DarrenW
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| posted on 30/3/13 at 02:04 PM |
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Audi A3 Brake challenge
Ive got a 1999 Audi A3 1.8T Sport. Been off the road for a year so getting it ready for MOT.
It pumped its brake fluid out when i first got it moving. This turned out to be the washers failed on one of the rear calipers (where the flexi
connects to the calliper). Ive cleaned all of the brakes up and obviously had to bleed the system following the seal failure. Im having a nightmare
getting a good pedal feel. Reading the forums suggests it is common to have issues trying to bleed the system. Anybody on here that can help?
Pedal is quite firm when engine off. However soft when engine is running. i dont have tax or test yet so cant really go for a road test yet. I do
recall before taking it off the road that the pedal feel wasnt that great. i dont think it is the Master Cylinder and dont want to replace it just yet
as im told its even harder to bleed them after that job.
Has anyone had similar issues and found a good fix?
Ive read that some Audis need the clutch slave cylinder bleeding as well - not sure if this is only on the TDi's though. Does the MC need to be
bled?
Cheers,
Darren.
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bashracing
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| posted on 30/3/13 at 03:44 PM |
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there's a bleed nipple on the master cylinder, if you dont bleed that first you wont ever get a good pedal
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Slimy38
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| posted on 30/3/13 at 04:39 PM |
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The VAG braking systems respond well to pressure bleeding rather than the more traditional two man method. Something like an eezibleed will make it
easier.
If the whole system bled itself dry then the ABS unit will need special attention, they can be an absolute nightmare to get working. I've not
seen a definitive method of getting rid of all the air in the ABS unit, it seems different options work for different people. At the very least
you'll need access to VAGCOM in order to cycle the unit.
When I did my brakes, I was conscious that the clutch also uses the same fluid, however I didn't bleed the clutch as I couldn't crack the
screw. It doesn't appear to have affected the braking efficiency though.
If the car has been stood for a year, are the brake flexi pipes still ok?
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rusty nuts
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| posted on 30/3/13 at 05:52 PM |
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It's sometimes better to bleed ABS brakes with the engine running or the ignition switched on, a pressure bleeder tends to make the job easier
Check your workshop manual if you have one for the correct procedure for your car. Can check for you if you let me have the car details or reg but
won't be able to do so until Tuesday
Had problems once bleeding an Audi clutch after replacement, couldn't get any fluid through the system even when using a pressure bleeder, a
vacuum bleeder and someone pressing the clutch , replaced master cylinder, still the same . It turned out that the spigot for the clutch master
cylinder feed off of the brake fluid reservoir was stilled capped off, possibly like it from new
[Edited on 30/3/13 by rusty nuts]
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DarrenW
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| posted on 30/3/13 at 06:06 PM |
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Thanks for fast replies.
I carefully inspected all 4 corners for pipe corrosion and rotten flexi's. All look good. Only sight issue might be drivers side rear calliper.
It seemed a bit tight to wind back compared to the passenger side. Might need a new one at some point. I worked it back and forward a few times and it
got a bit looser. Hand brake linkages are all good.
I dont think the system has bled totally dry, but air could have easily got to the ABS unit. Master cylinder has 2 bleed nipples. I bled it as best as
i could (not very accessible). Rear nipple first.
To be honest i had to use one of those auto bleed pipe jobs - clear flexy blocked off at end end with the split in it. Had to do to mostly on my own.
My 8yr old daughter was a great help when she was there. At the rear i took the calipers off, raised them and bled (with wind back tool in place).
This was to make sure there was no air in the flexy's. Second time i bled the system i had the engine running.
Road test was ok ish, pedal feel not great but it did stop. Should get better when the last of the corrosion wears off the discs. Defo need better
pedal though. MOT might be iffy.
Re VagCom - can you cycle the ABS just using one of those £30 ebay code readers or do you need the full blown pro kit?
Is there anybody near Bishop Auckland with a VagCom and easibleed i could borrow please? Or anyone with the kit can give me a hand for appropriate
number of beer tokens?
I had all of the wheels off when i was working on it and bleeding the system - would that make a difference?
[Edited on 30/3/13 by DarrenW]
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ian locostzx9rc2
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| posted on 30/3/13 at 07:11 PM |
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Not sure if you have been bleeding the brakes with the engine running as you need too...
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owelly
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| posted on 30/3/13 at 11:13 PM |
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Pop out, start the engine, pump the pedal and then wedge the pedal down (trolley jack handle against the front of the seat then slide seat forwards or
similar!). Switch off car and go to bed. In the morning, start engine, remove wedge and inspect for leaks. See if the pedal feels any better. Worth a
try?!
http://www.ppcmag.co.uk
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Slimy38
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| posted on 31/3/13 at 07:59 AM |
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quote:
Originally posted by owelly
Pop out, start the engine, pump the pedal and then wedge the pedal down (trolley jack handle against the front of the seat then slide seat forwards or
similar!). Switch off car and go to bed. In the morning, start engine, remove wedge and inspect for leaks. See if the pedal feels any better. Worth a
try?!
Aha, I remember that technique from my bike brake bleeding, we used to call it the voodoo method. We called it that because it shouldn't make
any difference but for some reason it does! 
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DarrenW
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| posted on 8/4/13 at 08:37 AM |
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UPDATE -
Despite bleeding the brakes twice, engine running, 2 man method, over 1 litre pumped through etc etc - i bought a Sealey pressure bleeder off ebay and
did them again. I got my daughter to also pump the brake pedal at same time - managed to get loads of air out of all 4 calipers. Brakes now far far
better. Pedal not quite normal modern car like feel, but way better than before and brakes definitely stop the car. Of course my 8yr old got the
praise and recognition for fixing the brakes!
I need a cheap laptop now so i can install the vagcom software and get the ABS unit activated for next bleed - ive heard there can be old fluid and
trapped air in these which reduce their effectiveness.
Thanks all for your help and U2U's. This led to purchase of pressure bleeder and improved pedal.
Darren.
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