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gvincent

Toyota S12+8 myths but need real facts

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In my search for this caliper I found a lot of statements that say this is a solid rotor only caliper. This is simply not true! there is a wide version with the same marking as Zcarnut pointed out in post #6 of this thread:

http://forums.hybridz.org/showthread.php?t=104735

He posted pictures of the 2 different calipers, the 1979-85 4x4 was a solid one and the 1986-88 4x4 calipers are also marked "S12+8" but were designed to fit the wider, vented rotor.

Also Waynekarnes posted a really good post on the different set-ups in post #14 of this thread:

http://forums.hybridz.org/showthread.php?t=94050&highlight=s12-8

 

Now the Brake Upgrade FAQ, http://forums.hybridz.org/showthread.php?t=103767

does not mention these calipers at all, so I searched somemore and that was when I found all the Myths about them being only solid.

 

Well I tried to find a "package" that could be verified and WayneKarnes came the closest in his "Port B" section which is copied below:

 

Port B: Small Four Piston Front Brakes with Solid or Vented Rotors 4 X 4 1/2†lugs. Major parts include:

1979-81 Nissan 280ZX 15/16†master brake cylinder

1970-73 Nissan Z hubs 4 X 4 1/2†lug pattern

1970-78 Nissan Z rotors 4 X 4 1/16†bolt pattern

1979-85 Toyota 4X4 4 cylinder pickup with solid rotor, front calipers marked ‘S12+8’

OR

1984-85 Nissan 300ZX front rotors 4 X 4 1/16†bolt pattern

1986-88 Toyota 4X4 4 cylinder pickup with vented rotor, front calipers marked ‘S12+8’

Eight bolts grade 10.9, 8 X 1.25 thread diameter and pitch 40 mm long with lock washers

Two metal spacer as listed below;

O.D. 155 mm

I.D. 81 mm

Thickness 17 mm

Four 10.5 mm holes spaced 4 1/16†equidistance

The front dust shield must be trimmed to accommodate the larger caliper, bend your old brake lines gently to fit, make sure they don’t touch anything or they will rub a hole in the brake lines.

 

Now what I am confused about is the spacer thickness that is needed, it seems with further searching that many different sizes were given, .500 for 240Z and .375 and .315, 8MM for 280Z's now granted these were listed for S12W calipers which is different from the S12+8 but the 17MM thickness is given (0.66929134) in Wayne's post for Both "Port A" and "Port B" applications????

 

SO IS IT FACT that for a 76 280Z I need the following:

(2) 1986-88 Toyota 4X4 4 cylinder pickup with vented rotor, front calipers marked ‘S12+8’

(2) 1984-85 Nissan 300ZX front rotors 4 X 4 1/16†bolt pattern

(2) metal hub spacers:

O.D. 155 mm

I.D. 81 mm

Thickness 8 mm????

Eight bolts grade 10.9, 8 X 1.25 thread diameter and pitch 40 mm long with lock washers

 

Now I am also curious about the S13W caliper but could only find 5 threads that it is metioned in. Comments were large piston area and uses large pads but they are heavy. so this is not an attractive choice I gather.

 

So for decent piston and pad size and weight the S12+8 caliper is preferred over the S12W from what I can gather from my searches and not having to mess with porpotion valves etc which seems to be the case with the larger S12W

Now if I can verify what size spacer and where to get them cheaply I will be set to go and Stop.

Thanks,

Greg

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"1970-73 Nissan Z hubs 4 X 4 1/2” lug pattern

1970-78 Nissan Z rotors 4 X 4 1/16” bolt pattern"

That makes no sense...how can the rotor have a smaller bolt pattern than the lug pattern? If I recall correctly they have the same bolt pattern so that the rotor slides over the lug bolts.

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"1970-73 Nissan Z hubs 4 X 4 1/2†lug pattern

1970-78 Nissan Z rotors 4 X 4 1/16†bolt pattern"

That makes no sense...how can the rotor have a smaller bolt pattern than the lug pattern? If I recall correctly they have the same bolt pattern so that the rotor slides over the lug bolts.

 

rotor bolts on the back of the hub.

 

I have a pair of the S12+8 calipers right now, and they are the later wide style. It would be interesting to do a side by side comparo of all three. Modern motorsports carries the spacers, and braided lines in thier 'typical 4x4 brake package' which is where I will be getting mine from.

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SO IS IT FACT that for a 76 280Z I need the following:

(2) 1986-88 Toyota 4X4 4 cylinder pickup with vented rotor, front calipers marked ‘S12+8’

(2) 1984-85 Nissan 300ZX front rotors 4 X 4 1/16†bolt pattern

(2) metal hub spacers:

O.D. 155 mm

I.D. 81 mm

Thickness 8 mm????

Eight bolts grade 10.9, 8 X 1.25 thread diameter and pitch 40 mm long with lock washers

 

Now I am also curious about the S13W caliper but could only find 5 threads that it is metioned in. Comments were large piston area and uses large pads but they are heavy. so this is not an attractive choice I gather.

 

So for decent piston and pad size and weight the S12+8 caliper is preferred over the S12W from what I can gather from my searches and not having to mess with porpotion valves etc which seems to be the case with the larger S12W

Now if I can verify what size spacer and where to get them cheaply I will be set to go and Stop.

Thanks,

Greg

 

I'm using the s12 + 8 vented calipers so

 

(2) 1986-88 Toyota 4X4 4 cylinder pickup with vented rotor, front calipers marked ‘S12+8’

(2) 1984-85 Nissan 300ZX front rotors 4 X 4 1/16†bolt pattern

 

are true.

 

You should mock up your new setup with washers and measure your hub and new rotors to determine your spacer dimensions. Some people need a wider spacer for better wheel/caliper clearance. I'm using a 280z hub on 240z axels. My spacer width is .355 " just like danman's, but wheel clearance with one set of rims is almost paper thin. Note that when the braking system heats up, the wheel and caliper can start to rub even though it doesn't when cold if clearances are too tight. Also note that I have never mounted new rotors where the clearances would be tighter. If your going to make spacers without mocking up first, I would error to the wide side. You can use thin washers for mounting the calipers, if there is rub with the rotor.

 

I swapped out the s12 + 8 vented calipers with my friend's s12w's for a day without any rubbing issues so the offset between the two calipers is pretty close. I swapped calipers because the track pads I ordered ended up being for the s12w instead of the s12 + 8. I searched but could not find someone who has off the shelf track day pads for the s12 + 8's. I found a pretty close fit using pads for a second gen rx7 with the sport suspension(different caliper from the regular suspension). It requires a little modification to fit.

 

The s13w's require more mods from what I've read here. The s12w's have enough leverage for me when using the 15/16th master cylinder. For my s12 + 8 vented's, I prefer the extra leverage of the 7/8th mc even though pedal travel is a little longer.

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Thanks GrommitZ,

So you prefer the S12W rather than the S12+8?

No performance pads for the S12+8?

Maybe I should re-consider the S12W's?

Can I use my 280Z hubs and axles or do I need to locate some 70-73 240Z hubs? Now I am confused again... (easy to do)

But I still need the .355 or the .315 spacers with the 280Z or 240Z hubs??

This should be simple right??, why don't I get it!

Thanks,

Greg

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Thanks GrommitZ,

So you prefer the S12W rather than the S12+8?

No performance pads for the S12+8?

Maybe I should re-consider the S12W's?

Can I use my 280Z hubs and axles or do I need to locate some 70-73 240Z hubs? Now I am confused again... (easy to do)

But I still need the .355 or the .315 spacers with the 280Z or 240Z hubs??

This should be simple right??, why don't I get it!

Thanks,

Greg

 

 

Hi Greg,

 

I didn't give a preference because I haven't optimized either setup yet to make the comparison fair. If you track your Z, I recommend trackday pads. OEM pads will fade and shudder. Yes, I don't know of off the shelf trackday pads for the s12 + 8 vented. The rx7 pads I mentioned above will need a little modification. I currently have only the outboard pads on. The inboard one's will need more grinding before I use them. I'm using the rx7 Hawk HP+ for the s12 + 8 vented and tried the Satisfied gs5 pads with the s12w's, though the gs5's are no longer available for the s12w's through tirerack. Both pads work much better than oem. Some complain of excess noise and rotor wear with the HP+. I notice only minor noise, but I'm only using the outboard pads right now. The rotors do wear, but have worn smoothly.

 

As for the spacer, I'm using the 280Z hub on my 240Z strut. I prefer the 280Z hub because it uses a thinner spacer than the 240Z hub. I'm not sure what differences there are between the 240Z and 280Z struts. I'm using a .355 " spacer, but I still strongly recommend that you mock up your setup with washers first and measure them. My caliper barely clears one of my rims. A wider spacer would be safer because you can always turn it down if you need to instead of starting over.

 

I'm happy with my S12 + 8's, but I liked the s12w's too. Again, I've been making so many changes between track days that I can't come to a firm conclusion between the two. Based on pad availability, the s12w's might be better. Based on balance with the stock rear drums, the s12 + 8's might be better. I had fewer lockups with the s12 + 8's, but that could be because of my pads, tire pressures, track conditions, experience with the setup...etc.

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It’s great that Toyota is moving into EV with more enthusiasm. They are one of the big guns, so whatever they do will push all the other companies. It hasn’t seemed to me that Toyota has been especially innovative, but they surely have been effective in pushing down the costs and perfecting the reliability of anything Toyota.

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