300zx brake upgrade questions....?

[pepesilvia]

looks like my front calipers are starting to seize a little, so im going to use that as an excuse to buy new front calipers. Silver mine motors offers 300zx brakes that im guessing are rebuilt (like new!) for about $500 for everything i need http://www.silverminemotors.com/240sx-f ... ke-kit.htm.... BUT i also need to upgrade the master cylinder as well, correct? or else it'd be a waste.... so i have a couple questions.... 1.) if i upgraded my master cylinder to this one inch cylinder http://www.silverminemotors.com/240sx-U ... linder.htm with my stock calipers would it make the braking better or worse? someone told me that there would be some kind of ratio imbalance and it would make my braking worse.....? 2.) why are there two places for reservoirs on the master cylinder?... confuses me.... any help would be appreciated! thanks dudes

[blkvrtswp]

You don't have to change the Master Cyl for Z32 caliper upgrade. I left it stock on 2 of my personal cars and countless customer cars with no issues at all. I say leave it for now, if you do not like the pedal feel then think about changing it.

[compactfean]

Yeah I did mine w /o switching master. I didn't like the feal of it so eventually switched to the z32 bmc.

[pepesilvia]

aight, but what if i switched the master cylinder BEFORE changing the calipers? hmmmm???

[compactfean]

Well considering my pedal went stiffer than a hard on in a whore house on viagra when I did the upgrade without switching master.... Maybe itll just be a soft pedal with out the break upgrade.

[Hijacker]

I've posted this before, but it's time to post it again.

Making the brakes work
After installing the Brembo Gran Turismo 300ZX front brake kit and Z32 300ZX rear brakes back in part 1, we pointed out that a bigger master cylinder would really be needed to get proper Brembo pedal feel. We also complained of premature rear-wheel lockup and somewhat average 130-foot stopping distances from 60 mph.

The diameter of the master cylinder determines both how much brake force you'll get for a given pedal effort, and how much pedal movement there will be. The stock 7/8-inch master cylinder has a piston area of 0.60 square inches, so 100 pounds of force shoving on the piston from the combined effort of your foot, the pedal lever ratio and the brake booster, will make 167 psi (100 lb/0.60 in2) of fluid pressure with which to squeeze the calipers. Moving to a 1-inch master cylinder gets you 0.79 square inches, which makes only 127 psi from the same 100 pounds of footwork.

Since we had complained that the brakes felt touchy and overboosted, this reduction in pressure would be exactly what we needed. We also complained that there was too much pedal movement. The bigger master cylinder helps here, too. A 7/8-inch cylinder moving 0.1 inches pumps .060 cubic inches of fluid to the brakes. A 1-inch cylinder would pump .079 cubic inches. That means it would take less pedal movement to move the brake pads the fraction of an inch from their resting position to the rotors.

Checking the Nissan parts books, the Z32 300ZX shares the 240SX's master cylinder design, but comes in 1-inch and even 1 1/16-inch sizes. Wanting a big change in pedal feel, we went for the bigger cylinder (part number 46010 30 p21) This would increase pedal effort by 65 percent. (The 0.99-square inch bore would make 101 psi at 100 pounds of pedal force, or need 165 pounds to make the same 167 psi the stock cylinder made at 100 pounds.) Since the bigger cylinder pumps 65 percent more fluid for the same stroke, it would also significantly reduce pedal slop.

When I had my Z32 fronts with S13 rears and S13 MBC, I routinely would lock up my front brakes way too easily. The S13's MBC is too overpressured for the Z brakes, and the proportioning bias is off. When I swapped my rears out for Z32 rears, I also swapped up to a 1" MBC. I went from having a sensitive, over pressured braking system to having great pedal feel. My braking distance was also reduced since my front wheels were less prone to lockup.

I always recommend upgrading the MBC when you do a big brake upgrade.

I don't think you should upgrade the MBC without doing the calipers, however.

[compactfean]

Idk about everyone else but being on my phone, surfing on here you can't find s***. All mods say ”ill post it one more time for you but search and you will find”.... Bs..... Sooo not true. Lol we need an app for that.

[dohmann777]

Agreed

[pepesilvia]

I've posted this before, but it's time to post it again.

Making the brakes work
After installing the Brembo Gran Turismo 300ZX front brake kit and Z32 300ZX rear brakes back in part 1, we pointed out that a bigger master cylinder would really be needed to get proper Brembo pedal feel. We also complained of premature rear-wheel lockup and somewhat average 130-foot stopping distances from 60 mph.

The diameter of the master cylinder determines both how much brake force you'll get for a given pedal effort, and how much pedal movement there will be. The stock 7/8-inch master cylinder has a piston area of 0.60 square inches, so 100 pounds of force shoving on the piston from the combined effort of your foot, the pedal lever ratio and the brake booster, will make 167 psi (100 lb/0.60 in2) of fluid pressure with which to squeeze the calipers. Moving to a 1-inch master cylinder gets you 0.79 square inches, which makes only 127 psi from the same 100 pounds of footwork.

Since we had complained that the brakes felt touchy and overboosted, this reduction in pressure would be exactly what we needed. We also complained that there was too much pedal movement. The bigger master cylinder helps here, too. A 7/8-inch cylinder moving 0.1 inches pumps .060 cubic inches of fluid to the brakes. A 1-inch cylinder would pump .079 cubic inches. That means it would take less pedal movement to move the brake pads the fraction of an inch from their resting position to the rotors.

Checking the Nissan parts books, the Z32 300ZX shares the 240SX's master cylinder design, but comes in 1-inch and even 1 1/16-inch sizes. Wanting a big change in pedal feel, we went for the bigger cylinder (part number 46010 30 p21) This would increase pedal effort by 65 percent. (The 0.99-square inch bore would make 101 psi at 100 pounds of pedal force, or need 165 pounds to make the same 167 psi the stock cylinder made at 100 pounds.) Since the bigger cylinder pumps 65 percent more fluid for the same stroke, it would also significantly reduce pedal slop.

When I had my Z32 fronts with S13 rears and S13 MBC, I routinely would lock up my front brakes way too easily. The S13's MBC is too overpressured for the Z brakes, and the proportioning bias is off. When I swapped my rears out for Z32 rears, I also swapped up to a 1" MBC. I went from having a sensitive, over pressured braking system to having great pedal feel. My braking distance was also reduced since my front wheels were less prone to lockup.

I always recommend upgrading the MBC when you do a big brake upgrade.

I don't think you should upgrade the MBC without doing the calipers, however.

major help, thanks

Idk about everyone else but being on my phone, surfing on here you can't find s***. All mods say ”ill post it one more time for you but search and you will find”.... Bs..... Sooo not true. Lol we need an app for that.

.... and hell yes

[Hijacker]

There's a lot of threads covering the topic, but search is manageable, even on smart phones, if you know how to limit and display results. I always have it spit back topics instead of posts. That's the big one, you can go from thumbing 300 pages to 10 pages really quick that way. There's a lot of posts about every subject and it's daunting to cycle through it all. I put in '300ZX brakes' and 'Z32 Brakes' and returned 25-30 pages of topics. That's a lot, but it was a general topic search. I'm sure if I narrowed it with 'master cylinder', or 'bmc', I could cut that number down. I surf NICO on my phone a lot, and I use the search function the exact same on my phone as my desktop with no issues.

Now, I don't expect everyone to pore over every old thread of NICO. If that were the case, we'd have next to zero posts/day as most topics have been covered ad naseum. Maybe I should have chosen my words more carefully as I didn't mean to come across as "stupid noobs, search!" when I said it had been a while since I had posted Coleman's words. The last time I could find that I had quoted that article was in '09, so it's been a while, and it was buried deep in a thread. The only way I found it was to search for my posts specifically about Z brakes. I would never expect any of the members to be that diligent with searching.

Now, I will say that if a member shows up with a tired thread topic such as 'How do I install Z32 brakes?', then I might wave the search flag. This was a more legitimate question about his situation and what he should do. That's why I was trying to go out of my way and not sound like the search police. Obviously I failed at that so I apologize.

But I don't want to get too far off topic from the OP. If anyone wants to discuss the state of searching, please feel free to IM me, or we can open up the discussion in Gen Chat to get some good feedback between the staff and community.

[asoomal]

I've switched my master to the 1" Z32 ones because I had one laying around when my stock one died. With the stock calipers and the ABS double diapghram booster, the pedal is verrryy firm and not much happens when you press on the pedal, less pressure, but more volume.

[pepesilvia]

There's a lot of threads covering the topic, but search is manageable, even on smart phones, if you know how to limit and display results. I always have it spit back topics instead of posts. That's the big one, you can go from thumbing 300 pages to 10 pages really quick that way. There's a lot of posts about every subject and it's daunting to cycle through it all. I put in '300ZX brakes' and 'Z32 Brakes' and returned 25-30 pages of topics. That's a lot, but it was a general topic search. I'm sure if I narrowed it with 'master cylinder', or 'bmc', I could cut that number down. I surf NICO on my phone a lot, and I use the search function the exact same on my phone as my desktop with no issues.

Now, I don't expect everyone to pore over every old thread of NICO. If that were the case, we'd have next to zero posts/day as most topics have been covered ad naseum. Maybe I should have chosen my words more carefully as I didn't mean to come across as "stupid noobs, search!" when I said it had been a while since I had posted Coleman's words. The last time I could find that I had quoted that article was in '09, so it's been a while, and it was buried deep in a thread. The only way I found it was to search for my posts specifically about Z brakes. I would never expect any of the members to be that diligent with searching.

Now, I will say that if a member shows up with a tired thread topic such as 'How do I install Z32 brakes?', then I might wave the search flag. This was a more legitimate question about his situation and what he should do. That's why I was trying to go out of my way and not sound like the search police. Obviously I failed at that so I apologize.

But I don't want to get too far off topic from the OP. If anyone wants to discuss the state of searching, please feel free to IM me, or we can open up the discussion in Gen Chat to get some good feedback between the staff and community.

yeah, i dont think its so important that we need to open up a discussion about it, but sometimes it can be hard to find specifics like the question i asked. but the search tool is EXTREMELY useful the way it is. answers MOST of my questions....

I've switched my master to the 1" Z32 ones because I had one laying around when my stock one died. With the stock calipers and the ABS double diapghram booster, the pedal is verrryy firm and not much happens when you press on the pedal, less pressure, but more volume.

.... thats what i was looking for. thanks CASE CLOSED I THINK, aye?