95 Nissan Pickup brake issues, Help iM desperate!

BONFIRE99

MEMBER
1995 NISSAN TRUCK

Hi, I have a 95 NIssan Pickup two wheel drive, four cylinder. I recently replaced a broken brakeline and bled the system, but no pedal. I tried gravity bleeding the system with all bleeders open with the truck level. Then I pressure bled the system again to no avail. This morning I replaced the master cylinder with a reman. I bled the cylinder on the bench and then installed it, gravity bled the system, then pressure bled, still no pedal. When the truck is not running I can pump up a good pedal. If I take my foot off for a minute, the pedal is dead again. When the truck is running, there is absolutely no pedal. I can't imagine that there is air in the lines because I have gone through two large bottles of brake fluid and bled the system at least six times. Also, when I pump the pedal and crack the bleeder, the fluid comes out with force with no air sputters. There aren't any leaks, I checked all the wheel cylinders and lines. No dripping anywhere. Can anyone please help me? I'm desperate. Thanks in advance.

1 Reply

SERVICE WRITER

MECHANIC
9,123 POSTS

The bleed procedure is Left rear, Right rear, left front, right front, r-abs actuator. ( Did the r-abs get bled?)
Sometimes following thier specific procedure make the difference. Use gradual, slow pressure and return.

It sounds like either the master cylinder tht was replaced may be defective or possibly air is coming back into the system.

I question the master cylinder for a couple reasons. When you lose a pedal and it hits the floor, the master cylinder can be damaged. Thus the replacement. Re-man masters are not always the most reliable ones. You can check the master by plugging the line recepticles after removing the line from it. The pedal should be hard.

I have had bleed problems where air comes back into the line, but doesn't leak fluid out. Why I don't know, but I just know what happens. We were able to narrow it down to the bad line/wheel sector because it did give air.

I would open the bleeders and see if any bubble come out, next check the adjustment of the brake shoes they could be way out.