You mean the dust container that you take off to empty or the part with the wheels and the brush in it?

Found the power supply caps on the main board can fail after 10 years or so. They are easy to replace and there is an excellent teardown page on this site.

Follow the link Linksys BEFSR41 Teardown

Thanks Ryan. Couldnt figure out how to get the case off until I checked here.

My BFSR41v2 teardown was identical so was able to replace the two 1000uf caps shown in step 5. The router gradually lost speed and finally quit altogether and wouldnt reset. Found the first cap had 5v AC across it and felt warm. The second cap was ok but replaced it anyway and the router is like new. BTW I was using it as a switch behind my wifi router to get more ports on my wired LAN.

Theres a good description of how to repurpose an old rouiter as a network switch on the How-to-geek site.

Cheers