Hot Water Radiator - Valve Replacement

[Ross Stegall]

Hey BP Community,

I'm hoping replace some valves on old hot water radiators this summer once the system is drained. A little background:

1) My condo was built in 1952, I don't know how old the radiators are but assume they are original equipment

2) I have one radiator of varying size (length) in each room. The valves all appear to be something like this (link below)

https://www.grainger.com/product/1RLT3?gclid=CjwKCAjwhbHlBRAMEiwAoDA345r06WAuS0Nm7C4XhL2hr5jFGvMVTOnILGiEExIekre76xEkkr_rrRoCu1MQAvD_BwE&cm_mmc=PPC:+Google+PLA&ef_id=CjwKCAjwhbHlBRAMEiwAoDA345r06WAuS0Nm7C4XhL2hr5jFGvMVTOnILGiEExIekre76xEkkr_rrRoCu1MQAvD_BwE:G:s&s_kwcid=AL!2966!3!264955915919!!!g!437257756459!

3) Most of the valves appear to be broken, they turn with no action, or don't turn at all.

I've tried looking up some youtube videos on this but only find steam radiator replacement videos, are these interchangeable? 

Anyone in the DC / NOVA / DMV Area know a good company that will do this for a reasonable price? I can't seem to find any companies that will touch this. 

Will fixing the valves fix the problem? Or are these so old they are no longer good and the whole radiator needs to be replaced? 

Thanks all, any help is appreciated.