make or model, ford common) pedal does go hard, I wouldn't say solid but lots of effort required for little braking power.
The odd thing the Audi's do, when the servo is effectively acting like you have your foot rested on the pedal, will give the limp/long pedal you had, because the brakes are already on. But you will only have this pedal feel while the brakes are on/seized, if by pumping the pedal or what ever, it goes back to normal, you wont have the long/soft pedal anymore.
Hope this is making scenes.
You need to get a bit more info on what is happening to the car, cos I'm purly making a n educated guess based on your description and what other audi have done, could be somthing completely different.
So are all the wheels turning freely now, do you have one or a number of seized calipers etc. If its one or two, it wont be the servo. The fact that you now have a long pedal and they no longer apear to be seized is making me think caliper but checking the wheels turn round freely is the only way, but to do after a drive so things are warm.
Basic servo test, engine off, pump brake pedal lots 10 times, should be dead hard, then start engine with foot on brake quite hard, does it go down a bit. Servo is working if it goes down. Then recheck for seized brakes with engine still running. If they all on, servo is Fu*ked.
As you had the ABS light, you should have a fault code logged, could get the memory read at a local dealer, VW or Audi. 0.3hrs labour. £88(ish) x 0.3 + VAT.
cheers tame tech -everything u said there made perfect sense! my car always get covered in leaves because of where my house is ,so thats prob the reason for plenum getting blocked up. situation at the minute is - no warning lights at all on , all wheels moving freely , only prob is - brake pedal very limp but brakes do work. I'll take it to my local indy and get a new servo.
thanks again much appreciated
thanks again much appreciated
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