I stripped the threads on my low side A/C valve and was able to avoid buying a new low side hose by using and adaptor valve from a local A/C supply house. A reliable ebay vendor is
http://stores.ebay.com/Frosty-Freeze-A-C-Products-Company. On his web site he lists both straight and 90 degree adaptors(Part# CPS-AD36C ,Part #FJC-6092) that I believe will work.
I would describe your problem to him and he can offer advice. If you have converted to R-134 coolant, you may need different adaptors.These adaptors have valve core depressors on the female side,so they should allow you to leave the old, leaky valve in place and avoid opening the system. The valve core exchange tool is readily available online (approx$32,ACKits.com) but I went cheap. My adaptor valve has not leaked in 2 years of use. I suppose that the two valve cores in series will slow down your recharge time due to flow restriction. Hope this helps.