Brake problem 1990 Nissan Maxima.

[dougmccurley]

I just got a 1990 Nissan Maxima. The brakes would work and then the pedal would go to the floor sometimes. I changed the front brakes and bleed the line. they still work sometime and go to the floor other times. could there air in the lines still? Dirt in the lines? or master cylinder.

[loystock]

Your car is unsafe so keep it off the road until the brake is fixed.

Did you bleed all the brake lines or just the front? Was the brake pedal hard to pump during bleeding or not? If it is spongy, then you have air in the system and you need further bleeding. Ensure that the reservoir never goes empty during bleeding.

Check for leak in your brake lines. Pump the brake multiple times. If you have a major leak, the level of fluid in reservoir will drop. Small leaks may be difficult to find. You need to take a closer look into each brake component - master cylinder, ABS actuator (if equipped), calipers, etc. If system has no air nor leak, then most probably it's the master cylinder - worn piston cup (seals causing fluid to leak by when braking.