C179 is a tantalum cap that often goes bad in these 858 chassis. Replace it with an equivalent value electrolytic cap.
Sonoma is also quite right, all/any 10v rated cap should also be replaced.
In general, any tantalum cap on the board is suspect as well. They are electrolytic in nature, just like the can caps are.
It's an old radio; and electrolytic caps are subject to failure. They didn't use high grade caps in this radio when it was produced; this goes for any CB radio as well. If you intend to make this radio a daily driver; then replacing all of the electrolytic caps ensures a better chance for a trouble free future.
I've recently rebuilt an 858 SSB chassis (TRC-458) and replaced all of the electrolytic caps, even all of the tantalums. Klondike Mike (forum member here) sells high grade/quality complete cap kits and will give you a $1 off because you are a forum member. Bought my cap kit from him, and this is how I know what he sells. Good stuff!