Thread: abs ,non abs master cylinder info and questions

hey guys.
I got a new project and it was built/modded by someone else,so I have been searching a bunch trying to figure out whats up with the brakes on this car.It was equipped with factory ABS but it is disconnected(not sure if this is part of my problem or adding to it,or what)
Setup now is
-z32 front/P10 rear
-NX MC is 4 port like non abs,but 2 ports are plugged.


Heres the issues/details...
-The pedal almost hits the floor before starting to grab.
One pump,and the pedal is good,and the car stops pretty well....I figure this is just because the 4 pot Z32 brakes need a bigger master cyl like the U13/altima one.
No problem,I have one

So I started gathering the tools and whatnot to swap the MC.After looking at the car again,I noticed the car has had the abs disconnected as mentioned above.
Basically there are 2 ports being used and 2 are blocked off now.The abs pump is not plugged in,and the abs dist block is still on the firewall.I have not traced to see what lines are still being used.

I guess my question is whether I can just plug the same 2 holes on the U13 which is also a 4 port,and call it a day?
How does plugging ports effect the braking system?

or...are some of my problems being caused by the abs being disabled rather than removed and replaced with nonabs part/lines.etc.

Either way I want the U13 MC on it,but should I wait until I can remove the abs completely,or give it a try like it is and see what happens?

The person who built the car has done some great work in other areas on the car,so I am hoping that he actually has this working properly,even though the abs pump and other parts are still installed.Just lloking for some insight and opinions on this situation.

nvmind

I would think that it would have to do with the fact that the pump and distribution block is still in the system; as the fluid has to push through a "dead" pump before it can pressurize the calipers.

Thats a good point ,and something I was considering....I would have thought the nx MC would be fine ,but it is 4x the pistons up front too.
Trying to remove the pump,and whatnot will not be fun with the engine in there...Maybe the U13 will hellp get me part of the way there and at least make it a little better until I can remove the abs system entirely.

My stock nx brakes will outstop this setup all day as is,so all it does is make it hard to fit wheels at this point.

I think you mis understood.They arent fading after one brake...they need one pump to get normal each time you brake.The first time the pedal goes almost to the floor and it does stop but its not very confidence inspiring,thats for sure.
I plan to put ss lines on with the U13 MC since I had all these parts laying around anyway.

Have you tried bleeding the brakes? I could be bad or a lack of fluid that is causing the issue. Oil does not compress so it does not matter how long the lines are, just that there is no air in the system. Basically what you are doing is using the brakes without ABS activated, just like any other car with ABS. The ABS module only turns on when it senses that one or more tires are locked up, then it activates the control, other than that the fluid is still going through the ABS block.

If you do not want the ABS i would pull it all out and run new lines (B14 non ABS lines work great), and use a 4 port MC as you mentioned. I bet once you swap everything your problems will be gone.

Remove the intake manifold to remove all the ABS stuff.
That's the only way I could do it on my NX.

OHHH so you need to BUILD pressure to use them normally, not that your lose pressure after a brake. So basically you can start the car just sitting in your driveway, pump the brake pedal once to the floor, and then it returns and is fine the rest of your trip, until you shut the motor off again?

remove abs pump
run new lines
use all 4 lines on BMC
bleed

Def bleed. Go get some Genuine Nissan Heavy Duty fluid from the dealer, about $8/bottle and they have it in stock.