I got new cylinders for my truck ('47 1.5 ton) from truckandcarshop.com. The rear ones were made in Argentina (by the lowest bidder I guess). The quality overall was fine but I had to file the indents around the adjuster wheel as they were roughly cast and didnt work well with the adjuster wheel on the backplate. Otherwise I have no reason to doubt them. They are on the truck (which isnt mobile yet) but I have stress tested them (as much pressure as I can get on the pedal) and nothing happened.

Miner were too far gone to rebuild but the choice of new ones comes down to budget. If yours are rebuildable I think its a good option.

'47 Canadian RHD 1.5 ton truck