D4 7u

Got another question for you guys I've found a mid 50s D4 that's been sitting for awhile, I have not looked at it personally just saw some pictures it looks pretty straight for the age. The problems are 1 track won't stay tight the owner thought the spring was broke but couldn't remember. If this is true how hard is it to replace? The other issue is one track was weak which I'm assuming is a steering clutch or possibly from sitting? The current owner acted like he hadn't really used it as he bought it off a neighbor I think it's been converted to direct start but am not sure. What's something like this worth? thanks guys

D4 7u