I am about to install my Alcon front brakes. When I change the fluid (for high performance stuff) should I completely drain out the old fluid from the system or not? I am a little wary of letting the master cylinder run dry. Getting all the air out of the system after this can be a PITA.

Any tips would be welcome.

Thanks

Paul

 

Never completely drain. Keep bleeding until new stuff (adding a bit more at a time) starts coming out of the brake bleed nipple. Helps when the new stuff is a radically different color. Bleed usual order, farthest from master to nearest (RR, LR RF LF). Getting air in there is bad mojo according to my shop manuals and the install instructions that came with my brakes.

Tribal stuff:

Read lots of posts on how pumping with the pedal to do this (two people obviously) is bad and you need to use a pressure bleeder or some-such. I just never pump the pedal all the way to the floor to pump the stuff out, just a bunch of little pushes. Never had a problem, but I don't know.

Those more in the know seem to argue that the whole "boiling fluid" thing is pretty bull**** and what most people are feeling is pad heating and glazing of the pad material. You can read posts with people saying things like "boiled fluid today, things mushy for the next day, even after bleeding." Which makes no sense. I've never had a pedal-to-the-floor oh-**** boiling the fluid experience. Hence I tend to use Valvoline stuff you can get at Kragen and not worry over-much about bleeding all the old stuff out.

One thing I never see people discuss, although you can read about it on the Stoptech web site, is that the ABS system has some fluid trapped in it all the time in various curcuits that only open when the ABS is pulsing. So I suppose if you are a real nut about fluid, you can debate how to invoke things with the VAG to release this into the main circuit for bleeding...

Me. Slightly above average grade fluid, let no air in, pedal never to the floor, usual bleeding order. Never had a problem.

-Zain

PES G2 A4
Stoptech brakes

 

Power bleeders can be bought from German Auto parts (Adirondak Auto) for 50 bucks shipped, an awesome tool!!! If you have a 5Spd, its a good idea to bleed the cluth area, its on the top side, cant miss it if you are a lookin' for the nipple. It can be seen from the top if you look below and to the left of the coolant reservoir, its down there. I bled it just before drivers front....some say this is BS, but tell me what color comes out!!...mine was ugly brown for several ounces until it became pee yellow again. (do this with a power bleeder only??)
As for fluid, I have used Motul 5.1 and its got a better brake feel to it then a dot 3 or 4, but the Dot4 is fine, I have switched to Ford brand brake fluid, ask for fluid at the counter, look on the back, make sure the boil point is 450F and that its synthetic and you are good!! I sorta disagree with Zain on the fluid, I have seen mine get hot enough to seep through the caliper pots and really grease up the rotors....but I have Wilwood calipers and they certainly aint stop techs!!.
As for the ABS, I go out after the brake change and beat on the brakes in order to bed them in, also whale on the ABS (with Alcons, it can be done at 100+ mph!!) a few times, this will push any of that trapped air that MAY be in the ABS pump. Then I re-bleed the next day and re-top off the master cyl. Good luck with the Alcons, if they are B types, you better have a set of harnesses!!

 

I bought a power bleeder especially for the job. The brakes I have are "World Challenge" six pot with 14" disks. I should have little chance of fade with these! Definately doing to be wearing harnesses at the track from now on!