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Mismatched calipers and rotors


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I'm about halfway through upgrading my brakes and just noticed the rotor is way too thick for the caliper.



One side already has the rotor installed and I painted both calipers. Calipers are AC Delco 18FR247 and 18FR248 for an 85 4runner. They have S12-8 stamped on them. 


I got the rotor from silvermine as well as the spacers.

Did I get the wrong calipers? Or am I supposed to just run the stock rotors? 

Edited by calvinhg
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The page you linked says the rotor only works with the Stage 4 kit.  The Stage 4 kit page says that the calipers are huge.  Can't tell what brand they are but that looks like the cause of your problem.




Stage 4 drilled, slotted and vented rotor.

This rotor is zinc plated to prevent rusting.

10.8 inches in diameter. 22mm thickness.

Only work with stage 4 front brake kit.


This brake kit comes with the following parts:
1. Enormous 4 piston calipers (43mm pistons)


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That is the problem with the toyota calipers. It can be difficult to find the right ones. Some will take the vented rotors and some will not. Even though they are marked the same.

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I went to O'Reillys and matched the uninstalled rotor with calipers for a 91 4runner v6. There are two options for 91: 

- to 05/91 (pn 19-1240 and 19-1241) that had s12w stamped on them

- from 06/91 (pn 19-1600 and 19-1601) that had s13w stamped on them

The rotor fit on both. The only difference I saw was the piston size: 42.7mm on the s12w and 45.3mm on the s13w. 

Didn't buy them because they were just the basic O'Reilly brand but now I know what I need. 

Edited by calvinhg
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Sounds like you sorted this out but it was my understanding that the +8 caliper was for the non vented stock rotor and the W was for the wider vented rotor. 

I have had mine on the non vented rotors for some years now and may recall incorrectly. 

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That’s correct. The +8 also has two different pistons where the “W” series had both larger pistons. Parts are still readily available from Toyota for a rebuild.

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