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View Full Version : 300zx brake swap MC question for those who have the swap.


240m3srt
07-28-2005, 09:27 PM
Hey guys, i have the 300zx front brake swap with ss lines and Hawk HPS pads and its been a great mod thus far. Today i decided to go ahead and do the 1 1/16 300ZX MC. The pedal is much firmer and at first i thought wow this feels great...till i drove it. It requires about 3 times the effort to push the pedal...meaning its harder to brake :wtf: If i push "really" hard i can lock em up but i definitely like the way it was before i dont think i can drive it like this it wears out my calf...lol. And if i were at a track day....FORGET IT.

The only thing i can think of is that in the next few days ill be doing the 300zx rears, maybe that will make it better, after all it will officially have the 300zx full brake setup at that point, because to my best knowledge there is no difference in the proportioning valve. If that doesnt help the pedal im going back to the stock MC.

Has anyone had this experience or have any helpful input?

infinitexsound
07-28-2005, 09:36 PM
well when u do the full z32 and run stock MC its gonna be a hard ass pedal...... but when u do decide to do the full z32 pedal feel will be alot diff. then what ur feeling now...........

in ex. i did the full z32 on a s14 chassis and running a z31 15/16 MC and pedal feel is alot better then when i had it with stock.... u should research because theres so many threads in zilvia about splitting points and different MC's ...

240m3srt
07-28-2005, 09:46 PM
Im kinda new here, and it seems like some forums have great search archives and others suck. I will search and see what i can find from others experiences.

Sil-Abc
07-29-2005, 06:08 AM
http://importnut.net/300zxbrakeswap.htm#MC

just get an automatic brake booster. should make the pedal feel a bit more "comfortable"

240m3srt
07-29-2005, 09:08 AM
http://importnut.net/300zxbrakeswap.htm#MC

just get an automatic brake booster. should make the pedal feel a bit more "comfortable"

Not a bad idea but i could not tell from the article if that meant an automatic booster from a 240 or a 300? Any input?

BTW i emailed that import nut guy he gave me the recomendation of possible going to the auto 240 15/16 MC. I guess im trying to make sure i dont buy 50 different combos to get it right.

mbmbmb23
07-29-2005, 09:35 AM
Sounds like they need bled again.

240m3srt
07-29-2005, 10:07 AM
Sounds like they need bled again.

Interesting thought and maybe your right but usually when theres air in the lines my experience has been you can "feel" it during the firts part of initial pedal stroke then the brakes "come on". Here it just feels solid from the get-go.

Something odd i noticed is that for an out of the box MC it didnt seem to require much bleeding at all. Almost too easy. I bench bled the MC. I gravity bled the front lines(left them open for all fluid to drain). When the new MC was installed within the first few pedal strokes fluid poured out(and a lot of it) with no signs of air. So i dont know its always worth another shot.

I guess ill see how it feels with the 300zx rears. I know that cars weight and weight distribution is different that a 300zx but it should be pretty close, and i cant imagine a 300zx brakes feeling this way, though ive never drove one. Seriously given the demographic of those who used to buy them they would get returned the day they left the lot if they even felt close to this. A car stopped abruptly in front of me today and it required all i had to slow the car....it takes a lot of pedal force to lock them up when it used to be cake.

HyperTek
07-29-2005, 11:12 AM
just get a 91 tt brake booster.. thats what i have in now.. tho i had a none-turbo booster in it before (dont know what year) and i think it felt better but it was leaking so i put a 91 tt in it.

r32gtr
07-29-2005, 11:25 AM
I'm going through the same thing, at first my 300 front and the 300 mc was fine, but then my booster went, cuz the old mc was leaking into it, and now that i have the booster with a stock replacement from advanced the pedal barely moves it stops but barely moves, it killed my autox season till i can figure it all out. some of friends and even my shop agree it is probaly because im still running the stock rear brakes.

240m3srt
07-29-2005, 01:33 PM
Sounds like my best order of steps will be to first do the rear swap. If that doesnt fix it ill do the booster. If that doesnt work its time for a new MC.

The 300zx MC is a direct bolt onto 240sx...right?

Sil-Abc
07-29-2005, 01:54 PM
yes. go to any junkyard and grab the booster. any 240sx booster will fit. right now im running a 17/16 300zx booster with a s14 auto booster. havent tried it yet but ill let u kno good luck doing the rear setup. post pics and let me kno what u did to do it. I wanted to do my rear but its goin to be hard splicing those ebrake lines

240m3srt
07-29-2005, 03:46 PM
Sorry what i typed in my last post made no sense. I already had the 240sx master cylinder and i switched to the 1 1/16 300zx MC. My question should have been will the Z32 300ZX Brake booster swap right on with no mods necessary?

BTW i think i got you confused you said "right now im running a 17/16 300zx booster with a s14 auto booster", but i knew what you meant.

I will let you know how the rears go i plan on kicking its ass this weekend if i can get all my parts in a row.

240m3srt
07-31-2005, 02:30 PM
Well the nissan yard sold the entire rear swap before i could get there after i specifically had them pull it for me. They said they thought the other dude was me so they sold it:nono: Hopefully they will be getting another one in soon.

I tried searching and am a still uncertain about if the 300zx BRAKE BOOSTER will bolt right up to my 97 240? And is there a differecnce in the auto or manual version or will either work?

240m3srt
08-01-2005, 11:29 PM
I doubt anyone is following this thread or cares but i figured id update for if anyone ever searches. This is probably old news but its new to me, as i just found out the hard way. :-/

I currently have the 300zx front brakes and the 300zx 1 1/16MC. It felt firm but VERY hard to push. I just upgraded to a 300zx brake booster and its a millon times better. Its back similar to stock ease of brake pedal but a little stiffer. Makes me wonder if the booster and MC was even worth doing, but i feel confident that when i do the rears it will all come together and work as a complete package. From my best understanding the 300zx auto and manual brake booster are the same, as there was only one part available. Please note the 300ZX booster is a TIGHT fit. If you try to install it as is on an s14 you will probably not be able to do it and you will scratch the inside of your driver shock tower to hell. The 4 studs that mount the booster to the firewall must be cut roughly 3/8(measure your stocker and you will see the difference. Without doing this it will be hard/impossible to install the unit. Also, you must be sure to screw the nut and forked piece down to the base of the stud on the brake booster shaft facing the interior cabin side. Again, if you put the stocker side by side you will see why. Lastly, you must space the MC/brake booster combo forward. This is very important as to not preload the MC, if you do not do this you will find out quick that your brakes are engaged even when the pedal is not depressed. I used a washer probably about 3-4mm wide in between the MC and brake booster and voila!! I dont like how it looks however and i will probably go back tomorrow and put the washers between the brake booster and the firewall instead. same thing. Keep in mind all this was done with the MC still attached to the brake lines i just had to move it forward and bend the lines a little.

Next step rear brakes.

importnut
11-11-2005, 02:07 PM
Looks like this is old news, but your concern about preloading the MC. The "pin" that attaches to the actual brake pedal is adjustable. You need to losten the top nut, then use a pair of plyers on the ribbed part of the "pin" to adjust how far in or out it sits. You should not shim the booster away from the firewall. I would go as far as to say it's a bad idea. I had adjusted mine so that it engages very quickly. I only have a fraction of an inch worth of play before the pads start to bite.

The issue about how hard the pedal is when you do the MC and calipers. It is harder, but with good pads, it isn't bad. When I had Hawk HPS's on my 240, the brakes sucked. Pedal feel was awesome, but as 240m3srt commented, it takes a huge amount of pressure to make the car actually stop.

With Porterfield R4S pads, the pedal seems lighter. Since the pads are awesome, it doesn't take much effort to stop. When you do nail the brakes, it stops hard! If I want to lock the tires up, that's a piece of cake too.

As far as using the 300zx booster, which now I'm glad someone has done it and documented it, it will match the brakes to the MC and to the booster. Granted, the pedal itself might be different, so it won't be 100% 300zx. You mentioned concern as to doing the MC and booster being pointless if it feels the same....it has to do with the volume of fluid that you push.

To me, good brakes aren't just about slamming on them and seeing how a car stops. It's the feel. How does it feel given specific pedal pressure. How much does the pedal move, etc. In my 240, the pedal doesn't seem to move once the pads engage the rotors. It's not how far the moves, but how much pressure I put on the pedal that makes it feel so great.

-Alex S.

killjoy
11-11-2005, 02:22 PM
I have z32 front and rears with a 1" bmc. I don't really like the feel. The brakes don't have much play which is fine and they do stop okay but they lock up to easy. I can lock them up at 50mph no problem with not much force. I think if I go to the 17/16 it might be worse. I almost want to go back to 15/16 and try it and I bet I would like it better. So far at least I like the z32 front and 15/16 bmc and stock rears better than my current setup of z32 all around and 1" bmc.

importnut
11-11-2005, 03:29 PM
That's what my setup seemed like before I went to porterfield pads.

Tires may be the culprit too. I'm curious. I'm really happy with mine. I can stop on a dime and it feels great. I have to pound the brakes hard to get them to lock up. I'm not even running that fantastic a tire.

I can't see these brakes being so powerful that the 240 is too light for them. It doesn't make sense.....anyone want to continue on with this thought?

-Alex S.

middy
11-11-2005, 06:54 PM
I can't see these brakes being so powerful that the 240 is too light for them. It doesn't make sense.....anyone want to continue on with this thought?

-Alex S.

As a previous owner of a 300ZXTT, I can say that its brakes are definitely inadequate for its size. The Z is too heavy for them. It takes too long to get stopped, and they often fade on the track.

Take ~700-800 lbs off, and I think you should have great brakes. But I doubt they would be too powerful. I've driven a Silvia with enormous StopTech front brakes and Z32 rears, and it feels great and stops on a dime, yet still has too much rear brake bias. You have to be careful about locking up the rears and flatspotting the tires.

So yeah...a full set of Z32 brakes isn't gonna be too powerful for 240s.

importnut
11-13-2005, 01:48 PM
That's what I thought. The Z doesn't way that much more.

I was thinking about a few Civic applications where upgrading the MC and front brakes usually yields in overly easy lockup. In those cases, it's been really pitiful rear drum brakes and incorrect proportioning.

I think that there is another angle here that I didn't really delve into. As I mentioned the pedal movement is reduced substantially. When you are used to a pedal that gives you a wide range between initial bite, to lockup, that you expect the brakes to act the same when the pedal movement is reduced. So, let's say for the sake of numbers, the pedal moves 3" before the upgrade, and only 1" afterwards. Your foot/brain expects it to act a certain way, and then you end up with a lot of tire smoke. I think that is where most people are to be faulted. You have to get used to the new setup.

The second part is to not be cheap with pads. I had Hawk HPS pads and they sucked furiously. With a good set of pads, you can modulate brake output very effectively.

I wouldn't trade my setup for anything at this point.

-Alex S.

Muzzy
11-14-2005, 10:58 AM
sooo.....you are better off with stocK MC because of pedal pressure needed??

Ritz S14
11-14-2005, 11:52 AM
Don't know about you guys. But I LOVE the pedal feel on my stock BMC and z32 26mmFronts and z32 rears. The pedal is low, but it feels great. Takes very little effort to stop the car.

DJPimpFlex
11-14-2005, 08:36 PM
I have front z32 26mm with axis ultimate pads all arround and a 15/16 BMC. There absolutely perfect. I dont believe you need anything better than the stock brake booster, because you can adjust that pin as stated above.

importnut
11-16-2005, 08:45 AM
sooo.....you are better off with stocK MC because of pedal pressure needed??

I believe it comes down to personal preference. In either case, the brakes work. Isn't that the most important part? Whether you adjust the pin or not, it still takes more movement to engage the brakes using the stock MC. I do not like that. I like the fact that the pedal almost stops as soon as the pads engage the rotor, and from that point, it's about how much pressure you put on it, not the movement of the pedal.

I believe that the problems people are experiences with the stiff pedal can be summed up in a few thoughts. 1) hit the gym ;) 2) nearly every other car out there has typical brakes where you have greater pedal movement that makes it easier to manipulate the brakes. Switching to the far more solid setup with the Z32 MC definitely takes a bit to get used to and also requires good brake pads. Hawk HPS pads are terrible and yield lousy brakes. A good pad like the Porterfield R4S makes the setup feel better than anything I've experienced.

Ultimately, swapping the brakes, and associated parts, is to help you stop in shorter distances, and more importantly, over and over again. Stock brakes can lock up the tires, or take care of you for one good panic stop, but after that, forget it.

docrice
11-16-2005, 09:42 AM
Don't know about you guys. But I LOVE the pedal feel on my stock BMC and z32 26mmFronts and z32 rears. The pedal is low, but it feels great. Takes very little effort to stop the car.

Dude I'm with him... the firmer feel is much better (I'm running front and rear z32 calipers, 1" MC, and braided lines, and that bitch is firm) . Why would you actually want softer brakes and a longer pedal throw? Softer brakes seem less reassuring and harder to feel out. The only thing i've noticed with this setup is that it can be a bit more difficult to sense when the fronts are going to lock on me, but i think that is in part due to not bedding the pads correctly (I rushed it since i wanted the car back on the road and i only planned to run it a few months on the OEM pads...they held up a LOT better than I had expected.) We'll see how it feels once I get the Hawk pads on there for spring. Reguardless, the pedal feel is personal preference, I just can't see why you'd want it to feel weaker...but whatever works for ya.

CHARLIE2020
12-22-2005, 12:00 AM
Here my personal experience with Q45 and Z32 brakes all around on my S13 coupe:

Q45 brakes all around with stock 7/8" BMC = TOTALLY FUCKING AWESOME

Z32 brakes all around with 1 1/16" BMC = Firm pedal, very short lived travel and very hard to lock them up

Z32 brakes all around with stock 7/8" BMC = Pretty bad ass after you adjust some slop out of the pedal via the locking nut and pushrod adjustment, this set-up seems to hault you down alot quicker than that of the 1 1/16" BMC

All in all right now I feel like I down graded buy selling my Q45 brakes and buying Z32 brakes :(.

I have a Z32 N/A NABCO 1" BMC that I will be trying tommorrow, if i had to guess I would say it takes alot more pedal effort to stop with fixed calipers vs sliding calipers and therefore the extra asist from a smaller BMC is usfull in this situation.