Clutch hose confusion

[superstator]

I've thoroughly confused myself here.

I have what appears to be an early-type IIA clutch master, the fittings for which are threaded 7/16-20.
I have what should be a late Defender clutch slave, the fittings for which are also 7/16-20.
I have a length of 1/4" hardline, and one each male and female nuts, threaded 7/16-20.
I have a brand new IIA braided clutch hose (RNA606), which when I went to test fit things I discovered is threaded 3/8-24.

What gives? Did I just order the wrong hose somehow, or am I missing something fundamental?

[SafeAirOne]

I doubt that anything 90/100/Defender is 7/16-20. Everything on those vehicles is metric, AFAIK.

Have a look at the front of the SIII Workshop Manual. The differences/identification of metric and non-metric lines and fittings is spelled out there.

[superstator]

I doubt that anything 90/100/Defender is 7/16-20. Everything on those vehicles is metric, AFAIK.

Have a look at the front of the SIII Workshop Manual. The differences/identification of metric and non-metric lines and fittings is spelled out there.

Everything but the clutch, apparently. It is definitely 7/16-20, verified both by measuring with thread gauge and dial caliper, and threading in a 7/16-20 flare nut.

[superstator]

Doing more digging - it seems the master and slave cylinder were 7/16-20 through at least 1994, maybe 1998. On the Series and early Defenders they used adapters to size it down to 3/8-24 fittings and 3/16 lines. Sounds like it wasn't fully metric until the TD5 came along.

Tempting to bodge a bigger flex line, but it sounds like in the interest of sanity I should just get the 3/8 adapters and keep it simple.