Kenmore Range has (2) burner knobs that do not turn, 362.75212100

[lqqk_out]

Hi!

In one of my rental apartments, the tenant mentioned to me that two of the gas range burner knobs do not turn.
I went to look at the appliance, and the far left and far right gas burner knobs do not turn. They seem to be frozen shut.
The appliance information is:
Make: Sears Kenmore
Model Number: 362.75212100 (GE)
Serial Number: 1F133337P

Has anyone seen this type of problem? Is there some type of adjustment I can make or maybe something I need to lubricate to fix this?
Or do I need to replace the two top burner valves?
Also, could someone provide me a link to the "Repair Parts List"?

Any information/help is greatly appreciated. 

Brett

[tcarmen]

Can't find the parts diagram anywhere, which is weird.

You can call searspartsdirect and they may be able to look it up on microfilm, but the valves will probably be expensive or not available. Valves for other 362* ranges run about $75 each.

[lqqk_out]

I wanted to post some follow-up information.
I sprayed some WD-40 into the valves to loosen them up. One of the valves did loosen up, but the other valve is still stuck.
Next time I stop by the apartment, I'll trying spraying some PB Blaster into the valve. I've had success in the past using that penetrate lubricant on various stuck fasteners on automobiles.