Im looking for a little help with my brakes. Ive gone as far as I can on my own. I have a 1997 A4 1.8TQ. Here's the deal:

My ABS controller spazzed and would slowly lock down my passenger front wheel. I purchased an ABS unit with exact mathing audi and bosch part numbers. I installed that whole unit (controller and pump) yesterday and the ABS and Brake CELs turned off. At this I got excited and proceeded to attempt bleeding the brakes, beginning in the rear. After trying for several hours and pumping for 5 mins sometimes I still get no fluid from the rear calipers. Now for some questions.

1. I have VAG-COM and it will connect to other modules (ie: 01-Engine,.,,) but when I try to connect to the ABS controller (Address 03) to cycle the ABS ( i heard this was needed for when the ABS unit is dry), I get a "Cannot synch Baud rate" error. Is it possible the ABS unit needs to be recoded?

2. Should I be able bleed the brakes withou using VAG-COM at all?

3. Is there anything not obvious that I need to know to bleed brakes on this car?

I am supremely grateful for any responses you guys can give me.

 

you shouldnt need vag com to bleed brakes. what version of vag com do you have?

do you know how to bleed brakes? theres a certain procedure that you have to get correct, but they are the same as for any other car. i would suggest getting a power bleeder- either vacuum or pressure, it makes it much easier to do especialy by yourself.

make sure you have a 2x4 or a brick under the brake pedal so you dont push it down too far and damage the seals in your master cylinder.

is the fluid going in at all? if the fluid in the resevoir is going down, it has to be going somewhere. if its not then you need to figure out why. this is why a power bleeder is nice, you just open the bleeder and it forces the fluid thru, no need to pump.

 

If the abs module is dry then you need a VAG. If you just replaced the computer half of the unit you wouldnt have needed to bleed anything.
http://www.ross-tech.com/vag-com/cars/absbleeding.html

Try and set the baud rate manually... If it is too fast (or too slow) it wont be able to connect. I dont know where the option is for that if you have VAGCOM on a laptop (i have it on palm). Codeing doesnt really have anything to do with that, it just cant connect because the connection is trying to run too fast or too slow.

 

The fluid in the resevoir is not going down, I have the cap off while bleeding as well. Ive bled brakes before, just not on an Audi. I was going to replace just the electronic part but the valves were connected to it with thin ribbon circuitry that I did not want to break.

Im currently using VAG 409.1 registered with an ebay cable, it has worked before on windows xp, but the laptop I have is on Windows 2000 :/ . I guess my first step would have to be getting vag to connect to the ABS unit. Ive tried setting the "Start Baud" setting to 9600, since that is the rate that my USB port for the cable is set to, no luck with that. Should i set them both slower?

Once I get the ABS controller bled I will be happy to buy a power bleeder since it will be a lot cheaper than the $2100 Audi quoted me to fix this.

 

Yeah try them slower, and faster too. Each module varies for my car, some are as slow as 4800 i believe and some are as fast as 1100.

 

ok I got the baud rate figured out. Set it to 115200 and it connect. Now qhen I go under ABS controller-03 > Basic Settings-04 all of the addresses say ERROR not avaiable

 

Do you guys think I need to put the stock radio back in? Could that be keeping the VAGCOM from communicating?

 

I think some modules used bleeder screws (not for sure though), mine is a 99 and it will allow me to go to basic settings, but the block wont work, so it wont turn the pump on..

 

I go everything straightened out. Thank you all for your inputs.