I don't know if there is a way to manualy bleed the abs control box or not but they are picky. Maby search about it. I the abs unit is the same used in many German cars like audi and vw.

Did you try crimping lines individually to check for major pressure difference?

Good luck, wish I could help in person

 

You could check the voltage of the abs unit to see if its functioning properly?

 

I would think the problem would be similar to this. If the fluid emptied to a point where air gets in the abs dump valves you can bleed the brakes for a month and it wont get better. There has to be a way to bleed the unit but I'm afraid it would have to be done with the consolt2 or some bs like that.

As for voltage, unlikely. You can unplug the abs unit pull the bulb and drive the car with no abs if you wanted

 

Thanks. Ill look into the ABS unit. I just wondering why it works good sometimes and other times it doesnt.

 

Do a good couple abs stops at 100mph+ and see if it works itself out. JK!

 

Backfromthedead. What ended up happening with this whole situation. Im going to be changing rotors, pads, lines and fluid soon and want to know what im in for.

 

if your master cylinder went dry then you need to remove it and "bench bleed" it

 

I just let my master cylinder run dry during a normal bleed on a 2000, and I was able to rectify the situation (poor stopping even after a normal bleed with no bubbles) by just doing an on-the car bleed of the master cylinder, per the factory service manual.

Basically, I used a ziplock bag to catch the fluid, and quite a few bubbles came out the first few pumps. Did two trips around the pattern normally bleeding the calipers after that and she's as good as new.

Details of my process:
http://forums.maxima.org/showpost.ph...03&postcount=8

Good luck!

 

I was going to suggest the same thing...If air got into the MC caused by low fluid, it's not as simple to bleed as the 4 corners when clearing out a line or wheel cylinder.

The symptom you're describing, soft pedal, sometimes harder then other times, going to the floor a lot, all classic symptoms of a air in the hydraulics.

The guy above suggested a MC bleed while it's on the car, could be your option to save some time, but it's going to be messy. Take the whole thing out and bench bleed it may take 30 more minutes, but will be a bit more effective, and easier to clean up afterwards.

 

Sh!+, just realize this is a 2+ YO thread...I'm sure the problem's been corrected by now!?!

 

sorry for re-resurrecting an old topic but im in the same boat now. i did the 6th gen brake swap on my 5th gen and i cannot get my pedal to get firm. me and my friend bled all the 4 wheels about 3 or 4 times, no more air bubbles, all new clear fluid is coming out and the pedal still falls to the floor and is very spongy, the classic air in system symptoms. i have checked EVERYTHING, no leaks anywhere, new pads/rotors etc... i read about air getting into the abs system/actuator or the master cylinder because my genius a$$ let the brake lines empty do i have to go to the dealer to get this problem fixed? or is there a way to bleed the abs system or master cyliner without paying the dealer a ton of cash? if so, where and how do i bleed it? and is this the problem or is something else wrong? i know the master cylinder can go bad but everything was working perfectly before i did the caliper swap so i doubt its bad (im at 90K miles) unless it just has air in it, any and all help is appreciated, thanks!

 

here you go, hope this helps http://www.mediafire.com/?hoz3ubeta351suu

 

ok thanks for the info... what im getting from all this is this... disconnect the two brake lines from the master cylinder, fill the master cylinder with new fluid, then have a partner press the brake pedal with the holes open and let the air/fluid come out, then put my fingers over the holes as my partner releases the brake pedal as to not let air back in, do this several times so no more air comes out and reconnect the brake lines... did i miss anything??? hopefully this will cure my softy pedal
thanks again everyone

 

when i bled my brakes I let the master cylinder empty......

Re-bled the whole thing completely, works fine.

How do you bleed the brakes? Are you sure there is no air getting back in? WHat I did, is connect a piece of tubing to the nipple. Then place tube in a bottle of coke with some fluid at the bottom. Have person press pedal, open bleeder, close, tell person to release, repeat.

That way, if the line wants to "suck" anything back in, it will suck back brake fluid, not air. Do it until no bubbles come out. Took a while for me after letting the master empty.. I think it took a whole large bottle of brake fluid.

You can even do it alone that way BTW. Did that the 2nd time. When you release pedal, nothing really happens (it doesnt really "suck back"). So open bleeder, press 5-6 times, close quick) then refill master. check your tubing, you will see if there are still bubbles in there or not... if still bubbles, do again. if not, done.

oh and make sure you got no leak anywhere. of course if you got a small leak on the new line at the fitting, wont work...