These calipers have bigger pistons and will take a bit more fluid. I normally run a 1" master and 4wheel disks. and they will require a slight trim of your backing plates, Very simple to do. if you don't want to upgrade calipers as large then go with 1985 FJ60 calipers or something similar. Slightly smaller pistons and probably will not need the larger master to feel correct. The smaller calipers take different pads as well.
Hoses will stay the same regardless if you bypass the backing plate hard line. Reason for this if you ever do any service you can remove the caliper without breaking the fluid system. I normally run backing plate deletes or cut the backing plate off and use the remains as a "spacer" or basically make my own delete plates.
Calipers I normally upgrade to, 89 4runner, need pads and pins as well.
I get calipers local and use my old cores to avoid shipping cores back. These pn's were Oriley auto or Rock Auto.
Front Caliper BrakeBest Brake Caliper 19-1240
Front Caliper BrakeBest Brake Caliper 19-1241
Front Hose caliper to axle RAYBESTOS BH38881 (bypass the old hose and hard line and go directly from axle to caliper)
Hose Frame to axle (extended rubber drop hoses) RAYBESTOS BH38009
Prop Valve
Summit racing PN Wilwood 260-12627 $40
To bypass the LSPV you will probably need to run a longer hard line to go to the rear drop hose when bypassing the LSPV circuit. You will see this if you trace the system. It "loops" back to the front when the truck is at an extreme angle nose down. the junction block up front has too many fittings and returns rear brake pressure to the front system or something like that.. I seem to recall using a brake bleeder to fill the extra hole or used an FJ40 junction block. It's been a while. then made a new hard line that extended to the rear drop hose and bypassed the whole shebang. Also shaved about a pound of parts off the truck by removing. That has to be good for mpg ?
I keep a spool of brake line and have a super cool double flare tool so for me it's a simple job.
https://www.amazon.com/dp/B01HOXH242?tag=ihco-20
not the exact one i have but they put different names on the same tool.. Eastwood rebadges the tool and charges more..
So.. FWIW, I would bypass the LSPV, install a rear adjustable prop valve, simple to mount under the master inline with the now ONLY REAR brake circuit. and install new calipers and hoses and probably a master.. Then you know everything is new, updated, safe. You will need to dial in the rear brakes after all this.. Normally involves gravel lot, a spotter and lots of test hits with the brakes.
I would also quit worrying about a "foreign market" master cylinder. I just cannot see that toyota would use a country specific brake master..
I'd guess with the purchase of the tool if needed, your looking at about $500.. without the tool probably $300 or so to be safely stopping again.
But.. It might have been as simple as the current master you have being put together incorrectly and the piston is not in the correct location. Don't know if you tried the little bolt on the side adjustment or not.
Good luck! Let us know how it goes.
