How to replace tub fixtures

I recently moved into a 1920's bungalow. The upstairs bathroom has a tub (2 handles) but no shower. It takes lots of force to turn either knob on and even more force to get the water to shut off completely. The handles look much newer than the drain plate and tub drain switch so my guess is that she just replaced the handles before she sold us the house. Do you all think the entire fixtures need to be replaced or can any part of the fixture be lubricated? I looked at HD and saw replacement kits for Price Pfister, or Moen fixtures but none for Kohler. How do I determine what needs to be replaced? I've done basic faucet replacements and drain repairs but have never soldered coppper pipe.
Thanks for your help!
Mike

You need to remove the handles, flanges, and valve stems. Replace the bib washer on the valve stems and grease the stems with plumber's grease.

I apologize for my ignorance. After removing the handles, how do I remove the stems? Do they screw out? Are the bib washers a standard, universal part or do I need to find one that goes with my particular fixture? Any guidance would be much appreciated.,
Thanks!!
Mike

Removing Valve Stem

You need a set of inexpensive plumber's sockets to unscrew the valve stems, using a large crescent wrench for leverage.You may also need a handle puller to get the handles off. You can pick up an assortment of bib washers for a couple bucks or you can bring the old one to a hardware store to match it up exactly. The flange or "escutcheon" may screw out or pull out depending on the model.

The bib washer is located on the bottom of the valve stem and is screwed on with the bib screw. Get some plumber's grease and lubricate the inside threads of the valve stem before reinstalling it.

I finally got some time to work on this and am stumped. I attached a picture of the entire unit (1st picture) and then after I took it apart (2nd picture). I found a Kohler bath stem repair kit (pic 3) which says it includes: flat washer, bib screw (not shown) top bib ring, bonnet packing, and a cap thread gasket. I also got an assortment of flat washers and beveled washers. The problem is I didn't find anything resembling the black rubber washer or the large rubber tube-like thing anywhere in the original assembly. I'm wondering if the bib washer is the part in (pic 4) and if it goes somewhere on the piece next to it. I tried just greasing the threads of the valve stem which did help it turn more smoothly but I felt I had to really crank it hard to get the water to turn off completely. If the bib washer is what I have in pic 4 does it go inside the piece next to it so the threaded end of the stem meets it when everything is assembled? Hope this makes sense.
thanks,
Mike

stem

Get a Kohler Valvet assembly, even if it has a short stem and use it with your long stem. Be sure to get the right thread direction because they come with both left hand and right hand threads but the left hand is the most common unless you have lever handles in which case you need a right hand for the cold side.

This is what I found online:
Brass Craft Explosions page 33 parts 1, 2 &3

Brasscraft stems page 3 middle of page
Are either of these what I'm looking for and if so where can I get them. I don't remember seeing them at my Home Depot. Any place online that you would recommend?

Thanks,
Mike

Fixed it!

I ended up soaking the assembly in santeen and got to the bibb washer. Replaced the washer and the seat in both assemblies which did the trick. Can't figure out how to close the thread. Thanks for all your help!!
Mike