300z brake swap gone wrong

[amolao]

How is going boys?

Just completed a front 300z brake swap with the following:
1 1/16' mc remanuf.
S14 auto brake booster
26mm caliper/rotors

The first time, my brake pedal went straight to the floor, all lines and mc free of air. The fluid in reservoir turn black and after many times bleeding the brakes still no brakes. Gave up and decided to get another mc suspecting bad seals due to the black dark color the fluid turned during the road test.

Second time: after getting another mc and going thru the same process, the result was the same. Brake goes all the way down the first pump, only in the second pump the brakes actually are engaged. After the road test, found the mc to be leaking from the breather hole between the ports. Is my booster killing my mc's?
Is this mc bad now, I've done many brake jobs before and never ran into these issues....

[LeD ippen]

when changing to new mc you need to bleed it when its not on first or you run the seals dry and kill them. the box should come with a bleed kit 2 fitting and hoses

[float_6969]

Yea, I was going to ask the same thing, are you bench bleeding it before you install it?

[amolao]

Yes, mc was bench bled accordingly....it took a while but I made sure was air free....

[amolao]

Recheck all my steps again and still no brakes. I went ahead and swap my original booster (manual, S13) back into the system, all of a sudden now my pressure goes up and it locks the brakes driving down the road. By the way my brake pedal sits, I can tell that both boosters are aligned differently. Something tells me that is the aligment of the booster. Does the longer size of the z 32 MC justifies having to adjust the booster "nipple" out to engaged the pistons in the mc properly versus the shorter 240sx mc setup??
I tried searching, but most commons issues people have is with air in the lines, calipers upside down,etc....

Thanks for any input you can provide...

[amolao]

Problem solved:

2 issues were causing all my problems. The alignment of the brake booster was one. Second, was my rotors not properly aligned with the hub. THe holes drilled were not properly enlarged to allow the rotor to sit flat against the hub, even though it look like it was. This is very critical and even the smallest spacing caused by the rotor hanging on the lugs will make your brake pulsate and squeal very loudly.

[Razi]

Glad you figured it out!

[95zenki man]

Sorry to thread jack but are you running any spacers razi?? Also whats your rear tire size? Im stuck between 225 40 and 215 40...