Front disc brakes became standard on the CJ-7 in 1977. The Dana 30 with disc brakes uses a 10.5 in. rotor on a 5x5.5 bolt pattern, and the procedure is the same as any other vintage 4x4 disc swap — pads in 90 minutes, full rotor service in 3 hours.
There are two distinct caliper generations to know about. 1976–1978 CJs used a six-bolt caliper bracket that bolts between the steering knuckle and the spindle. 1978.5–1986 went to a two-bolt caliper mount where the caliper bracket bolts directly to the knuckle. Year cutoff matters: order parts by VIN, not by model year, because the changeover was mid-1978.
Pads on the 1978–1981 trucks use a two-bolt caliper plate. 1982–1986 CJ-7s added a titanium dust shield behind the pad — same caliper, different pad backing plate. Crown Automotive part numbers reflect both versions; cross-check before you order.
Rotors on the Dana 30 are inexpensive ($55–80 in semi-metallic). Resurfacing an old rotor is rarely worth the labor cost. If the rotor has lip wear deeper than the thickness of a quarter, it's past minimum spec — replace it. Minimum thickness is stamped on the rotor hat; if you can't read it, measure with calipers and compare to the new rotor.
The caliper itself is a single-piston floating design. Sticking guide pins are the most common cause of uneven pad wear and pulling. When the caliper is off, slide the guide pins out and inspect: the rubber bushings should be supple, not cracked. The Raybestos H5004 kit replaces both pins and bushings for under $20 and prevents a return trip in six months.
If the caliper piston is seized, replace the caliper outright. A rebuild kit is cheaper, but a 40-year-old caliper body often has pitting that defeats a new seal. Loaded calipers from Centric or Raybestos run $60–100 each.
**Safety pillar applies here.** Test the pedal before the first drive. Pump until firm. Drive 50 feet, brake gently. Then drive 200 feet, brake harder. If the pedal feels spongy, you have air in the line — bleed before you leave the driveway.
| Part | Vendor | Est. price |
|---|---|---|
| Centric front brake rotor (1978.5-1986 CJ-7 Dana 30) | Centric / O'Reilly | ~$55 |
| Crown semi-metallic front pad set (1978-1981 two-bolt caliper) | Crown Automotive | ~$32 |
| Crown semi-metallic front pad set (1982-1986 with titanium dust shield) | Crown Automotive | ~$38 |
| Raybestos caliper guide pin and bushing kit | Raybestos | ~$18 |
| Brake fluid DOT 3 (32 oz) | Prestone / Valvoline | ~$8 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.