I usually get mine from eBay. You can get used Cat dealer Parts Manuals, Repair Manuals and Operation/Maintenance Manuals from there. Make sure you get the manuals that go with your machine's serial number. Take a pic of your serial number plate and keep it in your phone, you'll need it often for just about everything you need. Often times manuals are available on CD discs or as digital downloads as well, but quality with those varies sometimes. I bought one CD manual that ended up being screen shots of just about every page from the Cat SIS system from somewhere. It was better than nothing, but not as good as an actual manual IMO.
If you plan to buy an actual Cat Service Manual, look around at them, because some are more complete than others. A complete one will have a copy of the Operations/Maintenance Manual in it (so you wouldn't have to buy it separately or end up with two like I did once) and also fold up wiring diagrams and so forth. I got my 426B manuals off of eBay so a 416B should be available I would think.
First call your local Cat dealer and give them your serial number and have them give you a price for the Operations/Maintenance Manual and Parts Manual directly through them. That way you will know if the prices you are seeing on eBay for used ones are a good price or not. I don't think you can order the Service Manuals through the dealers so those you just have to look for the best prices you can.
I just ordered a Parts Manual for the dozer I bought and the price through the Cat Dealer was $146. There is a guy on eBay that wants like $190 for one, because it's the only one on eBay that fits my particular machine right now. I ended up buying a CD parts manual for $90 and am hoping for the best.
