If the leak is at a point that can be tightened or loosened, I would remove the part, put a fair amount of teflon tape on there, and put it back on. May take a few tries to get it right (if you put too much tape on it will be too hard to tighten, too little tape and it will leak). If the leak is at a point not designed to come apart then contact the mfg for a replacement. As far as installing a replacement, without a picture I dont know if your sprayer head needs to be attached to the wall for support or if you just tighten it on the stub out with teflon tape.

Call 1-800-BUY-MOEN, and get a new part. THEN, maybe, put a couple of wraps of Teflon tape around it when you replace the old part. Why fudge a worn part when you can get a new part, no questions asked, for free in about four working days.

Thanks for the info, both of you. I did call Moen, and they sent me a new hose unit. On the phone, she told me how to change it. It's pretty straightforward, it all just unscrews. Great company!