Nissan 240SX Performance Modification/Brakes
There are many brake upgrades for the 240sx. Bellow is a list of them and the process of putting them together.
Stock brake spec and known compatible replacements 
Front options for S-chassis
s13 USDM ('89-'94) rotors are 252x20mm (non ABS) or 257x22mm (with ABS)
180SX/Altima rotors are 280x22mm
Z32 rotors are 280x 26mm or 30mm
rear options for S-chassis
S13 - 10" non-vented rotor, smaller single piston caliper, integral handbrake
S14/S15 - 10" non-vented rotor, larger single piston caliper, integral handbrake
A31 Cefiro - 10.5" vented rotor, smaller single piston caliper, drum handbrake
J30/Q45 - 11" vented rotor, larger single piston caliper, drum handbrake
Z32/R32 - 11.75" vented rotor, 2-piston caliper, drum handbrake
General notes on brakes 
When considering upgrading brakes several factors tie in to the end result. An often overlooked function of a braking configuration is the bias. Brakes should not be upgraded in front or rear only. Rather, the amount of applied braking torque should be increased proportionally front and rear for appropriate feel/bias (e.g. 6 piston front brakes with stainless lines up front and stock pads/lines in the rear can actually decrease overall braking performance).
I cannot emphasize enough how important bias is in a braking setup. Just being able to lock-up your front tires easier does NOT mean you are now able to stop quicker!!
All the parts need to be considered in a braking setup to determine if its right for you!
Master Cylinder 
If you get a larger or smaller master cylinder then for every inch of pedal travel more fluid will be pushed through the lines. Don't just go buying a random larger MC without knowing the specifications, as these have internal valving that determines brake front and rear bias which will severely impact your braking performance.
There are many aftermarket pad companies that produce sport oriented brake pads. There are many different materials a pad may be comprised of, each having its own individual properties. This will impact dust creation & color, rotor & pad wear rate, and A very important thing: EVERY PAD HAS A HEAT RANGE. This means the pad will ONLY function optimally within a given set of temperatures. OEM brake pads are usually designed to function well in very cold temperatures to moderate braking. When you have had several large hard stops they heat up to a certain point and get out of their range causing the pad to not have the same braking torque and "glaze" the surface. Glazing is a condition in which the properties of the outermost contact layers change and it essentially polishes the mating surface, decreasing the normal grip levels. This is PERMANENT damage to the pads! There is a wide range of compounds from stock all the way up to full race. Note that a pad designed for full race will NOT grab sufficiently during daily street driving and you will be unable to stop normally! Get a pad that suits your driving environment and/or style. If you are going to the track, consider using 2 sets of pads and swap them out at the track.
Rotors in a braking system do 2 things. They act as a heatsink so they absorb heat when you brake, and dissipate it normally from air moving over them. The larger the rotor, the more the metal. The more the metal, the more heat can be absorbed during braking and the more fade resistance your car will have. Stock brake rotors are "blanks"; this means that they are just a flat surface. This is the surface your brake pad will mate to and provides the largest total available clamping area per revolution. There are several different variations of the standard brake rotor; some of them are often misunderstood and aren't quite as relevant today as they once were.
'''Slotting:''' Doing this to a brake rotor does have benefits, but is more visually appealing than beneficial. Slotting a rotor provides angled slots along the surface that exist to help wipe the pad surface clean on every pass. This ensures a fresh pad surface at all times and it does in fact help protect a pad against fade since it always scrapes off the top layer. It also helps with water and debris evacuation. There are several problems with slots however that outweigh these benefits. One of them is the fact that part of the brake pad is not in contact with the rotor at any given time. This means a lower total square inch area of friction material doing what its there for - applying braking torque. If part of your pad isn't touching, then what's the purpose of it being there? Another issue is with the manufacturing process and physical properties. A slotted rotor is thinner in some areas and although more structurally sound than cross drilling, it still weakens the rotor by providing. This makes the rotor more prone to warping. Another problem depends on if you get a more "economy" production. This means the fresh blank gets churned out in high numbers by a shop that isn't doing it for a quality name but the almighty dollar. In turn, they are cut too hard and too fast by the machine making metals first heat treating an uneven distribution. Its heat treated around and in the cut but the areas nearby don't get hot enough so the isolated spots modified the grain structure of the metal permanently but not all of it. This will also make them more prone to warping. Another problem with slotted rotors is they can tend to create an undesirable pulsating pedal feel by nature. The level is application variant (i.e. larger or more numerous slots translate to more pulsing).
'''Cross drilling:''' Cross-drilling a rotor is a practice adopted probably 50 years ago when the materials for a braking pad were mainly a crude organic base. These pads when heated would produce a gas that would get trapped between the pad and the rotor and making a cushion of air between the pad and the rotor. Cross-drilling was created to give the gas an area to escape through. MOST MODERN RACING PADS ARE DESIGNED WITH DIFFERENT METALLIC MATERIALS THAT ALMOST NEVER PRODUCE MORE THAN A FINITE LEVEL OF GAS. This means that cross-drilling a rotor is no longer needed in 99% of applications. Because of the previous need and the stylish benefits these are still widely sold and people are very misinformed on their need. Cross-drilled rotors have a large amount of metal removed and suffer the same problems of slotting. This metal is not in contact with the pad so that is less overall available pad contact surface area for braking torque. This also means less metal available to absorb heat, essentially functioning as if you had a smaller rotor. Also similar to slotted roters, production of cross-drilled rotors can be problematic if they are drilled too fast, causing the initial heat treating to be in isolated spots, and modifying the grain structure of the metal permanently. Another issue is when drilled, a rotor may receive microscopic cracks in the surrounding area. This can cause severe issues, perhaps to the point that a rotor may actually CRACK IN HALF! If you feel you must have cross-drilled rotors for looks, don't get "economy" versions. The best quality cross-drilled rotors have the holes actually CAST or FORGED into the rotor and have a much lower loss in structural integrity.
Brake Lines 
Braided stainless steel lines are a great upgrade for any brake system with rubber lines. OEM brake lines tend to be a very soft rubber that expands slightly when pressure is applied. The expansion rate is not linear however so the impact on pedal feel from having them won't be either. Stainless braided lines have the metal reinforcement to deter expansion and result in a stiffer, more linear feel. When purchasing lines, consider those with a plastic or similar outer sleeve protector. This way if rubbing occurs, it wont wear through the stainless braiding, maintaining the integrity of your braking system.
Brake Fluid 
Using quality brake fluid is very important for any performance-oriented driver. There are different classifications and rating systems by the department of transportation that determine the minimum dry and wet boiling temperatures. The higher the boiling temperature, the more likely you are able to resist high heat braking without gassing out the lines. Boiling brake fluid introduces air pockets instead of fluid which compress when pressure is applied vs the fluid. This means the pedal might sink to the floor but any line pressure isn't getting to the caliper! That can be very dangerous, and you can tell if your brake fluid is getting to the point where its been boiled by looking at it. fluid appears white if it has ever boiled and should be changed.
Dry / Wet boiling temp
DOT 3 401ºF 284º F POLYGLYCOL ETHER BASED FLUID
DOT 4 446º F 311º F POLYGLYCOL ETHER BASED FLUID
DOT 5 500º F 356º F SILICONE BASED FLUID
DOT 5.1 518º F 375º F POLYGLYCOL ETHER BASED FLUID
Dry boiling temp is the fluid in its virgin state. Wet boiling temp is the fluid + 3% water by volume.
Dot 3,4, and 5.1 are all inter-mixable without any negatives. Dot 5 fluid is silicone based and cannot be mixed. Silicone fluid has its ups and down. It is non corrosive to paint unlike normal brake fluid, and it doesn't mix with water so its boiling temps stay the same (actually a negative) Since it doesn't absorb the water the water stays separate. No brake system is completely sealed and will always absorb water. If the system absorbs water but it stays separate you will have 2 fluids, one of them with a very low boiling point (bad) Silicone fluid also has more compressibility by nature and will cause a more "spongy" pedal feel.
Fluid sold in metal cans absorb water far less than plastic cans while on the shelves. A good common practice would be to change your brake fluid once every 6 months when your car sees a lot of "spirited" braking, And bleed them well every change to be sure there is no air in the system. Bleeding before/after track events is a good idea to be sure your brakes are optimal for the event and you didn't boil your fluid during.
When upgrading your brake system a larger caliper may be used to provide more braking torque. There are several deciding factors with caliper choice that impact the overall effectiveness. Increasing the overall piston diameter will distribute the braking force over a larger area and generally provide more clamping force whether going to a larger piston than stock in single piston designs, or migrating to a multi piston setup. Bigger and more doesn't always mean better however. Too much braking torque for your setup might mean you can lockup the tires from just tapping the pedal, and making an "on/off" feel impossible to modulate.
Choose a caliper appropriately sized for your tires and application used (just because you can lock all seasons doesn't mean you can stop efficiently on r-compounds) Caliper mounting brackets determine the pad and caliper clamping location on the rotor. Think of it like a torque wrench... The farther out you brake the more torque you can apply to stop the car and the more overall surface area the pad will contact in 1 full revolution. It may be a sufficient enough upgrade to just get larger rotors and relocate your calipers/pads farther out by extending the bracket.
Speed Bleeders 
An often overlooked part of the brake system is the installation of speed bleeders. These do nothing for performance, but everything for sanity. They make it so you can bleed the brakes efficiently and by yourself. All you do is crack them a 1/4 turn and pump away. there is a bearing inside the bleeder that every time you let off the pedal is returns in to stop air from coming in as well. Very worth while thing to do, epically if you plan on track racing your car.
Stock Upgrades 
The stock 240sx front brakes are single piston units with 9.8" ventilated rotors. The rear is a 10.2" rotor and a single piston caliper with an integrated e-brake. These brakes are sufficient for most people and with appropriately upgraded pads/fluid/lines. Rule of thumb if you can lockup your brakes then a larger brake caliper is not needed for the speeds and tire compounds your using. These brakes are more than adequate for daily driving and some track use, but once your start doing some serious racing you will need to upgrade parts appropriately to handle the heat and to avoid the dreaded brake fade. The stock brakes will be great for spirited driving and light track, But research your options and decide on an upgrade appropriate to you. Several factors need to be considered. Something with larger rotors is needed for more repetitive stops, and something with a larger amount of clamping force is needed if you are not able to push your current tires to the locking point (while using pads with an appropriate heat range).
Z32/Skyline Front Brakes 
By far the most popular brake upgrade for the 240sx. The stock brakes on the 240sx are fine for autocross and track days on stock power, but as soon as you get more power and start attaining more straight away speeds you are going to want to upgrade to big brakes to handle the heat and to help avoid brake fade. Skyline brakes are almost identical, but do come with some small variations in width. Also some JDM S14's came with 300zx brakes from the factory. Another note about z32 brakes is that they are bigger so wheel clearance can be a problem. Only 7 spoke S13 alloys sometimes clear. S14 stock wheels will clear z32 brakes, You can shave off the Nissan lettering on the outside of the caliper to gain more clearance, and you can also run wheel spacers to also help with wheel clearance. But remember about your wheel offset when using wheel spacers.
Parts Necessary 
You will need the following parts to make the Z32 front brakes work on your 240sx.
There are many different versions of the Z32 brake calipers. There are some that are aluminum and some that are cast iron. There are some that accept 26mm wide rotors and some that accept only 30mm rotors. 26mm aluminum calipers were only used on 1990 non turbo model 300zx's. 30mm aluminum calipers were used on 1990 twin turbo and all 1991-1992.5 300zx's (turbo and non turbo). 30mm iron calipers were used on all 1992.5-1996 300zx's. The best way to see if you have aluminum or iron is with a magnet. Obviously if its aluminum a magnet will not stick to it.
There are many different rotor designs to choose from, but make sure you get the rotors to match your calipers. You can get slotted, cross-drilled or both on the same rotor. These features help with the heat dispersal by giving you more surface area, although they do eat away at your pad quicker than blanks. The 300zx came with 5 lug wheels as well as 5 lug rotors. This is not a problem for S14 SE's because they all came with 5 lug stock, but for us S13 guys there are 2 options.
Conversion lines are necessary for doing the conversion. SPL parts sells them for a very reasonable price. The fitting going onto the caliper is different from the stock style. The stock fitting is a banjo style, and can be made to work with an appropriate adapter, otherwise z32 brakes will need 10mm Inverted Female (IF) flare fittings. Also steel braided brake lines are recommended because they help with brake feel and also don’t fail like stock brake lines can.
Installation is very straight forward. Remove and replace everything and bleed the system of air. The only tricky parts is the removal of the dust shields. The stock dust shields are designed for stock rotors, and since the Z32 brakes are so much bigger they must be modified/removed. You can either take the whole set up apart and remove them completely or simply cut them so that they are out of the way, the choice is yours.
Z32 Rear Brakes 
The stock rear brakes on the 240sx are single piston with an integrated e-brake. The Z32 rear brake set up is comprised of a 2 piston caliper, an 11.6" rotor and a separate drum e-brake. The swap can be difficult, but it does help complete a total braking system.
Parts Necessary 
The rear calipers from any z32 will do, but once again make sure that they match your rotors.
These come in many designs similar to the front rotors, and the same 4-5lug solutions apply.
Other Parts 
You can directly bolt on the rear brakes the same as the front if you wish, but you will not have an e-brake. The only part that is not bolt-on is the hydraulic line, which requires a different fitting on the caliper end. Solutions can be had from local shops that make custom brake lines or from online shops that specialize in the 240SX, and stock the necessary lines. To make the e-brake work you will need the Z32 rear drum assembly and the e-brake cables. Some people have used the Z32 aluminum uprights, but it is not necessary and requires the use of different rear lower shock mounts.
For the 240SX you will also need to get e-brake extension cables. If you can find them, R33 cables are long enough without extension.
s13 can use the 300zx ebrake cables no problem.
You need to remove the stock calipers and remove the spindle from the control arm. Also unbolt the axle so that you can get the spindle free from the car. Remove the hub from the stock assembly and put the new splash shield/ z32 e-brake assembly onto your hub. After this is complete reattach the spindle to the hub assembly. Run the e-brake cable through the sub-frame towards the e-brake handle, and then reattach the spindle assembly. Put the caliper back on, attach the brake lines, attach the e-brake cables, bleed the system and you're done.
Q45 Front Brakes 
Q45 brakes are a cheaper still upgrade to the brakes of your 240sx. They don't have the Nissan logo on the calipers. They are dual piston calipers that, compared to stock, provide about 25% more clamping force with a larger rotor and ~40% more pad surface area. They also have the pistons on the inside of the caliper so the wheel clearance is almost the same as with stock brakes, allowing the ability to continue running many different-sized wheels. Pads have many options as with all the other brake options we have here. The lines are the same fittings as stock so you can reuse your stock lines to save even more money.
You will need the following parts to make the Infiniti Q45 front brakes work on your 240sx: 2003 Sentra SE-R Rotors (Not Spec-V, those won't fit) mean you won't have to do a 5-lug swap. You will, however, need the stock SE "Teardrop" rims.
You will need a set of calipers from a 90-96 Infiniti Q45. These calipers are larger than the stock 240sx calipers. They use two 42.8 mm pistons instead of one 54mm piston to increase clamping force. These calipers will bolt onto the stock location as well as use the stock banjo brake lines.
There are many different rotor designs to choose from, but make sure you get the rotors to match your calipers. You can get slotted, cross-drilled or both on the same rotor. These features help your brake pad stay in contact with the rotor by providing a place to contain debri. Another point is that when some pads rub against the rotor, a gas is released, and this layer of gas between the pad and rotor reduces the brake's effectiveness. A slotted or cross-drilled rotor provides a pocket into which the gas can be compressed, leaving more of the pad material in contact with the rotor. It is pointed out above that perhaps modern pad compounds do not release this gas. Regardless, these rotors will wear out brake pads quicker than blanks. The Q45 came with 5 lug wheels as well as 5 lug rotors. This is not a problem for S14 SEs because they all came with 5 lug stock, but for us S13 guys there are 2 options. One is to convert to 5 lug (which is explained elsewhere on this wiki), or you can have the rotors re-drilled for the 4x114.3 lug pattern. Any competent machine shop should be able to do this. The Q45 rotors are approximately the same diameter as the 300z rotors, however the width of the rotor is in between the two thicknesses available from the 300z. The rotors are 28mm thick.---NEW POST---4 lug Nissan Altima rotors are the same diameter as 300zx and Q45. They are not as thick but are centered between the caliper perfectly. I have been using this set up for a few months with some extra shims and it works great. This really save time and trouble because there is no need to redrill or convert to 5-lug. Also they are only like 30 bucks a piece at any Autozone. !!New Post!! Also Sentra SE-R Spec-V brembo rotors can be used
The brake pad options are the same as with stock and they come in a lot of different compounds from mild to wild. Once again make sure you are getting the correct pad for the caliper/rotor set up you have.
Conversion lines are not necessary for doing the conversion, but make sure your brake lines are in good condition for safety's sake. Steel-braided brake lines are superior because the walls don't flex as much under pressure (more pressure to act directly on the calipers), and they also provide increased durability. The stock 240sx fitting is a banjo-style end and the Q45 calipers use the same connection.
The installation of the Q45 brakes is simpler than it would sound. The hardest part is cutting away or removing the splash guard from the front wheel hub. This can be done with a set of tin snips or an angle grinder. Once the splash guard has been removed the Q45 rotors and calipers will go on the same way the stock ones came off. Tighten down and bleed the brake system.
One of the benefits of the Q45 brake upgrade over many of the other one available is that the calipers and rotors are significantly less expensive than the 300zx and 240sx rotors and calipers. Furthermore, because they use the banjo brake lines the swap is quicker and can be done without having to replace as many parts. The Q45 calipers do not use as large an amount of brake fluid as the 300zx calipers due to the smaller piston sizes. This maintains a pretty equal bias between front and rear of the car without replacing the master cylinder or the rear brakes.
Infiniti M30 Brake Upgrade 
The M30 brake upgrade that is also available for the 240sx. The M30 used a larger rotor and single piston floating caliper which will increase braking power. The M30 was also a 4 lug vehicle, which makes it an ideal upgrade for those looking to increase their braking power without having to replace the 4 lug hubs or re-drill the rotor.
The rear M30 brake use an integrated drum design for the parking brake.
Maxima / 180sx spec Brake Swap 
The owners of S14's ('95-'98), can upgrade their brakes using 1995 Nissan Maxima calipers, rotors and pads, and for those with 4 bolt use 1995 Nissan Altima rotors with a 3mm spacer between the caliper and the spindle.
For the owners of S13s ('89-'94) You can upgrade your stock front brakes to JDM 180sx spec using USDM parts. This upgrades main benefit is the additional mass to the rotor for heat dissipation. The caliper pistons are not so large as to impact braking bias more than a trivial amount. The following will be needed for this swap:
('93-'97) 1st generation Nissan Altima rotors. These are 280x22mm and have a 4x114 bolt pattern.
('89-'99) 3rd and 4th generation Nissan Maxima brake calipers
('89-'99) 3rd and 4th generation Nissan Maxima brake caliper mounting brackets
('89-'99) 3rd and 4th generation Nissan Maxima brake caliper mounting bracket hardware kit
('89-'99) 3rd and 4th generation Nissan Maxima brake pads
These parts all directly bolt onto the s13 with no major modifications needed. This swap retains near stock
Before and after pictures of swap done on '90 240sx without abs:
Concerns worth noting:
-The brake swap will not fit anything smaller than a 15" alloy wheel. This will not clear a stamped steel wheel and drags on the caliper parallel surface.
- The stock rotor dust shield no longer clears the larger brake rotor. Modifications or removal to this are necessary for fitment. 2" deep slices with shears spaced 1.5" apart should be sufficient to allow the outside edge to be bent flat.
-The pad hangs over the edge from this setup by approximately 5mm. Although it is visually striking, it does not negatively impact braking performance or cause any reliability issues.
Master Cylinder Upgrade 
This only really applies to the Z32 brakes set up.
The stock master cylinder on the 240sx manual transmission is a 7/8" piston. That is fine for stock brakes, but you are now pushing between 10 and 12 pistons. Stock is just 4, so you can imagine that you will need a bigger master cylinder to help push more fluid and get the brake feel and bias closer to where you want it. There are many options of master cylinder sizes to go to. Many people have run all of these on different brake set ups, so its up to preference on which one you prefer. I have had a 7/8 (stock) 15/16 and a 17/16 and I think the 15/16 is perfect (stock brakes rear Z32 front). The 17/16 was much too stiff and hard to modulate.
Master Cylinder Sizing 
15/16 MC 
This came off of either a Z31 300ZX or an S12 200SX. This is the best set up if you plan on running Z32 front brakes with stock rear brakes. The bias is close to stock and the feel is perfect.
1" MC 
This came off of Z32 300ZXs made after 2/91. It is bigger than a 15/16", so this is better for a full brake conversion (front and rear Z32).
17/16 MC 
This is off of Z32 300ZXs made up to 2/91, and it is the biggest master cylinder you can get. It will give you an even firmer pedal feel.
On a S13 240sx with ABS these should all be direct bolt on, as the ABS models only have 2 lines running to the master cylinder. For non ABS you have to take out the middle screw (5 sided hex key) and put in a flare fitting to match your brake hard line. This can be attained from your stock master cylinder by cutting it out. As soon as you get this part out lightly tap it into the master cylinder. It is impossible to get it all the way in, so just get it to sit upright and use the brake line to make it square in the master cylinder. For S13 the lines are all in the right place, but for S14 you are going to need to bend the lines around to meet up with the master cylinder. Be careful not to kink them when you are doing this. Unbolt the old master cylinder from the brake lines and the brake booster and reinstall the new one. Done and done.
Aftermarket Big Brake Kits 
There are many aftermarket brake kits out on the market for the 240sx. These kits are usually very big (13"+ rotors) and they require the use of 17" rims. Also they usually come with 2 piece rotors, that is where the hat (the part that the wheel sandwiches between itself and the hub) and the rotor are 2 different pieces like Arizona z cars.