300zx Brakes. If you have them, POST HERE!

[Jeff240sx]

This thread was inspired by a post in another thread. I just didn't wanna hijack the other thread, so here's mine.

Originally posted by Tyler Durdan
Quick question:

Is your brake pedal real mushy feeling? I just put mine on, and have bleed the fronts pretty damn well, and the brake pedal feels incredibly mushy...I know it's the norm for them to be mushy feeling, but I don't know if it's supposed to be this mushy. Any thoughts or suggestions would help.

I have always wondered why people have mushy brake pedals from a z32 swap. So I figured that if we put our minds together, we can figure it out.

First off, my setup is on a s14 (1996)
Calipers:1991 z32 TT calipers. Aluminum, 30mm.
Rotors: X-drilled and slotted Brembo rotors.
Pads: EBC Greens and currently Hawk HP.
Lines: PDM-racing conversion lines.
Master Cylinder: Stock

As far as mushyness goes, it's not at all mushy. I have only bled my lines once, and that was during the install.

I am also against using a z32 Master Cylinder, because it was setup for a z32, and not a 240sx with a super-heavy front bias in braking. It is usually required to swap all 4 calipers to use a z32 MC safely.

If everyone else could post their setup, and mushyness level, and we can (hopefully) figure out a solution or cause.
-Jeff

[Foxcolt]

26 mm Z32 brakes. Stock modified lines (To cold to put right one's on) Brembo blank rotors.

Little bit mushier than stock. Not something that was noticable enough to not like. No biggie

[Dousan_PG]

mine:
30mm TT front brakes
stock z rotors
earl's SS brake lines
oem pads (?)

rear: stock
KVR pads

mine are slightly mushy but not HORRIBLE. i have to add my rear ss lines still but fronts are SS lines, stock z rotors and i dont know what kind of brake pad (oem?). anyways, i like it how it is. if its too firm it can be TOO responsive. especially on the track. idont want to lock up the fronts when i just need slight slowing down. i like them how they are. more pressure means moer braking power. slight pressure just slows it down a bit, which can be perfect depending on situation.

[Foxcolt]

I did notice how easy it is to lock up the fronts. I deffinatly don't like that.

I do think the z32 MC is a good idea. That's what I plan on doing once I get my rears in. Fooking drum brakes...Hate em

[Tyler Durdan]

91 300zx front aluminum calipers
front 30mm Stock Rotors
Stock 300zx Lines
OEM Pads
Mushy as hell.

One thing I'm noticing is the ss lines...maybe that's the solution to my problem. I'm gonna bleed the rears to see if it cures the problem. I'll let you know.

On a side note, thanks to Jeff for the start of this thread.

Mark

[brage]

I installed mine, and the mushyness factor is VERY low... A common problem is people installing the calipers upside down (with the bleeder screw at the bottom as opposed to the top which causes problems. There have been numerous posts regarding this on twinturbo.net!


SO... MAKE SURE YOUR BLEEDER SCREWS ARE ON THE TOP OF THE CALIPERS WHEN INSTALLING THEM!!! otherwise it is nearly impossible to bleed the top half pistons!

-jeff

[Tyler Durdan]

Bleeder screws are installed on top...my thought is the air got into the system during the install, and somehow made it's way through the rear brake lines...so I'm gonna give those a bleeding to see if it cures my problem.

[uiuc240]

You always have to bleed ALL brakes...not just the fronts. When you do the swap, the lines get disconnected...that's all you need for a reason to bleed all the lines.

I have:

26mm calipers, KVR pads, SS lines, KVR rotors, Russell speed bleeders.

My pedal is very firm except for the bit of play at the top of the travel...and I'm used to that now. I *do* want the rear brakes and a Z32 MC, though.

Eric

[Kid Zelda]

Set up on an 89 S13

Z32 front Aluminum 30mm calipers

Z32 rear Aluminum calipers (Also, I think all rear Z32 calipers are aluminum, does anyone know if Nissan changed the material to iron, when they changed the front calipers to iron ? )

Rotors are brembo blanks that need to be replaced soon
Pads are OEM Nissan pads

SS custom brake lines.

Need to bleed the brakes a bit more, but the pedal feel is a bit mushy. I only drove the car around the block, since I just got the car running ;) :D


Can't wait for Z32 M/C, new rotors and good pads :)

[AKADriver]

I've noticed that noone is mentioning if they have ABS or not.

It makes a difference... there are different stock master cylinder sizes.

AFAIK:
'89-'96 non-ABS: 7/8"
'89-'96 ABS, '97-'98 all: 15/16"
300ZX: 15/16" and up (most are 1")

The 15/16" master cylinder should be a-ok. The 7/8" might be a bit overworked...

For those who want a M/C upgrade for your non-ABS cars using 300ZX fronts and stock rears, a '97-'98 non-ABS M/C might be the ticket.

ABS and non-ABS master cylinders have a different number of ports and won't swap...

[brage]

I have ABS+VLSD BTW

-j

[91s13coupe]

is this upgrade really worth it??? you only get 8ft greater (60 to 0) stopping distance than the stock setup. my guess is if you by some quality crossdrilled/slotted rotors, some good pads and stainless steel lines you would get similar results (if not better) for alot less $$$$. plus a floating caliper setup has more stopping power than an equivilent fixed caliper setup. im not flaming anyone who has done this upgrade just trying to justify the price difference. to me it just seems like a "bandwagon" fad. sorry if i piss anyone off, thats not my intent!

[AKADriver]

Stopping distances should really be completely unaffected. I can lock 'em up from 70mph with the stock brakes equipped with even just decent pads.

The main benefit isn't stopping power, but the immense heat sinking capability of the bigger pads and rotors.

The extra stopping power and definitely the extra heat capability come into play when you have sigificantly more power than stock and you take your car to the track.

The S14 Silvia K's and S15 Silvia Spec-R came equipped with "300ZX brakes", stock...

[240 2NR]

There's more to brakes than simply, if you can lock them you don't need anymore. The feel from the 300zx brakes is inspiring, drive some and then decide, I think you'll be convinced. Sure, the stock brakes are competant, but they still leave room for improvement. A sportier pad helps and once warm I find the KVR's pretty amazing though they still fall behind the Z brakes. I think the larger rotor and stronger caliper allow for greater modulation in addition to the heat capacity it adds (which may or may not get utilized). Either way there is room for improvement in the stock system, you may not need it, but the Z's are a very "affordable" and easy upgrade.

[hooter]

Originally posted by 91s13coupe
is this upgrade really worth it??? you only get 8ft greater (60 to 0) stopping distance than the stock setup. my guess is if you by some quality crossdrilled/slotted rotors, some good pads and stainless steel lines you would get similar results (if not better) for alot less $$$$. plus a floating caliper setup has more stopping power than an equivilent fixed caliper setup. im not flaming anyone who has done this upgrade just trying to justify the price difference. to me it just seems like a "bandwagon" fad. sorry if i piss anyone off, thats not my intent!

I use the stock S13 brakes with good pads and good fluid with no problems so far. Have yet to experience any brake fade.

It really depends on how you drive. Some people swear by the 300zx upgrade, some can live without it. I personally don't think I could live with the mushy pedal and would want to upgrade the MC while I'm at it, which adds to the cost and complexity of the swap.

-Charlie

[91s13coupe]

thats my point. usually when i do somthing (especially when it comes to my 240) i do it right. so money is just not a factor when it comes to my car. if i have to wait to do it right because it costs more, then ill wait! but unless you seriously race your car im not convinced its worth the $1000+ dollars to convert to 300zx brakes (w/ mc, etc). granted i havent driven a 240 with the conversion,so i may be dead wrong but it just seems like alot of people are doing it cause everyone else is! and a good majority of those that have spent the bucks DONT race their cars (legally). for a potent STREET machine(or even a weekend warrior scca solo racer) i think its overkill and money that could be spent better elsewhere!

[Jeff240sx]

Ok. How about we don't hijack this thread with crap. Start a new topic in chat.
I started this thread to figure out why some people had a mushy pedal and others have a very firm pedal, minus about 1/4" of softness at the top.
Also, where did you get the distance of 6'? Is that some imaginary number to try to make a point? AFAIK, nobody has done a 70-0 stop series with stock brakes, then swapped to z32 brakes, and done a comparison 70-0 series.
And what the hell is a "floating caliper setup?" I unbolted the 240sx calipers from the 2 bolts holding them in, and installed the z32 brakes in those same 2 bolts. The calipers are installed very much the same. Are both "Floating calipers?"
It's also not $1000+ for the conversion. I did my fronts for $450, and the rears can be had for $250. The MC is a junkyard item, or AutoZone. Most people only do the fronts, but even the whole setup isn't near $1000.
Finally, brakes are the most important aspect of any sports car. I don't car about what races you participate in, or anything like that. If you drive fast, or even modify your car for more power, you need brakes.
-Jeff

[91s13coupe]

sorry we got "off topic" but i said 8 ft and actually the project silvia in i think sport compact car had a braking comparison between the stock 240 brakes and the 300zx upgrade (they did front and rear 300zx brakes) and the stopping distance was "only" 8ft less 60-0 than the stock 240 brake setup! and the 240 uses a floating caliper setup while the 300zx uses a fixed caliper setup. search and you will find an explanation of each. that little "bar" that you have to remove to do the upgrade(its called a torque member) that surrounds the calipers on the stock setup is the major component of a floating caliper setup (which are proven to be more efficient than a fixed caliper setup) because that component basically multiplies the clamping power of the brakes by providing some leverage for the caliper. sorry for the off topic stuff but i was just voicing an opinion for what its worth. im not flaming anyone for doing the swap just pointing out there are viable options without having to drop all that $$$ on the conversion!

[mrmephistopheles]

8 feet is an eternity when you REALLY want to stop.
Like Jeff said, brakes are the most important aspect of a sportscar. I add a caveat to that: Tires are the most important aspect of a braking system. You can have either stock or Brembo brakes, but if they're stopping a skinny 15" tire, it's gonna suck.
Big, wide wheels and sticky tires are not just for bling factor.

[SlowEXd]

93 NON ABS

fronts
26mm Z32
Brembo slotted
brembo pads

rear
stock calipers w/ Brembo slotted, and Brembo pads
Stainless lines all corners

Mushier than stock! Not firm enough for me.
I have bled more times than my driveway can handle,(always a little splatter)

1" Z32 master cylinder going on hopefully this weekend.
Keep you updated.

[Tyler Durdan]

Fixed the mushy problem with my setup...91 300zx fronts only.
When I bled the rear lines, there was a lot of air trapped inside. I have about a 1/8 - 1/4" of mushiness, then it's firm. I absolutely love the setup...as for the price issue...be patient and shop local junkyards. I did my entire setup for less then $200.

91 300zx calipers and rotors pulled at local junkyard: $80.00
Rotor Turning and new oem pads: $42.00
Brake fluid: $6.00
New Seal Kit for DIY Caliper Rebuild: $24.00
Total Cost: $152.00
Being able to stop constantly with no brake fade: Priceless.

Granted you can add another $100 for ss lines I'm gonna pick up, but it's still a cheap and damn good brake upgrade. An extra eight feet stopping distance is a hell of a world of difference at scca events, especially when one turn that leads right into another, and then into a sloam.

A fast car only needs a throttle...fast drivers need throttle, brakes, clutch, and a steering wheel. Quote me on that.

[Jeff240sx]

WOOT! I helped someone with this thread!
-Jeff

[Tyler Durdan]

Originally posted by Jeff240sx
WOOT! I helped someone with this thread!
-Jeff

Boowah...damn we are post whores.

*Hangs head in shame*

[LanceS13]

IIRC, SCC said their car had a rear bias (locking the rears before the fronts). If they get the proportioning right and make the fronts work harder than the rears like they're supposed to, I bet they'll cut another 10ft.

[AKADriver]

The proportioning was messed up IIRC because they were using a 240SX master cylinder with 4 wheel Z brakes.

I'll have to go back and reread the article... did they do the test of the stock braking system with fresh high-performance pads and good tires or with the worn-out stuff? I know their 300ZX brake upgrade also included a 5 lug swap with Volk GT-Ns and sticky rubber.

[LanceS13]

I'm pretty sure it was all old stock stuff. But I think they had some Spec V 17x7" wheels (assuming decent tires) on it before the GTNs. I'd like to see what happens with the Z MC and maybe a decently tuned adjustable proportioning valve.

(Sorry Jeff, I know this isn't exactly what this thread's about)

[Halz]

The SCC project car changed tires and wheels at the same time it changed brakes.. If they could lock up the wheels with the stock brakes, the 300ZX brakes would not be able to improve upon that.

[Jeff240sx]

Sure you can... The initial force 300zx brakes create is much, much more than the 240sx brakes. This means that in less pedal travel, you generate much more clamping force. And why does everyone insist that the first stop that you make should be the shortest? Sure, shorter is good, but repetition is much better. The main reason for the 300zx brakes. Initial force and fade resistance. It's not complicated people!
-Jeff

[91s13coupe]

but dont you get increased fade resistance and heat dispersion from a cross drilled and/or slotted rotor in the factory issue size?!
i bet its right there with the 300zx coversion except in the MOST EXTREME instances! which 95% of us here will never see!

[uiuc240]

cross drilling is for aesthetics ONLY. if you don't believe me, ask those who race. pads are either outgassed from the factory or made from non-gassing materials (which was the main reason for drilling in the first place). the MINOR addition of surface area for braking does not outweight the loss of material for heat absorption/radiation.

i have cross drilled. i won't get them again. extra money for basically nothing. but they DO look cool.

Eric

[nismo270r]

Well, cross drilling does occur in some racing applications, but it is done to reduce the weight of the rotors. Slotting is what you usually see in race applications to aid in venting.

As for my Z brakes I have:

Aluminum TT Calipers
SRSwap.com Conversion Lines
Porterfield R4S Pads
Rears are stock with Metal Masters Pads

Pedal is quite mushy. I want to see what happens after I rebleed the system again. I've been talking to Alex Samardzich from www.importnut.net about doing the Z32 master cylinder with only the front Z brakes. I'm thinking about attempting it in the future, but I've got other things to worry about right now. From what he told me, his pedal feel is much like a german car now. About 1/4" of free play at the top, then it bites. Exactly what I'm looking for. But he also has the rear Z brakes. I don't know if I want to go through all of that though.

Originally posted by uiuc240
cross drilling is for aesthetics ONLY. if you don't believe me, ask those who race. pads are either outgassed from the factory or made from non-gassing materials (which was the main reason for drilling in the first place). the MINOR addition of surface area for braking does not outweight the loss of material for heat absorption/radiation.

i have cross drilled. i won't get them again. extra money for basically nothing. but they DO look cool.

Eric

[240 2NR]

Originally posted by Halz
If they could lock up the wheels with the stock brakes, the 300ZX brakes would not be able to improve upon that.

That's only partly true.

To cite an example, my old 88 mazda 626 could lock it's wheels, but I guarantee the braking system left a large margin for improvement.

Braking is a series of events that must happen together. Simply locking your brakes and skidding your tires actually creates less friction than being at the edge of lock up, so technically if you are locking up your brakes you are wasting braking potential. This is why braking is not simply mashing on the pedal, but rather a squeeze. You don't want to surprise the tires, you want to squeeze on the brakes because when coasting the weight distribution is around 50/50. As you begin to decelerate more weight shifts forward. If you slam on the brakes, you only use the traction avaliable with 50% of the weight over the front tires and therefore, lock up is much easier (less resitnace to lock up and no modulation to find the limit of adheasion) than if you modulate the brakes and apply more pressure as more weight transitions forward.

This is why brake balance and modulation are just as important as ultimate stopping power. Done right, the Z brakes should offer all these attributes, plus increased fade resistance.

[gregsr20]

would sell ya some but to you that would be considered advertising, contact WeSt

[Halz]

I have not been persuaded..

Two cars otherwise the same, one with 240SX brakes, and another with 300ZX brakes, thresh-hold braking, should achieve very similar stopping distances (well within 8-feet of each other).

Up until a point, the 240SX brakes are just fine.. this 'point' would be up until the driver could no longer lock up the tires from exceeding the thresh-hold braking limit.

Granted, with the two similar cars stopping from 120mph with 'Raybestos' pads (really bad pads), the larger [heat capacity] rotors and calipers of the 300ZX setup should prevent the Raybestos pads from fading sooner.

With the arguments so far, one might draw the conclusion that even on a rain-slicked road from 25mph, the ‘otherwise-equal’ cars with different brake setups, the 300zx-equipped car would stop sooner..

[240racer]

Originally posted by gregsr20
would sell ya some but to you that would be considered advertising, contact WeSt

sell me what? I think you can post things for sale in the for sale section and then it's not "advertising"
why do I need to contact West??

[240racer]

Originally posted by Halz
I have not been persuaded..

Two cars otherwise the same, one with 240SX brakes, and another with 300ZX brakes, thresh-hold braking, should achieve very similar stopping distances (well within 8-feet of each other).

Up until a point, the 240SX brakes are just fine.. this 'point' would be up until the driver could no longer lock up the tires from exceeding the thresh-hold braking limit.

Granted, with the two similar cars stopping from 120mph with 'Raybestos' pads (really bad pads), the larger [heat capacity] rotors and calipers of the 300ZX setup should prevent the Raybestos pads from fading sooner.

With the arguments so far, one might draw the conclusion that even on a rain-slicked road from 25mph, the ‘otherwise-equal’ cars with different brake setups, the 300zx-equipped car would stop sooner..

we are not trying to say that the brakes make the difference when stopping from 25mph on a wet road. That is almost 100% tires. However, if the front to rear proportion is wrong, then that will drastically affect your wet stopping ability. If the rears lock first you spin and if the fronts lock first then the rears are not contributing properly to stopping.

the debate comes when you have multiple 100-20 (or so) stops. If I braked from 100mph down to 20mph and then sped back up to 100 and tried to stop, my pads would certainly be over temp and fade. However, if I had nice "stock" rotors and good race pads, I could probably handle 2 stops from 100-20 in a row, but the third would be too much. Now if I had the 300zx brakes, I could probably handle a few more (don't know how many) Racing involves stopping as fast as you can and then speeding up as fast as you can so you can stop again. That's why you need god brakes. This single stop from 60mph crap is the most worthless test I have ever heard and anybody who thinks that it means anything I do not trust for information. Actaully it's not THE most worthless, the top gear accel from 30-60 that one of the mags does is THE most worthless, but the braking one is a close second.

[drifterx]

i used stock S13 brakes and pads and i got alot of brake fading especially when i raced really hard. 1 time i smelled the burning of the pads. now i got Xdrilled rotors (stock size) and i dont have the fading problem but i am not track racing either.
the 300zx upgrade is great in terms of having no brake fading problems.


Originally posted by hooter
I use the stock S13 brakes with good pads and good fluid with no problems so far. Have yet to experience any brake fade.

It really depends on how you drive. Some people swear by the 300zx upgrade, some can live without it. I personally don't think I could live with the mushy pedal and would want to upgrade the MC while I'm at it, which adds to the cost and complexity of the swap.

-Charlie

[AKADriver]

Try adjusting your braking technique.

It sounds like what's happening to you isn't so much fade as glazing. You're likely braking early with less pedal pressure... in effect 'riding' the brakes and not so much heating up the brakes as keeping them hot long enough for the pad surface to glaze over. The crossdrilling helped you because it's slicing/sanding the glaze off. Crossdrilling doesn't do a damn thing to reduce heat in a passenger car brake system.

[Jeff240sx]

Originally posted by AKADriver
Crossdrilling doesn't do a damn thing to reduce heat in a passenger car brake system.

Why has the word "heat" been brought up so many times? This isn't a hard concept. The friction generates heat in brakes, which are absorbed into the rotors themselves. This is why rotors are dual plate with fins between them. To sink heat. And the larger the surface area, and metal across (width), the greater the heat capacity. Then the air comming by, either through the rims, or from behind, will cool the rotors, and the fins between the plates will cool them also.
Then we have brake fade. This happens for 2 reasons. 1) The pads and rotors are too hot to absorb more heat, so you don't stop. This solution to this is above. 2) Offgassing. This is something that is many times better today than it ever was. The pads will flake off, and heat the trapped air between the rotor and caliper. Heated air will expand, pushing the pad off the rotor, reducing stopping ability. The solutions designers found years and years ago was to give places for the heated air to go. These were slots and cross-drills. And they do help, at the expense of rotor surface area, and strength. You will always have the trapped gas problem, but not nearly as bad, thanks to technological improvements in brake pad material over time.
So.. can we please stop saying that slots and x-drills cool brakes.
-Jeff

[thx247]

Originally posted by Jeff240sx
Why has the word "heat" been brought up so many times? This isn't a hard concept. The friction generates heat in brakes, which are absorbed into the rotors themselves. This is why rotors are dual plate with fins between them. To sink heat. And the larger the surface area, and metal across (width), the greater the heat capacity. Then the air comming by, either through the rims, or from behind, will cool the rotors, and the fins between the plates will cool them also.
Then we have brake fade. This happens for 2 reasons. 1) The pads and rotors are too hot to absorb more heat, so you don't stop. This solution to this is above. 2) Offgassing. This is something that is many times better today than it ever was. The pads will flake off, and heat the trapped air between the rotor and caliper. Heated air will expand, pushing the pad off the rotor, reducing stopping ability. The solutions designers found years and years ago was to give places for the heated air to go. These were slots and cross-drills. And they do help, at the expense of rotor surface area, and strength. You will always have the trapped gas problem, but not nearly as bad, thanks to technological improvements in brake pad material over time.
So.. can we please stop saying that slots and x-drills cool brakes.
-Jeff


No. Brake fade occurs for different reasons.

Brakes take the forward energy of the car, and use friction to convert it into heat.

All components of the braking system are susceptible to heat (obviously). All brake pads have a heat coefficient. At a certian temperature they have a certian amount of grip. Generally as pads heat up they lose more and more of their avaliable grip. Its just like tires, as tires heat up over a certian temperature, they begin to lose grip. Racing brake pads have a higher heat coefficient, which means they work better at hotter temperates than normal pads do. The downside of that is race pads normally cannot get to operating temperature on the street because your not braking hard enough and often enough to raise their temperature to the point where they work well.

Pads can also get so hot that they actually begin to burn and melt, but by then brake fade is the last thing on your mind....you should be looking for a nice place to crash.

Fluid can fade because it begins to boil. When it boils bubbles form in th lines and gas bubbles are compressible! Its just like having air in your brake lines.


People use the 300z rotors because they can disapate heat faster. This allows drivers to be on the brakes harder while on the track. People also use them because they look cool.


Areas that I have not elaborated in are left that way intentionally. *grammer...bah i dont care that much

[Jeff240sx]

Man. Why would you say NO, then agree with me? Didn't I cover your whole brake fade post in my first section? Yes, with the exception of the brake fluid part. But this is a 300zx BRAKE SWAP POST, so fluid would have nothing to do with a difference between 240sx and 300zx brakes, unless you swapped to DOT 5+.
So.. how about we keep things back onto the 300zx brake (letting all things be equal, as in same fluid, same pads) and discuss why or why not have a 300zx brake setup.
-Jeff

[thx247]

I was commenting on your post about why fade occurs. It was inaccurate. The only reason to swap is for the added fade resistance a larger braking system offers. There is not other reason. (it even adds unsprung weight =( )

[Halz]

Any piece of mis-information is worth a reply that can offer clarification or broaden the discussion, thereby in effect adding to the overall 'maturity' of the discussion at hand.

What seems to be chronic of any discussion is that people are not willing to correct another's 'facts', or find faults in what information they have to share.. When someone reads that information, which is new to them, they take it as fact, and might just mention it again somewhere else. I'm sure many can agree that all Canadian 240SX do not have LSDs, however, questions like this come up time and time again.. It becomes annoying, even.

With that, DOT 5+ brake fluid has no reference.. I believe it was DOT 5.1 you were referring to; the non-silicone base brake fluid that is very different from DOT 5 silicon base fluids.

Edit: spelling

[Jeff240sx]

Ok. I knew exactly what I was talking about. I simply didn't remember the name. I didn't wanna research something that I already was well-aware of, yet didn't know if it was 5.1 or 5.01 or 5.11, or whatever. So I made the broad, general statement DOT 5+. Can't people figure things out without writing a book on why they are correcting?
And can't I make the point (because that's what this whole damn post is, making points) about the brakefluid boiling to cause fade is something that has no importance in 240sx vs. 300zx brakes... because we can only have so many variables, so why not keep the fluids the same.

Finally, since everyone needs to correct people, I'll do the same miserable pick the post apart tactic.

Originally posted by Halz
With that, DOT 5+ brake fluid has no reference.. I believe it was DOT 5.1 you were referring to; the non-silicon base brake fluid that is very different from DOT 5 silicon base fluids.

It's not "non-silicon based" fluid. It's Poly Glycol Ether based brake fluid. And actually, DOT 3, DOT 4, and DOT 5.1 brake fluids are all Poly Glycol Ether based. The only exception is DOT 5, which is a Silicone, or Silicium-based Polymer fluid, depending on the brand.
DOT 5 brake fluid should never be used as racing fluid, because of the inherent compressibility of Silicone. Also, silicone is also non-hydroscopic, so a little water will layer with the silicone, which will reduce the braking abilities of the fluid, and heat much faster. The heat will turn the water directly into steam, which will add air to the system, and cause all sorts of hell.
Poly Glycol Ether based brake fluids will mix with water, and are uncompressable. Water will reduce the boiling point of the fluid, but won't cause hell in the system.
I know my crap, and didn't wanna write a book on brakefluid. Can't everyone have a brainfart every now and then?
Also... CAN WE GET BACK TO 240sx vs. 300zx BRAKES NOW!?!?
-Jeff

[killjoy]

I was going to put the MC from my s14 but the number of ports for lines are different cause my s14 was ABS. But I looked on my friends s14 non abs and it wouldn't work either. So does a MC from a z31 or z32 work. It has to have 3 ports for lines to work in the s13 that I have.

[sykikchimp]

I believe we need to hear more about WHO has ABS and Non-ABS systems with their 300zx calipers. All you guys who already posted your setups, please include this info. :)

If it appears that the guys with ABS have very little mushy pedal, and the guys without have mushy pedal, then I think we're on to something.

a 97-98 15/16" 240sx MC might be the trick for all us NON-ABS folks out there.


I personally still have the stock brakes. (NON-ABS)
I run:
Porterfield R4S pads
Brembo blanks
SS lines
ATE Super BLue fluid

THAT **** WAS $$$. basic brake upgrade for ~400.. a little more and I could have had a comparable setup with 300zx calipers. Of course if the non-abs, abs MC situation pans out the way I think it will, I'm glad I haven't switched yet. I still plan to do it. I just think I'll modify my plans to include a 97-98 240 non-abs MC

[Jeff240sx]

I'm running non-abs w/o a z32 MC, and I have an extremely firm pedal. My set-up is the first post in this thread.
I'm thinking that pads or lines have something to do with it.
-Jeff

[nismo270r]

Here's my setup again...and I do have ABS AND a mushy pedal:

Aluminum TT Calipers
SRSwap.com Conversion Lines
Porterfield R4S Pads
Rears are stock with Metal Masters Pads


I'm going to re-bleed the system again, and see how much that helps here soon. Just waiting on some parts to come in. Figured I might as well replace some worn pads while I'm in there...

[Jeff240sx]

Does anyone know what the srswap conversion lines are made out of?
Is there a possibility of flex in the line based on materials? I know that the PDM lines have an extremely flex-resistant inner line, with a small diameter steel jacket.
I'm starting to think that brake line flex is determining the mushyness of the pedal.
-Jeff

[sykikchimp]

Originally posted by Jeff240sx
Does anyone know what the srswap conversion lines are made out of?
Is there a possibility of flex in the line based on materials? I know that the PDM lines have an extremely flex-resistant inner line, with a small diameter steel jacket.
I'm starting to think that brake line flex is determining the mushyness of the pedal.
-Jeff

this is all assuming everyone on the board knows how to bleed their brakes properly.

[Tyler Durdan]

I think the lines are could be the problem solver.

I have:
91 z32 Aluminum Calipers
Stock Rotors
OEM Pads
ABS 97 240
Stock Lines (z32)

Little bit of a mushy pedal, but the system was bleed properly and pedal is not that bad. I think when I change over to ss lines, they will cure the mushy problem.

[Dream240]

I'm reviving this thread cause I need some help and I think I might be able to solve my problem from what I've read, but I have a couple questions.

I have: 96' s14 non-ABS
Front: DOT-3 fluid, Stock MC
30mm calipers
Brembo blanks
Hawk pads
SS lines
Rear:
Stock calipers
Brembo Cross/slotted
PBR pads
SS lines

My problem, NO pedal!!! I've bled ALL four lines AND the MC and yet I still have NO PEDAL!! After reading the posts I'm unsure about the whole bleeder screw on the top as opposed to the bottom. The bleeder screw is on the lower side of the inside caliper piece on both front wheels.
Isn't this where it needs to be? As far as there being air in the top of the caliper that won't escape when bleeding, is this true? I thought if it's a pressurized system then no matter where the air is, it'll eventually be pushed out? Is this wrong?

Also just for info, I've bleed each wheel until there is a steady stream of fluid flowing and still no luck. Anyone help!!!!

[ultraprince]

yes i have z32 front brakes, ss brake lines, and yes a little mushiness.

[formeRiceR]

bleed bleed bleed....

if that doesn't work you MC might need to be replaced. My M/c quit on me right after the brake swap.

I have :
4 Pot- Calipers off a JDM s14 K (same as the 300zx Brakes) 30mm Iron
SS lines
240sx MC
Brembo Blanks
Project Mu Pads

Stock rears....

a lil mushiness but other than that perfect...

[Tubed4evr]

After reading the posts I'm unsure about the whole bleeder screw on the top as opposed to the bottom. The bleeder screw is on the lower side of the inside caliper piece on both front wheels.
Isn't this where it needs to be? As far as there being air in the top of the caliper that won't escape when bleeding, is this true? I thought if it's a pressurized system then no matter where the air is, it'll eventually be pushed out? Is this wrong?


The bleeder screw must be at the top of the caliper to be sure all of the air gets out of the system. You have the left and right calipers reversed my friend. A very easy mistake to make. The air can still float through the system even if it is pressurized. Switch the the calipers and hopefully your problem will be solved.

Ryan

http://importnut.net/240pics/brake_upgrade/brakeswap099.JPG

[brianglawson]

i have sme but cant install them till i get new wheels:( http://images.cardomain.com/member_images/3/web/411000-411999/411958_105_full.jpg

[Dream240]

The bleeder screw must be at the top of the caliper to be sure all of the air gets out of the system. You have the left and right calipers reversed my friend. A very easy mistake to make. The air can still float through the system even if it is pressurized. Switch the the calipers and hopefully your problem will be solved.

Ryan

http://importnut.net/240pics/brake_upgrade/brakeswap099.JPG

Yeah I'm sure that's my problem. Thanks for the tip. I'll let you guys know if I get it working.
Hey brianglawson did you get those calipers powder coated or are they painted? I painted mine with the G2 painting kit from MVP motorsports, it's okay, kinda rough cause you have to brush it on. I'm actually thinking that buying some high gloss high temp paint would have looked better. I'll leave it for know but I might just redo it with the spray on paint. Looks good man!!

Thanks guys for the tips. And sorry for reviving and old thread but, at least it good to know that this is still helping guys out there.

[brianglawson]

i used duplicolor 1000 degree ceramic engine paint... just it was the best red i found, none of the orangish red ford/chevy red crap, just a nice pure bright red, then i just block sanded the "NISSAN"

[Jeff240sx]

SS lines doesn't make any sense here. The original point of this thread (I know, since I made it) is to determine why some people have mushy brakes and others don't. SS lines could mean ebay lines, pdm lines, stock upgraded 240sx lines, earls lines, ect.
I do have an automatic tranny MC, which I've heard is larger than manual.. but anyway
I still think the problem lies within the brake lines used. Cheap or 240sx lines has given many people a mushy pedal. People with the PDM lines in general don't have issues, and their pedals are firm as a rock.
-Jeff

[FinalDrive]

I'm running stock 240sx lines with no mushy pedal feel at all. Here's my setup:

'96 SE non-ABS
26mm front z32 brakes, stock pads,
stock rear brakes/pads
stock brake lines
z32 1 1/16" MC

Pictures of the MC:

http://images.cardomain.com/member_images/10/web/394000-394999/394662_72_full.jpg

http://images.cardomain.com/member_images/10/web/394000-394999/394662_73_full.jpg

[thx247]

I have also run stock lines with 140k on them using ATE fluid and experienced no pedal fade or "mush" on the track. This was with stock and 180sx brakes.

I think a majority of the mushy pedals out there are resultant of peoples inability to bleed their brakes properly.