Thanks for your recent article on swapping disc brakes onto a GM 14-bolt [“Dol-Drums,” Sept. 2018; click here]. I have contemplated this upgrade for my restored 1977 Chevy K20, but my only hesitation is that I will lose my emergency brake. Any ideas on how to retain an E-brake with discs?
A 14-bolt disc brake conversion is a popular and fairly simple upgrade for any full-floating 14-bolt. Not only do disc brakes improve stopping power, but ditching the drum sheds about 50 pounds per side, too. Retaining an emergency brake with a disc conversion is not only possible, but there are a couple of ways to get the job done.
Just about all of the disc brake conversions on the market utilize either light-duty 1/2-ton front calipers (JB6) or heavier-duty 3/4-ton calipers (JB7). The JB7 calipers were used on heavier-rated trucks and use different brake pads, but they physically interchange with JB6 calipers in terms of mounting. In addition to these options, you could also use 1976-1978 Cadillac Eldorado calipers, which have a parking brake function built into the caliper. At one time these factory calipers were nearly unobtanium, but these days a couple of different companies manufacture these calipers, making them much more common and affordable. Although they don’t offer quite the same holding power, these calipers are a viable option for those who want to retain the use of an emergency brake or need one to pass state inspections. You might need to get a little creative with the cable routing and length to reach the calipers, but Eldorado calipers offer a fairly simple bolt-on solution and are compatible with just about every conversion kit on the market.
A second option is to move the parking brake to the back of the transfer case. You didn’t mention which transfer case you have, but if it’s the original one in your 1977 truck then it’s likely an NP203 or NP205. A few different companies offer a driveline-mounted emergency brake: Northwest Fabworks (northwestfab.com), High Angle Driveline (), and TSM Manufacturing (tsmmfg.com). Though there are some slight variations, all three of them add provisions to mount a thin rotor and a mechanical caliper to the rear driveline at the transfer case. These will require some driveline modifications in addition to modifying the stock emergency brake cables, but they are reported to offer superior holding power and are a viable alternative to tracking down the Eldorado calipers. Either of these options should satisfy local laws as well as those concerned about having the added safety of an emergency brake.