I just rebuilt my knuckles, and wheel bearings on my 40. I left the dustshields off! Is this a bad decision? Are there any downsides to leaving them off? Any input here is appreciated.

I don't think that leaving them off is a good idea, the dust shields are there to keep dust (hence the name) and dirt and to a small degree water,out of the birfield chamber. The birfields do not have a boot on them like a CV joint does,so you need to protect them! When you say dust shield are you talking the felt or the rubber or bolth?

Talking about the metal shield behind the rotor, all of my felts, and paper gaskets are there.

IIRC, the metal shield is required for spacing of all the seals/gaskets/etc. However, I trimmed the entire bottom off mine on installing, leaving only the portion required for bolting them on and for the caliper hoses.

woody thanks for the input on that that is what I was worried about, was the spacing, but with the shields off I haven't seen anything leaking. Yet.... I am going to keep a close eye on the knuckles for a couple of weeks for leaks, if none I will leave them off, but at the first sign or a leak they are back on really quickly. Maybe I'll just cut the flared part off, and, like you said keep the mounting surface for spacing.

DOH no star yet!!!