EDIT: I have to apologize for a brain fart earlier; my previous posts referenced 80 series hubs; I had 80s on the brain while I was reading.
The 40 series hubs are NLA (why can we get hood hardware and fender badges, but not hubs), however, you can get used:
BTB (the old Man-A-Fre) has them:
View attachment 3369225
Classic Cruisers in Poncha Springs, CO may have them too.
That's a really good question. Those "pins" are hardened dowel pins; they're pressed in and if they're broken, there's no way I know of, short of cutting the hub, to remove them. Of course, that would defeat the point of fixing the hub...
Dowel pins are typically used to locate two components, relative to each other, so that they can be attached, usually by means of screws of bolts and nuts, or in this case, studs and nuts.
The hub subassembly should have been provided with two dowels, presumably to use as drivers for the drive flange - the idea is that the drive flange needs a reaction arm, in this case two, so that when the driveshaft splines turn, and thus turn the flange, the hub turns with it. You'd think that with six studs to engage the drive flange, it would be pretty well attached to the hub. Toyota engineers probably felt that the purpose of the studs, cone washers and nuts were to provide the clamping force necessary to securely attach the drive flange to the hub, and that for off-road use, additional torsional reaction would be needed.
This is because the holes that the studs fit into are clearance holes, and the drive flange would have to turn a bit to engage the sidewall of the hole with the stud, in order to "drive" the drive hub via the flange. The dowels, on the other hand, are press fit into the hub, just to keep them from falling all over the place during hub service, and slip fit into the drive flange. If you place a drive flange over the hub and engage the pins, you'll notice there is no rotational play between the two. This keeps them in constant contact and lessens the shock load when the driveshafts change rotation, or the load is released and reapplied, such as when you work the throttle back and forth.
FWIW, the clearance holes are part of the reason for the cone washers.
Short answer, if they broke on the trail, I'd drive it out, but I'd be careful with it. If they broke on the road, I'd place finding out why high on my list, and replace the hubs as soon as I could. If you're driving only on the road, you'll probably be OK for a good while. It's entirely possible, if one or more are gone, they just fell out. You can buy standard metric dowels and replace them, if they aren't broken (sheared off) in the holes. There's nothing magic about them.
You can buy new hubs (unfortunately they come with bearings, but not studs), or just replace yours with used ones.
@slow95z or
@arcteryx can probably help you out.
Toyota sells the dowels, but for my money, that's like buying Toyota gasoline. Dowels are dowels.
They look to be Ø7-mm and maybe as long into the hub as out - 20-mmm maybe?
