# Very weird brake bleeding issue



## slavrenz (Apr 16, 2010)

On Saturday, I spent most of the day changing pads and rotors on all four corners. Everything went fine, until I decided to bleed the brakes at the end (the old fluid was looking pretty funky). The car is a 2000 Maxima SE with anti-lock brakes, so before I began the bleeding process, I disconnected the negative battery cable per repair manual instructions to disable the ABS.

I have bled brakes dozens of times, never with any problems. But this time, I went around the car to all four corners, in the specified order, and bled until the fluid came out crystal clear. I ended up bleeding each corner 7 times, and all air bubbles were gone by the end of the 3rd round. The reason I kept going is because every time I would finish and start the car up to test the pedal, it felt really mushy.

Now I'm no idiot, and I made sure to press the pedal a few times to build up resistance. I also kept the master cylinder full of fluid, and there are no leaks or visible issues with the brake system. The car stops well enough, but does anyone know why I still might have a mushy pedal?


----------



## rogoman (Dec 16, 2004)

Did you do this by yourself? The proper procedure is to have another person pump the brake pedal several times and then hold it down while you bleed the cylinder.


----------



## pulsar86 (Aug 13, 2009)

Just an idea, but check the condition of all rubber brake hoses in the system , you could have a hose that is failing and ballooning out when pressure is applied to the line.


----------



## slavrenz (Apr 16, 2010)

Thanks for the replies so far. As I mentioned in my first statement, I have bled brakes tons of times, so this is more than just a case of me not knowing how to do it correctly. I also closely inspected all of the brake lines as I was bleeding them, and could find no abnormalities.

I'm beginning to think that this had something to do with the ABS module, but since I disconnected the negative battery cable before bleeding (effectively disabling the module), I don't see how that's possible.


----------



## ntech (Apr 13, 2010)

highly doubt the ABS module had anything to do with it. Some how you introduced air into the system. How did you bleed them? vacuum or manual? Buy more brake fluid and do it again. Check to make sure you got no leaks first! Bled a million nissan brakes with no issues. just try it again


----------



## chimmike (Oct 17, 2002)

it's going to feel mushy for a little while and firm up over time. if you have no bubbles you did it right.


----------



## Faja (Aug 31, 2009)

chimmike said:


> it's going to feel mushy for a little while and firm up over time. if you have no bubbles you did it right.


If brakes are still mushy you might have a problem with the master cylinder - try bench bleeding that also.


----------



## ntech (Apr 13, 2010)

Faja said:


> If brakes are still mushy you might have a problem with the master cylinder - try bench bleeding that also.


Forget bench bleeding! bleed the master cylinder like you would any other wheel. Have someone hold the pedal down, then crack one of the lines on the master cylinder. Then tighten before they come back up with the pedal. repeat for both lines a few times.


----------



## slavrenz (Apr 16, 2010)

ntech said:


> Forget bench bleeding! bleed the master cylinder like you would any other wheel. Have someone hold the pedal down, then crack one of the lines on the master cylinder. Then tighten before they come back up with the pedal. repeat for both lines a few times.


There's no way the master cylinder needs to be bled - I only replaced one caliper.

Anyways, the car was my father-in-law's, and he said the brakes have firmed up somewhat, so I'm not too worried about it any more.

Thanks everyone.


----------

