What am I missing?

[Art@NissanSport]

Ok, I've replaced the wheel cylinders, put good working calipers up front, replaced the master cylinder, put on steel braided brake hoses, bled the car (240Z) three times now. Seems to be a good flow of fluid with no air bubbles, etc., etc., etc.

The brake pedal still feels soft. I know the brakes are working because when you hold the pedal down I can't turn the discs or drums. I know it's been a while since I've driven a Z but I don't remember the pedal being that soft.

What I'm I missing?

[hls30.com]

Have you

1) bled the master Cyl before bleeding at the wheels.

2) Verify the Master Vac operation(check the vacuum going into it(Pump the brake pedal and see if the idle changes when you do), and that the diaphram isn't leaking)

Will

[Arne]

Also make certain the rear brakes are properly adjusted.

[Art@NissanSport]

I think the pass side rear brake could use more adjustment. But would that make the pedal soft? If it does, then I know thats the problem. I'll be doing that tomorrow.

Yes I did bleed the MC first.

The car is up on jackstands on all fours. Easier to bleed the brakes that way. Not in a position to start the car yet to test vacuum, but should be able to right after adjusting the rear brake.

Thanks

[hls30.com]

You probably have a small vacuum leak, just enough to bleed down when the car is off, power brakes don't work with out vacuum.

Will

[BR-Z]

I think the pass side rear brake could use more adjustment. But would that make the pedal soft? If it does, then I know thats the problem. I'll be doing that tomorrow.

I had the same problem, and adjustment of the rears fixed it. The vac leak could also contribute.

How does it feel while driving? Is the softness an issue that you notice then? Does the power assist feel about right?

[Art@NissanSport]

I haven't been able to drive it yet. I did test it once for 1 block and went right back to the house. Brakes sucked, but main reason was carbs are not fine tuned yet and the car ran like crap. Idles great, ran like crap. I'll get to that as soon as I get the brakes figured out.

The more I think about it the more I think its the rear drum-pass side. The other three are tight when the peadl is down and the one drum can still be moved with force.

I thought I adjusted it, but I guess not enough.

[code3z]

Do you have the front calipers on the correct side? The bleeder valve should be at the upper side of the caliper. If the bleeder valve is on the bottom, air will not bleed out properly and cause an air bubble to form in the caliper.

[geezer]

I can't think of anything to add to the responses, other than after sitting overnight, all the minute air bubbles you might not have noticed or removed will have come together and you should bleed the system again.

[Mat M]

All that has been mentioned is good, but (not many know this) if your car is an S30, the rear DRIVER side line is actually longer than the pass. side. The next time you bleed the brakes, start on the DRIVER side REAR, and work counter-clock-wise around to the driver front side.

[Arne]

All that has been mentioned is good, but (not many know this) if your car is an S30, the rear DRIVER side line is actually longer than the pass. side. The next time you bleed the brakes, start on the DRIVER side REAR, and work counter-clock-wise around to the driver front side.

Ahh! Very good, Mat. I hadn't given that any thought, but you're right. We should start at the LR on an S30. Excellent tip!

[Art@NissanSport]

Ok, I think its done. Considering all the hours that I've worked on Z's the past 20 years, you think I would have noticed the front calipers reversed (nipple down instead of up). So I switched them, adjusted the rear pass drum and bled the brakes one more time. The pedal no longer goes to the floor and everything seems normal. The true test will be when I test drive the car. Hopefully this weekend. I still have to adjust the carbs.

Thanks for all the help and I'll find a way to mention you guys in my next article on the 240Z project car (Fall 2007).