[69TowRig]

'69 and '70 Blazers had open knuckle D44s. My '69 was not closed knuckle like everyone says it should have been, and I have not seen a '69 K5 with closed knuckles.

The problem with a spindle swap is that drum-brake knuckles have the six bolt holes clocked differently than the disc knuckles do, so a straight spindle swap is not quite so simple. The disc-brake backing plate will put the caliper in contact with the knuckle itself. You *could* grind away a lot of material and make the caliper fit, or swap the entire knuckle off.

If you do the knuckle swap, you can use any 1971-later D44 or Coporate 10-bolt for donor parts. It is closest to "bolt-on" if you use the matching outer axleshafts from the donor axle.

I did the knuckle swap last year on mine. I pulled the knuckles from an '84 K5, bought reman calipers and paid up for a set of Crown brake lines through xtremecrawlers.com. I re-used my original outer axleshafts but was not able to install the retaining clip for the shafts under the lockout. If you go the same route as I did you end up needing 1" long 7/16"-20 bolts with fender washers to retain the axleshaft from moving back and forth (the ends of the shafts are threaded)

The knuckle swap will cost you some $$$, I had to replace the balljoints, an axleshaft u-joint, and a couple wheel bearings too. Lots of time invested. In the end you get disc brakes but still have the smaller u-joints ('73+ have larger axle u-joints). The spring perches are the right distance apart on the '73+ trucks, and it is a straightforward swap if you go that route. A bonus is that you automatically get the lower mounts for a swaybar if you want to add one of those to the truck as well.

Overall, with the power booster and discs up front the thing stops way better than it ever did before, and the effort is worth it.