25 minutes ago, EuroDat said:

No. The link Steve posted is for the S12W calipers with the 4x 43mm bores and vented rotors. Your calipers in your post #6 are the S12-8 calipers with 43/34mm bores for the non-vented solid rotor.

The S12-8 calipers are getting hard to find.

S12-8 - 1981-89 Toyota 4 Runner

S12W - 1990-95 Toyota 4 Runner

Thanks for pointing that out. The 12+8 are available on Rockauto, too. https://www.rockauto.com/en/moreinfo.php?pk=13416221&cc=1277243&pt=1704&jsn=1404

 

23 minutes ago, MH77280Z said:

I am currently running after market calipers from Oriellys. They are 2 piston and stock bolt pattern. planning to continue using those. Will get these rebuild in that case. I think rebuild i am quoted $50 a piece which includes blasting, painting, new kit and assembly.

They are bolt on replacements/upgrades, but you will have a deeper brake pedal due to the extra fluid required in the calipers. That can be corrdcted by replacing the 7/8" master cylinder with a 15/16" 280ZX master cylinder.

If you go to the S12W with the 4x 43mm pistons, you will need the vented discs and the 280ZX 15/16" master cylinder or the 1" Wiilowood MC.

The 280ZX MC is slowly but surely becoming a unicorn.

33 minutes ago, MH77280Z said:

I am currently running after market calipers from Oriellys. They are 2 piston and stock bolt pattern. planning to continue using those. Will get these rebuild in that case. I think rebuild i am quoted $50 a piece which includes blasting, painting, new kit and assembly.

I missed your first post, I see that now.

So, basically, you're planning the Toyota caliper conversion.  Better study all of the fine details that EuroDat is supplying.  

Are you going to paint them red?

5 minutes ago, Zed Head said:

I missed your first post, I see that now.

So, basically, you're planning the Toyota caliper conversion.  Better study all of the fine details that EuroDat is supplying.  

Are you going to paint them red?

I am not planning to put these Toyota ones back on. I am staying with the 2 piston oriellys, they have been fine. I dont race.

I just thought may be these 4 piston ones are OEM and they are not.

Another tip.

Be carefull buying a replacement set. A lot of sellers really don't know what they are selling. You should look for the S12-8 system.

Calipers are left and right, marked with a R and L. There should be two sized pistons. 2x 43mm pistons and 2x 34mm pistons. That is not a typo no matter what the sellers tries to tell you. 4x 43mm is the Wide version and won't work on the 10.5mm thick solid rotor.

Buy a set of Porterfield  pads R4-S brake pads. Well worth it.

24 minutes ago, MH77280Z said:

I am not planning to put these Toyota ones back on. I am staying with the 2 piston oriellys, they have been fine. I dont race.

I just thought may be these 4 piston ones are OEM and they are not.

So you're planning to sell them or hang on to them?  Hence the rebuild?

They look crusty.  I'll bet when you get them apart you'll find that a simple rebuild won't do it.  Somebody might buy them for cores though so that they can do the conversion.  Good luck.