i am not a plumber , and dont play one on tv, but i do play one at home, when nobodys lookin.
most of the valves (i have seen) can be, disassembled from the front without having to tear the wall/sink/frame/tub down.
but, you didnt even mention what type it was?
Is it a 2 valve system? or a swinging/twisting around single, or a lift up single? is it one of them thermally controled no burn ones, they have adjusters?
Pull the plate , do it, i know you can /ubbthreads/images/graemlins/smile.gif and watch out VERY carefully for that brass stuff, if there is slotted rings to remove, without a good tool you can really shred the brass and copper.
so if you dont have the exact tool, and it doesnt give easily with the cruddy tool your using, then get a tool to do it.
ok so i will just say dont ask me how to do it with a hammer and a screwdriver, because the TOOL would have worked without damaging stuff. /ubbthreads/images/graemlins/blush.gif
use well fitted sockets, or box end wrenches, i wont tell you how to put big claw marks in it with a monkey wrench either or how to round off a brass nut /ubbthreads/images/graemlins/crazy.gif.
use well fitted screwdrivers, i wont tell you how to mess up a brass screw with a swiss army knife /ubbthreads/images/graemlins/wink.gif
beware that not all threads in this world are "right handed" stuff that would unscrew with normal operations , might have reverse threads. of course they always put reverse threads in just to mix up us amatures /ubbthreads/images/graemlins/ooo.gif
once you get inside, if the blockage is back in the holes to far, break it up with something then run a blast of water across it.
replace any rubber used when your in there, even if it works today, that might already be what is stopping proper operation.
if a plumber can do it, then i can, and when i get done i will have the tool TOO /ubbthreads/images/graemlins/cool.gif now getting good PARTS, that is the hard part /ubbthreads/images/graemlins/mecry.gif.
anyways there is some extra tips from a moran who has ruined about anything , but still got it to work better than ever /ubbthreads/images/graemlins/smirk.gif