300zx brake problem on a s13 help!

[Flip240sx]

ok so i was happy that i finally got my z32 front brake conversion i bleed a four calipers and when i test drove the car the pedal goes to floor and no brakes i have to pump the brake 3 times for the pedal to get hard but stops great what could be happening here everytyhing was working fine with my stock caliper but after the swap it started doing this they told me it could be my MC or BB but why if every thing was fine b4 please can somebody give an awnser this ..i would really glad thanks guys

[numbnuts240]

did you also install a z32 bmc?

[Samurai C]

Sounds like a master cylinder. With the car off pump the pedal till it gets hard and hold your foot on the pedal. If it sinks to the floor than its a bad master. Check for any leaks as well. I'm not sure but I think you need the Z32 master because the caliper is bigger and you need to move more fluid into it, but I would search that first.

[Flip240sx]

no i have the stock mc and ive used the 300zx lines and checked for leaks..

[Flip240sx]

i dont think you need to upgrade to the z32 mc ive seen post around saying is not required ..

[johnny butt]

i dont think you need to upgrade to the z32 mc ive seen post around saying is not required ..

nonsense, it is the most logical reason you are having the problem that is occurring now. your S13 master cylinder isn't designed for four pistons per caliper.

The LEAST you could get by with on an S13 is an S14 master cylinder, but I would still get the Z32 master cylinder.

[Flip240sx]

it not nonse my friend as a s13 and changed nothing but the front caliper and rotors with the stock mc and works great ..i just dont get why mines didnt come out that way..

[Flip240sx]

samurai i did what you told me with the car off and nope the pedal stay hard and dosent sink to the floor..

[johnny butt]

well if it happens to be something else that's causing that problem... let us know.

i haven't swapped on my 300zx calipers on the front yet but I planned on getting the z32 Master cylinder since it is only like a 50$ part and a worthwhile upgrade for something you are dependent upon in stopping your car in any instance (saving your life?).

50$ > your life?

[Flip240sx]

ya ima go buy the 300zx mc today and hope that fixes my problem i hate driving with suppose biger brakes that dont brakes when i want em too

[johnny butt]

ya ima go buy the 300zx mc today and hope that fixes my problem i hate driving with suppose biger brakes that dont brakes when i want em too

yeah i know, just don't cheap out on parts that are crucial to saving your car and your life.

if the new MC has the same problem after a proper bleeding, let us know.

good luck.

[dlydrvn240]

When you were bleeding your brakes how does the pedal feel? Did you get increased pedal feel as you continued to bleed? You did install the calipers with bleed screw at top correct?

I would recommend a re-bleed...then after you are content with your bleed job have a buddy try to spin the hub while you have the pedal pressed in. If its not spinning give it another whirl and see what happens...hopefully the problem is solved and you had some addl air in the lines. If it doesnt spin freely and the brakes seem to be working but you still dont have brakes then I would also check the MC.

I am assuming the Brake Fulid level has not changed since you did the inital bleed and refilled as neccessary...if it has you def have a leak somewhere so start digging.

[Flip240sx]

no trust me i did a lot of bleeding rear,right ,rear left , front right and front left 3 times and yes the pedal is super hard i hold the pedal and the disc dont spin the brakes work great with the car stoped but if drive over 10 mph the i sinks to the floor i tried holding it stops but reall slow but if i pupm it 3 time the pelda get hard and boom car stops on a dime im still tripping why is it doing that after the swap

[94_240sx]

Just to make sure. All the bleeders are on top, right? Hard and soft brake lines might be clogged too. Rear left is the longest brake line, not rear right. Try gravity bleeding then. Open all the bleeders and let it seat like that for a while and bleed one by one.

[Clawhammer]

Don't forget to bench bleed the master.

[94_240sx]

Don't forget to bench bleed the master.

I've heard 240 BMC doesn't required bench bleeding. I didn't bench bleed mine and it worked just fine. If you press the pedal, you can see the bubbles coming up and eventually it stops.

[tEknoS13]

weird. I usually get some fittings weld them shut and then screw them into the master cylinder, if you pump the pedal and it goes down then your master is gone. same pricipal as samurai i guess.

the stock 240 master cylinder is just fine, no need for z32 upgrade although it will help with the pedal feel

[hungryjoseph]

it really sounds like there are air in your lines. have someone pump the pedal and look at the resevoir in your master cylinder and see if there is any tiny air bubbles or fizz. if there is, you need a new one, or there is a leak in your lines somehwere. but if the pedal holds pressure when you pump it, it is ussualy an indication you didn't bleed it right.

[dlydrvn240]

I agree with hungry....and really check for leaks where you used your conversion lines for the calipers...both at the caliper and at the hardline. Also were your calipers apart for any reason (powder-coating)?

It will take quite a bit of bleeding to get all the air out with putting in new lines and calipers.

But like everyone else said if the bleeder is at the top, and you have bleed properly, and have no leaks....i would lean towards the MC.

[94_240sx]

check the leak around pistons too. You could have bad seals too.

[Flip240sx]

checked the lines hard and soft ive checked the pistons and i paint them put didnt put em apart and yes the both bleeder screws are on top but still why would my mc go bad after it was working just fine after the swap

[tEknoS13]

any of the hard lines kinked? (im sure i mispelled that word)

[fast_s13]

sounds like you need to bleed the brakes alot more..it takes ALOT of bleeding to get all of the air out

[hungryjoseph]

you either didn't bleed them right, or you didn't bleed them enough, which in that case means you didn't bleed them right

[Flip240sx]

no i think i did plenty of bleeding six times at least but everthing is ponting to the bmc ima go but it and see how it turn outs cuz it cant be my booster right?

[hungryjoseph]

if you have a junkyard near you, i would go there and pull an MC tehre and try that out

[SR24DET]

I vote for master cylinder.

As far as bench bleeding goes.... I dont believe in it. I have replaced my clutch master 4 times. I beat the piss out of it with Clutch kick. Anywho 3 times i just installed it and blead the entire system and it worked fine. The forth time my buddies like, "You have to bench bleed that thing." So I did and it made no difference.

IMO bench bleed = BS

But im not sure about the BMC. But on the same point. Whats to stop air from flowing through it when you move it from the bench to the car?! Humm...

[Flip240sx]

by the way this may sound dumb but how do you post pics i havent been in this site for a while .. i wanna post pic of my mc so you guys can tell if is good or not thanks ..

[i240sx]

photobucket.....

[ddgsxr504]

Upgrading to a Z23 MC is NOT required. If the one you have is bad then go ahead and get one since you need a replacement anyway.

The brakes are vaccuum operated via the booster, are you sure you don't have a vaccuum leak or faulty booster?