Try the
Parker Tube Fittings Catalog.
You're probably going to need two adapters; one to reduce the 3/8'NPTF & the other to screw into it and adapt to M12X1.5. If you poke around in there, I bet you can make something that will work without resorting to cutting lines and using hose clamps. Check out pg. 14.
The original Toyota fittings are steel (not brass) and were plated with cadmium.
The Parker fittings below are also steel but zinc plated, which is not quite as corrosion resistant as cadmium.
This is what I found… (as an example.. not sure if this is what you are looking for):
First adapter will reduce the 3/8-18 NPTF to 1/8-27 NPTF
Parker PN: 3/8 x 1/8 PTR
(this fitting is also available in stainless steel with a different PN & MFG from
MSC Industrial Supply
The second adapter will screw into the 1/8-27 NPTF and leave you with a M12X1.5F
Parker PN: 1/8M12FHG8
If you web-search the part numbers want, you can find a vendor.
but..............check out the catalog and find the fittings you want to make sure that those are what you are looking for... The PN's above are only an example.
Hope that helps...