how hard are slave cyls to replace?

Hey i did a bunch of searching on here about slave cylinders, looks like since mines a 99 i have an external one so it should be easier, just curious if any of you have replaced on of these and if so if its hard to do or what? mine leaks a lot, i have to re fill it often, but whats worse is the clutch engages really mushy and doesnt feel right. my mechanic said my clutch looks fine but the slave is leaking. im guessing its getting air inside the lines, sometimes ill go outside to start it and hte clutch will be to the floor, ZERO pressure. ill have to pump it and eventually after like 50 or so pumps it will gradually re presurize and be fine again, really annoying though. Anyway, just wanted some imput!!!!

yep air in the lines. Just like air in your brake system will cause mushy to no pedal feel. All you got to do is replace it and bleed the clutch just like you would your brakes- pump the pedal some, hold it down on the floor and crack the bleeder screw.
I had to replace my slave cyl twice and the 2nd time it was a bitch to bleed out...

I just replaced both master and slave on my 1984 pioneer. The slave had 2 bolts holding it to the transmission (ax5) and the fluid line. The hardest part of taking it out was getting the line fitting loose without stripping it with the wrench, I'd advise you to invest in a line wrench made for that purpose. The hardest part of reassembly is bleeding the system. You need two people to do this effectively. It also helps to compress the slave piston inward with a socket and a c-clamp while bleeding the system then slowly release it letting it draw in the fluid.
(Watch the fluid level closly so the system doesn't draw air.)

hmm.. seems like something pretty easy to do myself... what are the chances the lines leak too?

May i suggest getting a bleader system, like with the preasure gun and whatnot, i just got to bleed my Clutch system yet again last weekend and i swear its the last time i lay down there with that nasty brake fluid oozing down my arm for ten minutes.