Rear drum to disc conversion question, Do I need to do anything with the master cylinder? Options

[GriffGirl]

Someone told me he thought I will need to do something with/replace my master cylinder when I convert my rear drum brakes to disc brakes; something about the proportioning valve.

Here's what he said:

In regard to your brake swap, I could be wrong, but I'm almost positive that you'll need a different proportioning valve...When you do it, though, you should see about swapping the proportioning valve and
master cylinder (if it's different on the GTs)... Drum brake wheel cylinders and disc brake calipers use different amounts of fluid (typically) and if you swap from the former to the latter, your rear discs brakes won't be doing as much work as they should.

This is all greek to me. Help? Is this something I should look further in to?

[alltracman78]

For something like this you can't use the online stuff for 1sttoyotaparts, it's not even close to complete.

Part #s for the proportioning valve.
47150-20370 ST W/ABS
47150-20280 ST W/out ABS
47150-20240 GT

Originally there were 5 different proportioning valves, but Toyota superseded several part #s.

The master cylinder is also different, but only for ABS or non ABS.
I assume the ABS cylinder is larger, like it is on the 5th gens.

47201-2B090 W/out ABS
47201-2B050 W/ABS

These are for a 94 Celica specifically. Dunno for other years.