Lug nuts perform the task of keeping the rim firmly mounted to the brake rotor hub or brake drum. Sometimes lug nuts come off the vehicle stripped as a result of corrosion or cross-threading. On drum brakes, the lug nuts fasten to large studs, pressed in from the reverse side of the drum. If the lug nut strips, the stud threads will suffer the same damage and require replacement. Losing too many drum brake studs to damage without replacing them can result in a wheel that cannot rotate evenly under stress. A vehicle owner can replace a stripped stud without having to purchase a new drum.
Place the vehicle in park or neutral with the emergency brake set. Use a tire iron to loosen the lug nuts on the damaged wheel just enough to break them loose. Use a floor jack to lift the end of the vehicle frame that has the damaged stud. Place two jack stands under the frame. Use the tire iron to loosen the lug nuts completely, and remove the wheel from the vehicle. If a rear drum brake has the damaged stud, release the emergency brake.
Tap the drum with a hammer to shock it loose. Pull the drum off and set it down. Scrub the stud and stud shaft base with a wire brush and carburettor cleaner while on the hub. Use the wire brush and carburettor cleaner to scrub the stud flange and surrounding area on the inside of the hub. Take a hammer and tap firmly on the stud head.
Apply penetrating oil to both sides of the stud where it connects to the back of the hub and on the front side if the stud refuses to move with the hammer hits. Let the penetrating oil soak overnight. Reapply more penetrating oil during this period. Apply a large C-clamp around the hub. Place one clamp on the top of the stud end and the other end of clamp on the backside of the hub directly next to the stud flange.
Twist the C-clamp handle tight. Continue to twist the C-clamp handle until the stud breaks free and moves on its splines. If the stud still refuses to move, take a propane torch and heat the hub on both sides next to the stud. Do not heat the stud, only the hub. Quickly tap the stud end firmly with a hammer, or apply the C-clamp quickly and press it out.
Scrub the stud hole splines in the hub with carburettor cleaner and a wire brush. Wipe it clean with a rag. Apply lithium grease to the new stud and insert into the hub hole splines. Tape it with a hammer to get it started. Place about three or four washers over the stud end. Apply grease to the topmost stud. Use your fingers to twist a good lug nut over the new stud threads until flush with the spacer.
Use a tire iron to screw the lug nut down, forcing the stud to seat in its spline joint. Unscrew the lug nut with the tire iron and remove the spacers. Place the brake drum back on the hub. Set the wheel back on the brake drum and screw in the lug nuts by hand.
Tighten the lug nuts with a tire iron only enough to get them snug. Use the floor jack to lift the vehicle and remove the jack stands. Lower the vehicle and set the emergency brake. Tighten the lug nuts with a torque wrench according to manufacturer's specifications in your owner's repair manual.
If you have trouble removing the stud from the drum, take it to a machine shop to have it pressed out. They can also press the new stud in. Use all of the techniques described here before you opt for machine shop assistance.
Tips and warnings
- If you have trouble removing the stud from the drum, take it to a machine shop to have it pressed out. They can also press the new stud in. Use all of the techniques described here before you opt for machine shop assistance.