The larger "V6" IFS calipers are way easier to find
It was only earlier IFS trucks from 1986-1988 that had different brakes for V6 and 4 cylinder, that's the big/big and big/small caliper and master cylinder piston difference. The early IFS caliper will have 'S12+8' in the casting and the 'S12' caliper is what came stock on solid axle mini trucks. Both the 'S12' and 'S12+8' have the asymmetrical sized pistons. The 'S12+8' has 43mm/34mm pistons, as does the 'S12' I believe.
The brakes seem to be the same on all 1989-1995 4WD pickups (4 cylinder or not) and 1989-1991 4Runner. Same 4 x 43mm pistons and finned 'S12W' castings, same 1" master cylinder, same dual diaphragm booster. My truck had a finned 'S12W' calipers and 1" master from the factory, just like V6 trucks. It's also possible that this was an XtraCab-only feature, but the window sticker on my truck made no mention of specially upsized brakes.
The 1992-1995 4Runner (V6 for sure at least) have bigger calipers and those are the same as what came on the T100. The rotor is slightly larger (11.375" in diameter for regular IFS vs. 11.41" for T100 and '92+ 4Runner) and thicker (about 5mm thicker, 0.79" vs. 0.985"). If you get '92+ 4Runner calipers you need to get the correct rotors to match. The casting on the T100 and 1992+ 4Runner is 'S13WB'. This will have 4 x 45mm pistons.
In all cases, just look for the casting number. 'S12W' is the standard what's called a 'V6' caliper. This matches well with any knuckle designed for the 'S12' series caliper (solid axle, various IFS, etc.) in that the corresponding vented rotors offset properly to line up in them.
The 'S13WB' calipers are quite a bit larger and won't directly fit in the dust shield space left by the 'S12W' calipers. I know for an IFS truck the 'S13WB' and 25mm thick rotors are a 100% bolt-on upgrade, though, with some trimming of the heat shield.
As near as I can tell the master cylinders are also the same for 89-95 IFS pickups and 4Runners except for what I think is the low fluid switch (mine has the low fluid switch in the cap). That difference in tanks might also be part of the ABS system, though I have not verified that.
The Aisin number to look for to get a 1" M/C piston:
- Toyota 47201-35670/Aisin W0133-1614951 (cap mounted low fluid, like on most non-ABS trucks)
- W0133-1612074 (tank side mounted switch, on T100 and 1992+ 4Runner)
- W0133-1620089 (FJ80 master)
Also, if you ask for a M/C for a 1994-1998 1 ton T100, you will get a 1-1/16" bore M/C. This was also matched to the 'S13WB' caliper, which would give you a slightly softer pedal than with a 1" M/C.
You can get replacement Aisin master cylinders through Amazon. I got one to my door for about $140 with free shipping. Toyota wants about $275 for this same master.
The FJ80 master cylinder is basically the same as the truck M/Cs, but it has additionally a built-in residual valve for the rear circuit, since the Cruiser had rear disc brakes. That is an advantage if you are running them, but makes the pedal travel more if you still run rear drums.
I believe the Aisin P/N for 1-1/16" master cylinders:
- W0133-1753966 (non-ABS T100)
There are number of boosters, too. If you want the 1-1/16" bore M/C, then you should run the booster from a 1992-1995 V6 4Runner or T100. You should
not use the 1989-1995 Pickup, 1989-1991 V6 4Runner or 1989-1995 22R-E 4Runner booster. The 1" master cylinder trucks have a different dual diaphragm booster number.
Using the bigger dual diaphragm booster is mandatory with 'S13WB' calipers and 1-1/16" masters, optional with the 1" master/'S12W' calipers. Probably best to match booster to M/C, though.
Toyota P/N (maybe still printed on the booster when you dig through at the junk yard):
- 44610-3D330 1989-1995 Pickup/1989-1991 4Runner booster (for 1" M/C, this is the one mine has stock)
- 44610-3D580 1992-1993 4Runner booster
- 44610-34030 T100 non-ABS booster
- 44610-3D610 1994-1995 4Runner non-ABS dual diaphragm booster
- 44610-3D620 1994-1995 4Runner ABS dual diaphragm booster
