i was doing the 300zx caliper conversion then i found out that my calipers don't clear my wheels so i put the stocks on and i started bleeding the lines and the car won't keep the pressure and won't brake then i bled the lines 2 more times and still nothing i didn't touch anything besides the calipers so what could have gone wrong????????????

 

bump..............

 

Just asking the obvious, but you've checked the fluid levels right?

What was the bleeding procedure you used? Bleeding brakes can be tricky, and one little mistake can cause issues.

Did you tighten all the fittings and make sure the stock hardware was installed? I can't remember anymore, but I'm pretty sure the 300ZX fittings are different.

 

i checked the fluid ,vacuum,lines for leaks, and stock fittings were installed and bleeding the brakes is pretty straight forward in that order RR LF LR RF engine on and hand brake off so i dn't know, could it be the brake booster or the master cylinder and how you chech if they are ok

 

You still have air.

Bleed them better, take your time and pump lots of nice clean fluid through it.
Always close the bleeder valve while the brake pedal is held on the floor.
You should use at least a whole pint of fluid just to bleed the rear.
Tap on the calipers with a small hammer to release any trapped air pockets.

 

i used 3 bottles of brake fluid to bleed them , i'm going to try to tap the calipers and see,, i really doubt it will change anything but i'll give it a try thnx, oh how about the master and the booster !any ideas

 

Master gets bleed when you bleed any line.
The booster doesn't cause a lack of pressure, it only causes a very hard pedal.