Normal way to rebuild these front struts, is to use a replacement cartridge type insert. You remove and discard the old internals, and simply insert the new cartridge. Most come with new top nut, but best hang on to the old one. These were normally available from Woodhead - part no CW705, and they also fit 100E range, using a spacer that comes with them. Girling also made them - part no 5005. They have long been obsolete, but NOS parts do turn up - check ebay in UK.
It was normal to rebuild the internals, but parts to do this are long since gone. Complete struts can sometimes be found as NOS in the UK, but shipping costs to US would be prohibitive
There is a supplier in the UK, Small Ford Spares, who list inserts at £60 each, and they may be new build stock, as they are into remanufacturing stuff. They mainly do for the old upright sidevalve English Fords, but have an expanding range of 105E stuff. try
www.smallfordspares.co.uk
If your old units are not actually leaking fluid, but just a little tired/weak, it may be they are just low on fluid. There is a hexagonal head bolt/plug on the strut body, which can be removed to top up the fluid. If you can get proper hydraulic shock fluid use it, failing that use the hydraulic oil that you would put in a hydraulic floor jack - it's much the same stuff. If you wanted to upgrade the damping, try a slightly higher viscosity oil, but don't go too thick.
good luck