Convert Front Drums to Disc

Donor cars: 1969–72 A-body (Chevelle/Malibu/Monte Carlo, Cutlass/442, Skylark/GS, Tempest/LeMans/GTO/Grand Prix, F-85), 1968–74 X-body (Nova, Apollo, Ventura/GTO, Omega), or a 1969 F-body. Avoid 1973+ A-body and 1975+ X-body (redesigned spindle won’t fit) and big B-bodies/Cadillacs (spindles too tall, wrong bolt circle). Earlier cars have the pricier, rust-prone 4-piston caliper; first-gens use the “early” GM single-piston corporate caliper.

What to gather:

• From the donor: spindles, calipers (fine as cores for rebuilds), caliper brackets, rotors, master cylinder, booster (if you want power), combination/proportioning valve, and dust shields/backing plates. All but the spindles, caliper brackets, and dust shields can serve as cores. (New spindles, brackets, and shields are available from Classic Industries/NPD if needed.)
• Keep from your car: the F-body steering arms — first-gen F-bodies (and X-bodies) are rear-steer, so bolt your own drum-brake steering arms onto the donor spindles (keep left/right straight).
• Buy new: brake pads (Hawk/EBC/Performance Friction); new front flex hoses (never reuse old ones — but take the old ones along to match the ends); DOT 3 fluid (Ford HD DOT 3 is well regarded; avoid silicone); Timken inner/outer bearings, races, and seals; high-temp grease; new rotors (the originals are often unusable).

Booster & pedal rod: the booster is the same except for pushrod length — compare the new booster to the one on your car (the pedal-to-booster pushrod can differ ~1″), and use the correct long/short pin for your master/booster combo. A-car boosters reportedly have an “A” stamped on the firewall pushrod. A high-volume “fat boy” master (1967 Vette / 1967–68 Z28 / J52/J56) is a nice upgrade over the standard 1969 disc master.

Control arms: you do not need to change them — just take the spindle and everything attached to it (dust shield, caliper bolts, etc.). Remove the upper and lower ball joints and take everything in between.

Wheels: some 14″ wheels rub the single-piston caliper (a 14×7 Rally II clears); all 15″ clear. Disc brakes push the track out ~1/4″, so very wide/deep wheels may get tight. (Admin note: Rally II rim code “JC” was used on both disc- and drum-equipped 1968 Firebirds.)

Fitment gotchas (from a member’s detailed 1968 build with 1969 donor parts): control arms weren’t needed (swapped only as a bonus); the 1969 flex-line brackets weren’t a direct bolt-on to the 1968 subframe (locating them took guesswork); rear axle hard lines needed minor rebending for the 8.5″ 2nd-gen housing; a couple of fittings didn’t match the prop-valve ports and needed adapters or a shop-made line; and stainless lines are harder to bend/flare than mild steel. El Camino 1-piece rotors are a good direct replacement for the too-thin 2-piece originals.

For comparison, complete kits: Firebird/Camaro Specialties sold a new-component front disc kit for ~$795 (likely mild-steel lines, rubber flex lines) or a used-parts kit for ~$350 — a kit means less fabrication. This build came in ~$195 over the $795 kit but with better parts. Other budget references: pieced junkyard parts ~$100; salvage wheel assemblies + proportioning valve ~$150–250; one member’s complete 1968 swap (junkyard spindles/brackets/shields + new rotors, bearings, hoses, rebuilt calipers/booster/master) ~$500. (Prices ~1999.) Skip the ~$825 bolt-on kits if you have salvage yards.

Upgrades & staying drum: DOT-approved braided steel lines give a firm pedal. Drums aren’t terrible for a single stop but fade quickly with repeated hard stops (hills, traffic); if staying drum, Praise Dyno (praisedynobrake.com) makes good drum upgrades.