I can't really put my finger on the cause, but am quite familar with screws not wating to come out of the overflow.
When you finally do get the screws out, see if you can find suitable replacement stainless steel screws.
Get some "copper rich" antisieze from a plumbing shop or auto supply store and apply a little to the threads when you reinstall them (hopefully new screws).
After 40 years, a new tub drain may also be in order, but depending on the location, that can involve a great deal of work.
You have to remove the "large" nut but you need to find a way to hold the faucet. Also, you will see a retaining washer that fits on the inside of that "large" nut. If you loosen this it will release some of the tention on it and hopefull make it easier to remove. Also, try using some lime remover on the unit will might alow the retaining nut to loosen. Good luck and if you can't get it off, contact Kohler, they have an 800 number and they can give you the info you will need depending on your model.
Question edited for correct spelling of maker 'Noen' to 'Moen'.
'Fix' as in it is leaking? Or tighten it down because it is wobbly, or something completely different?
Well, we can have a one on one seminar by the internet. I've been a pumpman for 20 years. I can share with you my experience (household pumps, suibmersible pumps, turbine pumps, gear pumps, piston pumps, dewatering pumps, mud pumps, trash pumps, mining pumps, solids handling pump, etc....) Just take your pick. Just send in your e-mail for assistance. God bless.
It is leaking due to a defective mechanical seal. It needs to be replaced. To replace it, is to take the pumpcase off by taking off the bolts that hold it. Then, take the impeller off to take the mechanical seal behind it. Put the replacement in, and reassemble the pump. Just get in touch with us by e-mail to get more assistance.
Move the lever or turn the knob. Check the stop tap under the sink. Make sure the faucet control knob or lever is tight, There is normally a removable cover that hides the screw..
