Update from Our Experiences....
Two years ago I vistied with several here including Jelag (Jim) about converting a couple trailers. We did not need new comnplete axles, just he hub conversion. Kodiak and Dexter both make good products. Kodiak is much cheaper and DOES use standard GM replacement brake pads. We conveted two trailers and tested one season.
After that first season we changed another 4 trailers. All have 8K axles. We have over 100K combined miles testing this setup and it is without a doubt the way to go. I have over 50K on the disk conversion with the trailer I run. The brake pads still had 1/3 left this fall and will be run another. We run hard and run alot of gravel. We found the need to change the bottom caliper bolt annually as the gravel was hammering the exposed bolt to the point we lost on lower bolt. The braking ability is so good that we have found the trailer brakes are more then adequate when decending the big hills of WY and MT when loaded to 20K combined... . without a engine brake. The fact Disks brake much cooler then a electric drum setup helps and it alos is much easier on the axle grease/oil. We used to require a service every 12K ( one in the summer and once in the winter). We find the grease to be like new after 12K and have gone to once annual services (20 - 25K miles for some trailers).
The only hardware we changed from the orginal testing of two trailers conversions was from Carlisle Hydrastar hydraulic actuator to the newer Dexter model. We found the Carlisle units had problems with developing air in the lines requiring repeated brake line bleads. If negleted the time to get brake action increased. Upon bleading... the quick brake action returned. Also, the Carlisle unit is sensative to the in truck brake controller. They do have an additional electric component to alow its use with almost any brake control (Inlcuding the Factory Ford). The Dexter is good to go with any controller including factory ford.
The new Dexter model (old Dexter model was just a rebadged Carlisle) has a larger fluid volume. We run all Dexter actuators now. When combined with Brakesmart brake controllers, they have almost instant response and the trailer braking action is undetectable from your tow vehicle brakes. Read... . race car brakes even at 20K.
If buying complete axles the Dexter setup might be the best. When converting... . check into Kodiak.
http://www.kodiaktrailer.com/
We average $2300 - 2500 per conversion. That does not include any trade in of old parts. This includes four 8K Kodiak disk kits, brake line kit, Dexter Actuator and labor to install.
For those of you that tow alot (Like Jelag) or just want dependable, brakes... Hydraulic Disk is the way to go.
Also, any trailer we buy that requires trailer brakes... . it will only be hydraulic disk from now on.
jjw
ND