bronconut is right on the money and steers you straight regarding some pros and cons.
The biggest concern I think you mention is some possible funky motions during emergency braking. Unfortunately, as good as the drums can be, unless their automatic adjusters continue (or even start!) to function properly, your concerns are valid. Discs are much more consistent with their self-adjusting characteristics.
But if your truck is modest in it's build, not running huge tires, the drums stay adjusted relatively well, and you know what you're doing behind the wheel, it's not that bad.
That issue with drums is the potentially uneven braking if they're not adjusted properly. This was never an issue for me, because I was literally under my truck every other week making sure that all four drums were perfectly adjusted at all times.
Most people are not going to get that involved with their rigs though, so that might help with your decision if yours work or not.
Luckily here though, your rear brakes don't have near the effect that your fronts do, so even if they get a little out of sorts, it's much more controllable than if your fronts were not in perfect shape. With the front discs though, this should never be an issue unless they were installed incorrectly or you let them wear down to far or something like that.
How long have you had yours? Sounds familiar though, like from last night's discussions. Is this one that you just brought home? Or have you had it awhile?
If new to you, maybe check some characteristics, drive it awhile, and see what you think about how it feels.
From a purely maintenance standpoint, the discs have it all over the drums. Period.
Drums are reasonably powerful when in good shape, basic, last a long time and are self-energizing to an extent, which gives them some power. But drums have more little pieces to mess with during routine maintenance, and as mentioned, can become misadjusted easily if everything isn't working just perfectly.
That along with the wet performance is why I'm changing to discs in the rear. I waited until I had to replace the drums too however, as I didn't feel any emergency need and don't like to waste perfectly good parts unless I have to.
For swapping, price-wise you might still be ahead if you go for the inexpensive kit and upgrade your axle shafts separately. But remember too, upgrading axle shafts to include the 31 spline option means you need to change out the differential carrier, or at least it's side gears. All EB's were 28 spline from the factory.
Unfortunately for me (price-wise that is) I opted to go for the kit with axles included because I've had such good luck with the parking brake style used in this kit, thought it was a good balance size-wise and I like the axles.
It's got an internal drum brake that rides inside the rotor hat. With all the varied positive and negative feedback on various parking brake types (including stock drums I might add), this one got my vote. Even at more than twice the price.
So, pros of drums?
Leave it alone and it doesn't cost you a thing.
Enough power for most EB's until you get to much larger tires.
Service cost is pretty close to the same for standard replacement of shoes vs disc pads for the do-it-yourselfer. Usually a bit less than discs when having some shop do the work for you. But it really could go either way depending on what parts need to be replaced. The drums themselves aren't exactly cheap, but don't need replacing very often either. A resurface is about the same cost for drum vs disc around here.
Cons?
When maintenance is needed it's a bit more fiddly, but we've been doing it for a hundred years so it's nothing new.
Crappy when wet.
Crappy when hot, but this depends a lot on materials and is not an apples-to-apples comparison between drums and discs.
Inconsistent unless adjustments are kept after and near perfect.
Pros of discs?
Equal or better stopping power.
Much better consistency.
Much better performance when hot or wet. Especially wet!
Much easier service/maintenance if no resurfacing needed. Hands down!
Replacement costs similar for similar wear.
Looks cool.
Probably lots of stuff I'm overlooking, but that's just some additional thoughts from the Farside... As said, I'm going the disc route myself, but that doesn't mean it's hands-down the way to go for everyone.
Good luck on the decision.
Paul
