ATTENTION! Z31/Altima Rotor Rear Brake Owners!

[LoserCard]

Alright, for those who don't know one of the less common upgrades for rear 240SX brakes is the Z31 (84-87) Caliper Bracket and 2002-2011 Altima Rear Brake Rotor. However, there seems to be a common issue when doing this swap of a 2-5mm brake pad overhang on SOME swaps. What I am trying to do is isolate this issue by figuring out who has done this swap and what years they received their parts from.

So for anyone who has done this swap please chime in and submit your info in this form.

S13 or S14?
What year Z31 Bracket?
What year Altima Rotor?
Experiencing the pad gap?
Clearances between bracket and rotor? (Inner/Outer/Top)

I'll start with mine:
S13
86 Z31 Bracket
2003 Altima Rotor
2-4mm pad overhang
Clearances: Unknown (I took it off my car already, but I remember it being closer to the hub and maybe a 4-6mm gap on top)

I dug up some more info regarding the calipers and rotors, it is possible that there may be slight changes in these:
84-85 NA Z31 4 Lug Non Vented Rotor
84-85 Turbo Z31 5 Lug Non Vented Rotor
86 NA/Turbo Z31 5 Lug Non Vented Rotor
87-89 NA/Turbo Z31 5 Lug Vented Rotor

[float_6969]

I just bought a set of 86 rear caliper brackets, so I'll be able to tell you within the next week how they fit. I've also suspected that not all Z31 rear caliper brackets are the same. I'm wondering if the the issue is with the vented rotor vs. the non-vented. I'd be willing to bet that it's not only thicker, but also bigger in diameter, which would move the pad up too high, causing the overhang. Maybe we can come up with rear brake rotor diameters for the various years? The spindles were all the same, so a change in rotor diameter would be dealt with in the caliper bracket.

[Razi]

I don't know the year of my Z31 bracket, but it was N/A.
And my rotor is a non-vented one from a 2002-2006 Gen Altima.

[float_6969]

Any pad overhang? How did the rotor center in the bracket? Any interference with the antisway bar?

[LoserCard]

Hey guys, another quick update. I scanned through all the articles relating to the specific bracket and I have a hunch that it is the 87-89 caliper brackets. Let me explain why...

Here are the rotor dimensions from Centric's info: (Diameter x Thickness x Hat Depth)
84-85 NA Z31 4 Lug Non Vented Rotor (290mm x 10mm x 47mm)
84-85 Turbo Z31 5 Lug Non Vented Rotor (290mm x 10mm x 47mm)
86 NA/Turbo Z31 5 Lug Non Vented Rotor (290mm x 10mm x 47mm)
87-89 NA/Turbo Z31 5 Lug Vented Rotor (282mm x 18mm x 57.5mm)

The reason I think it is the 87-89 brackets is because that extra 4mm of pad gap I am seeing is the 8mm difference between the 84-86 and 87-89. The 87-89 bracket also sits further towards inwards due to the higher hat depth, which is why I most likely had about 1-2mm of gap between the inside of the bracket and about 7mm on the outside with my 84-86 brackets. Another thing that practically CONFIRMS it is the fact that my bracket run out where the rotor sits in between is only 15mm. If you look at ALL the pictures of the Z31/Altima Rotor conversions that DON'T have pad overlap, the bracket run out is ATLEAST 20mm since the rotor is 10mm and it looks like it could fit two in there. I am going to my local junkyard to pick up a pair of these 87-89 brackets to confirm this tomorrow. I will let you guys know.

BTW, Float_6969 sorry if you wasted your money on brackets. I saw your WTB post and was gonna warn you, but you had already bought them. I have had two sets of 86 Z31 brackets and they still have the overlap.

[LoserCard]

BTW, there is 3 of them at my local junkyard so I will pick up a few and test one set. If it works I will sell it to you if you want. Also as far as the sway bar interference, I think that will happen regardless of the correct bracket due to the increased hat depth, bracket, and rotor diameter.

[float_6969]

Thanks for the info. I didn't pay too much for them, so we'll see how it goes. I have an S14, so all of this may not even work the same for me.

[Razi]

Any pad overhang? How did the rotor center in the bracket? Any interference with the antisway bar?

Ooops, forgot to mention that.
I have zero overhang and the rotor centered nicely. No interference with the swaybar.

[LoserCard]

Can you measure the bracket gap where the rotor sits if you get a chance? The 84-86 Z31 bracket I have has a 15mm opening for the rotor. I think the 87-89 Z31 bracket should be around 20-25mm to accommodate the stock 18mm rotor.

[LoserCard]

Alright guys, I have acquired 4 brackets from 2 87 Z31's. I haven't installed them yet, but I noticed something interesting. I compared the 84-86 brackets to the 87-89 brackets and on the back side of the 87-89 brackets (facing inward) they have a rib that goes across the back. This is not on the 84-86's. So I scanned over all the forums with the Z31/Altima rotor conversion and from what I can tell, the brackets with no over hang are the 87-89 brackets.

Razi, I saw your DIY guide to this (diy-larger-rear-rotor-upgrade-t483332.html) and I am 100% certain you have the 87-89 caliper bracket.
The two reasons apparent in the second picture of your post:
1. The gap for the rotor is almost 2 times the size of stock. The 84-86 is basically the same size as stock.
2. There is a rib on the back of your bracket. The 84-86 do not have one, they are flat like stock.

So Razi, since you already have an awesome DIY, could you please update it to say that you need a 87-89 Z31 Rear Caliper Bracket.

[float_6969]

I just got my 84-86 brackets in today and I already have the Altima rotors. I wont have time to work on it tomorrow, but should be able to mess with it Thursday. The only thing I'm wondering about on the 87-89 bracket is that I thought that they didn't have the same diameter rotor as the 84-86, so will it sit on the Altima rotor correctly?

Also, if my setup doesn't work properly, I'd be interested in buying your extra set of 87-89 brackets.

[LeD ippen]

I have the 87-89 bracket right now and gonna switch back too stock soon. reason why is that if you use this bracket. you have to bend the tip of the shim and you must have these shims. when the bracket pad gets low it will just slide through the gap between the bracket and rotor without the shims. had it happen to me in winter and i had shims too but when i pulled ebrake a little to make lsd work better i lost a pad cause the shim bend a little and poad flew out. also before i did the swap my ebrake locked up perfect now it just doesnt even lock up.

[LeD ippen]

Rather have pad overhang then a missing one.

[LoserCard]

So after hours of research and test fitment. I have come to the conclusion that Z31/Altima Rotor conversions are NOT SAFE!

I repeat... NOT SAFE FOR USE!

Here why... First of all, the 87-89 bracket (which is the correct bracket with no over hang) is a bracket meant for a 18-20mm rotor. That being said, the cut out on the bracket for the rotor is approximately 22-25mm wide. The cut out on the stock bracket is approximately 14mm which is what it should be for a 7-8mm rotor. Therefore, when you use a bracket meant for a 20mm rotor with a 9mm rotor, when the brake pads get to around 40% there is a chance of pad blow out (meaning it will slip out of the bracket through the rotor cut out since it's too large). I believe people counter this with the stock caliper guides, however, once it gets down that low, the only thing that is holding the pad in place is a thin sheet of metal. Overall, this entire modification is only safe for the first 20-30% of the brake pads.

Also while researching, I was trying to come up with alternatives to counter this problem. The S13 caliper has 41.25mm of room, 27.4mm of that is occupied with brake pads (new). That leaves approximately 14mm of space for a rotor. I have come up with alternatives rotors in this size...

(Diameter x Disc Width x Height)
03-05 350Z: 291.8mm x 16mm x 62mm
97-01 Q45: 291.9mm x 16mm x 64.06mm

The ONLY way that these rotors might work is if they are shaved down to their minimum rotor thickness OR the pads were shaved 1mm each.

Other alternatives would be to use the 84-86 brackets and insert custom threaded sleeves in order to shorten them by 4mm (difference between 84-86 and 87-89 brackets is 4mm height and 14mm/25mm rotor cut out).

The last alternative is to figure out a way to rig up the 87-89 Z31 rear caliper e-brake cable up to an S chassis.

All this research is making my head hurt... I think I will just bite the bullet and do Z32 e-brake...

[LoserCard]

Wow I totally didn't read your post LeD ippen... Haha. But yeah, what he said! ^^^

[LoserCard]

Guessing I should have sold my rotor and brackets before unveiling this discovery...

Damn my good conscience...

[float_6969]

I haven't put mine one yet to see, it, but from what I understand, the problem with the 84-86 bracket is that it's basically too tall, right? So if you're using this bracket, you need a rotor that is 4mm bigger in diameter than the Altima rotor, right?

[LoserCard]

No it needs to be about 8mm bigger. A 300mm rotor. I haven't found and alternatives for a rotor of that size though.

[Razi]

Good work LoserCard!
I should go check up on my brakepads now, haha.

[LoserCard]

I am in the process of discovering if a rear 350Z vented rotor will work. Their measurements are 292x16x62. I'm going to have to shave the brake pad by at least 1mm on each pad. Luckily I have some used Duralast Gold pads. I will post my results and create a write up if it works. Later on I might try and retrofit the 87-89 300ZX caliper and make a custom bracket to work with our e-brake cables that way you don't have to shave the brake pads and I believe I saw a 292x22x64 rotor somewhere, but I can't remember.

[codyace]

This research is certainly interesting, as on my personal car there wasn't any issue with overhang; my roomates car however did have overhang. I've often wrote it down to a slight casting difference between where the caliper bolts to the bracket, and the bracket then to the hub itself. With that said, the ORIGINAL Z31 covnersion was from FreshAlloy, almost 6-7 years ago (stating non turbo brackets), one that I helped update and brought over to Zilvia, which was then transposed here.

TO consider this modification unsafe for all of them is very questionable (to me). Again, according to the above research, my car should have crashed and killed itself twice now, as my car has no overhang (which would be indicative of the 87-89 setup...although I have NO clue what year my brackets came from, nor did I know the rotor type as it was already stripped)....and with that all considered, I've burned though two sets of pads now...and this isn't from street use, but track time. Thi leads me to believe there is still a casting difference between the NON turbo ones.

With that said though, I will be measuring the difference first hand to see how close it gets. Again, I'm not saying that LoserCard's information is wrong...it could very well be correct (as Iv'e not researched it nearly as in depth as he has)...but my personal setup has been wore to the rivets, without any qualms, and that's with what I think looks like a NON TURBO bracket, but with no Overhang (using carbotech pads). I would NOT suggest using a TURBO bracket, as that does look very iffy at best...that I would agree is unsafe.

Again, not saying it's not plausible with the non turbo brackets...but I doubt there is any danger with them, as MANY MANY MANY users have done this with the non turbo brackets, with out issue (and have now for years). I will say that the Turbo ones DO look very questionable though.



And for the 184194x, pad overhang is just that, pad overhang. Heck I've had some cars have overhang on OE repalcement stuff to the shop. Sure you loose some friction material, but it's not going to cause crash and die situations. Maybe some noise at most. In the case of these rear bracket upgrades, a few MM in over hang is nothing to loose any sleep over, especially for the gain in swept area on the larger rotor.





For Reference:

I will say this though (and this is an old saved file of mine) that there is most certainly a difference in caliper PN and rotor PN between the 84-86 and 87-89.

Carquest Part Numbers:

1984 300zx
Caliper: (84-86_ 17-687
Pads (84-88) RD272
Rotor:
31136 (84-85) PREMIUM - EXC CANADIAN MODELS - w/TURBO
3152 (84-86) PREMIUM - VEHICLES BUILT FOR CANADIAN MARKET
3256 (84-85) PREMIUM - EXC CANADIAN MODELS - w/o TURBO


1986 300zx
Caliper (84-86) 17-687
Pads (84-88) RD272
Rotor:
31136 (86) PREMIUM - EXC CANADIAN MODELS
3152 (84-86) PREMIUM - VEHICLES BUILT FOR CANADIAN MARKET

1987 300zx
Caliper (87-89) 19-1221
Pads: (87-89) RD272
Rotor: (87-89) 31026


1989 300zx
Caliper (87-89) 19-1221
Pads: (87-89) RD272
Rotor: (87-89) 31026

[LoserCard]

Well you should be able to tell which bracket you have by measuring the rotor cut out on the bracket. The 84-86 bracket has a 15mm cut out and the 87-89 bracket has something like a 25mm cut out. The 84-86 bracket is also 4mm taller than the 87-89 bracket. Maybe you stumbled upon a bracket that actually works safely or brake pads/rotors that don't cause overhang. I will post up some pictures of all 3 brackets side by side to show the differences.

[codyace]

I had to re edit my post a few times here, due to going over old notes when I did this. My comment lies in the fact that the NON TURBO brackets (which these were based from in the initial F/A writeup) are perfectly safe, and that the turbo ones should most certainly be avoided.

[LoserCard]

Perhaps the 84-86 Z31 non-turbos had a larger rear knuckle to account for the smaller bracket because my research tells me that there are only 3 rear rotors for ALL types of Z31's: 290x10x47 (4 and 5 Lug) and 282x20x57.5 (5 Lug). I don't see why Nissan would change up their rear end but who knows... Could you possibly measure your bracket so we can get to the bottom of this? Measurements I need would be: Rotor cut out gap distance (mm), Distance between the bolts and the slide pins (mm), and your rotor diameter (mm). Also does yours have a rib on the back of the bracket?

[EliteGTR]

any update to this? codyace ever get a chance to take the measurements?

[LoserCard]

Sorry no updates on my part with the fitting of the 350z rear rotor. I have all the parts but my schedule got swamped. I still stand by my evidence of 84-86 brackets not working, and 87-89 being too big for the rotor.

[EliteGTR]

Just received a set of 87 non turbo brackets and the rotor opening is only 15mm (told they were an 87 but cant verify) does anyone have the bracket dimensions for the 84-86? i will test fit soon to see if there is any overhang and to make sure these arent 84-86.

[LoserCard]

15mm rotor opening is the 84-86 bracket. But let me double check the distance between the pins and the bolts on the ones I have.

[EliteGTR]

yea but i thought we didn't know the opening of the 87-89 non turbo and thats what these are suppose to be.

[LoserCard]

Well I have 4 sets of brackets, 2 84-86 (15mm brackets), and 2 87-89 (25mm brackets). So unless you have the missing link which Codyace claims to be a perfect fit, then you most likely were tricked into believing the ones you purchased were from a 87-89 but are actually 84-86. My research only tells me that there were only 3 types of rotors for Z31's: 4 lug 290x10mm, 5 lug 290x10mm, and 5 lug 282x18mm. If what Codyace is saying is true, there should be a 282x10mm rotor or a year when Z31's changed their rear knuckle to offset the caliper mounting points. So far, I haven't found any evidence of that though and he doesn't seem to want to respond about his brackets... Maybe his rear brake pads flew out and he is now incapacitated and is unable to measure his rear brackets. =P

Jk, I wouldn't wish that on anyone.