300ZX Brake Swap/5-lug

[PabloHoney]

Ok, I did a search, and a couple posts said that I needed 300ZX front spindles/hubs and others said I just needed the S14 SE front spindles/hubs. I have a base 4 lug right now. I am getting the S14 SE rear hubs and rotors, 300ZX front calipers and rotors, and whatever I need for a front spindle/hub set. Also, does anyone know the exact fittings I need so that I don't have to buy the damn stainless ones from PDM for $100 (biggest rip-off ever).

[PabloHoney]

no no, if they were stainless lines I wouldn't be bitching, but it is merely a fitting that adapts the fittings on the caliper to fit the 240 lines (from what I have read).

[PabloHoney]

So does anyone know if I need the front spindles off a 240sx SE or the 300zx? Also, has anyone upgraded the master brake cylinder? Does one off of a 300zx work or not? Thanks again.

[danejah99]

check out the new sport compact car mag, they are doin this swap on project silvia right now.

[R240NA]

So does anyone know if I need the front spindles off a 240sx SE or the 300zx? Also, has anyone upgraded the master brake cylinder? Does one off of a 300zx work or not? Thanks again.

You do NOT need spindles. Unfortunately, this is one of the most abused topics on the 240. For a base model S14, you only need the 5 lug hubs, NOTHING else. The spindles are the same for all S14s and are only required on S13s. You then need either S14 SE 5 lug rotors, Z32 rotors, or you can have your 4 lug rotors redrilled. The Z32 MC will work, but there are 2 issues. The first is minor, the plug on the level switch is different, you need to either cut your plug off and add spades, or get the Z plug and hardwire it. Secondly, all Z32s are ABS equipped, so the MCs, whether it's a 15/16, 1", or 17/16, all have only 2 line ports. The 3rd one is capped off and there is no flare fitting inside of it. The right way to make it work is to remove a fitting from your old MC and put it in, some people don't go that route and just screw the line in without a fitting at all. Some aftermarket MCs have the fitting in it, but it's a guessing game of which one. OE and OE reman units will not have it at all.

[jdubau55]

is there ayplace that makes an aftermarket MC for the S13. because with 4 pots from a Z32 i would think you would need more fluid volume to the caliper to make it an effective swap.

[R240NA]

is there ayplace that makes an aftermarket MC for the S13. because with 4 pots from a Z32 i would think you would need more fluid volume to the caliper to make it an effective swap.

You would think that, but it's not really a neccessity. The Z32 wil bolt up to either S13 or S14, and the older S12 VG models will work as well. I have Z32 brakes at all 4 corners, the pedal feels fine. A switch to an automatic S14 over a 5speed MC would be easy too, it's 15/16" vs. 7/8".

[mojo22]

i would think that once the required volume of fluid had been filled in the calipers, lines and reservoir....that pressure would be more of a concern than volume....it is not as though you are getting more movement out of the pistons in the calipers

[PabloHoney]

You aren't getting more movement, you are simply having more volume to fill behind the pistons. There are four pistons up front on a 300zx caliper vs 1 on a 240 caliper. 4 pistons (even if they are a bit smaller) take more fluid to move the same distance as 1. Check out http://www.howstuffworks.com/brake.htm if you don't understand the concepts behind it.

[mojo22]

i looked at howstuffworks...but i didnt' really see anything that i didn't have a basic understanding of, or anything that really seemed like it was minute technical info. i won't say there aren't little nuances that i don't understand, but here is my thinking about the whole thing....and i am probably not right. Pressure and volume are related....volume is not what is going to move the pistons and pads, pressure is. as volume goes up, pressure goes down. now, the internal volume of the 300z caliper is going to be greater, so i guess that means pressure would drop throughout the the line.........anyway, what i was thinking is that the pads don't really move but like a tenth of a mm anyway, so the displaced volume is very very inconsequential.....IMHO that is. i think the real key is the amount of clamping force on the rotors themselves....i.e. pressue. the four piston calipers allow for more clamping force and surface area of friction on the bigger rotor. the pad has a bigger footprint on the rotor. much like having wider tires....they have a larger contact patch on the groud...more friction...better traction. so, once the volume of the caliper has been filled, i guess the need of having more volume will cause the pressure to go down? so, does going to a larger Master cylinder mean it will have a larger bore....i.e. more fluid volume moved per stroke of the piston in the MC......fluid is displaced....volume goes down...pressure goes up. or am i just overthinking this? that was a rhetorical question.

[PabloHoney]

i looked at howstuffworks...but i didnt' really see anything that i didn't have a basic understanding of, or anything that really seemed like it was minute technical info. i won't say there aren't little nuances that i don't understand, but here is my thinking about the whole thing....and i am probably not right. Pressure and volume are related....volume is not what is going to move the pistons and pads, pressure is. as volume goes up, pressure goes down. now, the internal volume of the 300z caliper is going to be greater, so i guess that means pressure would drop throughout the the line.........anyway, what i was thinking is that the pads don't really move but like a tenth of a mm anyway, so the displaced volume is very very inconsequential.....IMHO that is. i think the real key is the amount of clamping force on the rotors themselves....i.e. pressue. the four piston calipers allow for more clamping force and surface area of friction on the bigger rotor. the pad has a bigger footprint on the rotor. much like having wider tires....they have a larger contact patch on the groud...more friction...better traction. so, once the volume of the caliper has been filled, i guess the need of having more volume will cause the pressure to go down? so, does going to a larger Master cylinder mean it will have a larger bore....i.e. more fluid volume moved per stroke of the piston in the MC......fluid is displaced....volume goes down...pressure goes up. or am i just overthinking this? that was a rhetorical question.

Ok, a few things to point out. Pressure and volume are directly related yes. But, the reason you fill your brake cylindar with Brake Fluid instead of simple, cheap water is because water will compress when pressurized (not very much, but it does) and brake fluid does not. Of course, water also boils at a lot lower temperature also, which is another reason. So, the overall volume of the FLUID will not change, the volume of the system will only change. SO, if you have more volume to fill, you need a larger bore cylinder. This is because if you have a small bore filling behind a small piston it's great, but if you have a small bore filling behind 4 pistons then it takes a longer pedal stroke to displace the fluid. That's why you bump up to a larger bore brake cylinder.

Now the point about the pads, friction and rotors. Believe it or not (and most of you will argue this to death), surface area has nothing to do with friction. I will say it again....SURFACE AREA HAS NOTHING TO DO WITH FRICTION. Think about this before argueing though. Friction is defined as follows:

frictional force = (coefficient of friction of surface/object)*(Normal force of surface on object)

In other words, no where in this equation do you see area, volume or any other measure of distance. I know what you are gonna say: "Why do wider tires give better traction?" I asked my physics professor this. What's he say? Something along the lines of more rubber compensating for imperfections in the road. I dunno exactly what he is getting at, but this is how it is, according to University Physics by Reese/Brooks/Cole. I still don't fully believe it myself but if someone can tell me where surface area is untroduced, I would love to hear it. It would put my mind at ease =)

[SR180SX]

has anyone upgraded the master brake cylinder?

try S14, or S15 master brake cylinder, not sure if Z32 will fit, I found one S15 at my local junk yard

[PabloHoney]

You found an S15 at a local junkyard? That must be quite a junkyard!! Are you sure you aren't talking about the MC S14 (97-98)?? Just wondering.

And Lost_To_A_K-Car, thanks for the explanation...where did you get this information? I don't doubt you, I just like to have facts rather than **** that most people just spew off that they think they know. Bigger brakes give better stopping force because they are basically a bigger heatsink. They dissipate more heat away from the pad, so that the pad does fade.

[mojo22]

i am sorry if you thought i was spewing, but i guess i take forgranted some basics facts in most equations. thanks to LOST to K car for laying some of that down. fluid is compressable, but not to the extent that air is, that is why air in your brake lines causes major problems. but larger rotors and bigger pads provide more clamping force due to the amount of friction available. like K car said...HIGH SCHOOL PHYSICS. and some common sense. sorry for not being able to quote, but i haven't learned all the great tricks of BAD### posting. what he said about tires is true, that is also why when your street tires wear down you don't have the same amount of traction you once did, but for a different reason. in that case, the tire compound is harder (less friction) b/c they want them to last longer, and the treads actually provide more contact force on the ground, rather than the amount of pressure being spread out across the whole contact patch. its the whole BED OF NAILS trick. you can't lay down on ten spikes b/c there is too much pressure per nail, but if you have 100 nails, the pressure per nail is a tenth of what it would have been, therefor just bareable and most likely not skin peircing.

my common sense also says that larger diameter rotors allow for more leverage on the stopping device. the larger diameter allows for the point to point on a rotor to be father apart as it travels around, so more cooling time as it makes it around and more leverage b/c it is biting on the outside of the device. it has been said "i can move the world if you can give me a lever big enough" for those who have not paid enough attention to what a big part leverage plays in everyday life, go out to your car, get a lug wrench and grasp is right next to the socket, and try and take a lug off. then move out a few inches.....then out, and out....and see that it will get easier the further out you move down the shaft of the wrench. that is leverage. with bigger rotors if you can imagine that the radius of the rotor is your lever, the radius being drawn from the center of the hub to the brake pad and caliper. the further out you are, the more effective force you will have.

ok, i still can't get past the fact that so much more brake fluid would be displaced when upgrading brakes that a new MC would be needed. for the miniscule amount of fluid that will be displace the pistons in the calipers, i just can't see the need. i will gladly take some sort of textbook info, or some type of information on the subject that details the need for it. or just the preference for it. telling why and how much....some numbers on how much volume difference there is would be great.

[PabloHoney]

And Lost_To_A_K-Car, thanks for the explanation...where did you get this information?

Um, that's high school physics, dude.

I don't doubt you, I just like to have facts rather than **** that most people just spew off that they think they know.

I don't spew.

Bigger brakes give better stopping force

Say it three times:Bigger brakes do not make you stop faster.Bigger brakes do not make you stop faster.Bigger brakes do not make you stop faster.

The ultimate threshold of vehicle slowing ability is the coefficient of friction between the tire and the road. If you can lock up your brakes - and you can on any modern car - then you're getting everything you need out of your brakes. Going to a larger setup will not decrease your stopping distance one iota, and anyone that tells you different is trying to sell you something.

because they are basically a bigger heatsink. They dissipate more heat away from the pad, so that the pad does fade.

I'm sure you meant "does not fade".

This is true, and this is the reason for larger brakes.

Brakes convert kinetic energy to heat. That's their job. If your brakes can absorb more heat before boiling the fluid (thus fading), then your brakes are "better".

Unfortunately, my guess is that 90% of the 300zx brake upgrades are performed by people who never drive in a manner that they actually experience fade, and are thus completely unnecessary.

All right, first off, I am not argueing that you are wrong, I just want to know where you got your information. Give me a source besides that you learned it in high school from your teacher. Yes, I meant does not fade, typo. About bigger brakes making you stop faster, I never said that. I know that they do no make you stop faster, I said they give you better braking force. In other words they absorb more heat, which is what you all ready stated. So basically, I just want you to give me some rock hard information from a book or website that is reputable. I have taken three years of physics (and yes, most of it in college), and I have never seen evidence of this.

I don't know about the rest of you with 240's but my opinion is that the brakes suck cack. I have had them fade on me numerous times on the highway (in town they don't). That is my reason for doing the upgrade.

[SR180SX]

question, if size don't matter then why faster or bigger car has bigger rotors??

[mojo22]

well, if you get bigger brakes and more stopping power, you need to get wider tires with more grip so that you can harness the stopping power. shall we call it REVERSE HORSEPOWER? if you need wider tires to keep traction with more horsepower for acceleration, you can also use the increased grip to handle decceleration.

oh, and a proportioning valve would be a good thing to think about when going with a custom brake setup.

[PabloHoney]

I said it was high school physics, as in "This is so simple, you should really just know it". I didn't say I learned it in high school.

Nonetheless, since

Frictional Force = Coefficient of Friction * Contact Force

Contact Force = Force / Contact Area

isn't self-evident enough for you - and after three years of physics it really should be - here's the first link Google came up with, and the second.

I realize that surface area affects friction, the reason I started the rant about it is because i have never had anyone explain exacly why without just saying "because it does" or some other bull****. And, no, in the three years of Physics that I have taken, friction was never explained to me with surface area involved. So, again, I thank you for the excellent explanation (although in a rather insulting manner).

Also, what's with this:

question, if size don't matter then why faster or bigger car has bigger rotors??

Testosterone, mostly.

Now you are saying that bigger rotors don't help, or are you just saying that most people are putting bigger rotors on for show, rather than for function?

[SR180SX]

You found an S15 at a local junkyard? That must be quite a junkyard!! Are you sure you aren't talking about the MC S14 (97-98)?? Just wondering.

Yes, I was luck find a S15 Front Clip at my local junk yard!! got the great deal for the booster!

[AunVoh]

Yes, I was luck find a S15 Front Clip at my local junk yard!! got the great deal for the booster!

:bsflag

[SR180SX]

:bsflag

NO BS... got it from Jay's Auto Wreck at CA, Iwindel, who has container every 2 weeks from JP,

[AunVoh]

why does he have s15's sitting in a junk yard?

[SR180SX]

why does he have s15's sitting in a junk yard?

like i say, he has container from Japan almost every 2 weeks or so.. I found a S15 front clip but engine already sold!! he has lotz of JDM parts!!

[SR180SX]

check out the S15 booster