Tubeless Tire Repair

Some tires are tubeless. Instead of being sealed in an inner tube, the air in these tires is sealed in a space between the outer casing and the rim. Both this space and the point of contact of the tire against the rim must be airtight. The rim, on which the valve for inflating the tire is mounted, becomes a part of the air-retaining chamber. Do not tear or otherwise injure the sealing ribs.

Before replacing a tubeless tire, examine the rim carefully for dents, roughness, and rust; any defects may impair or break the air seal. Straighten out any dent with a hammer, and use steel wool or a wire brush to clean the bead seat area of any rust or grit. After cleaning, paint any bare metal spots where the tire bead seats to make it easier to remove the tire later. If the rim is badly damaged, replace it with a new one.

The procedure for repairing a tubeless tire is accomplished by the following steps:

1. Inspect the inside of the tire and remove nails or other damaging items. Then scrape the damaged area with a sharp-edged tool and buff (fig. 3-33, step 1). Be careful not to damage the liner or expose any cords.

NOTE: Serious injury can result using your bare hand to free for obstructions, use a rag to feel inside the tire.

2. Lubricate the hole by pushing bonding compound into the hole from both sides of the tire (fig. 3-33, step 2). Also, pour bonding compound on the insertion tool and push it through the hole with a twisting motion until it can be inserted and withdrawn easily.

3. Using a plug slightly larger than the hole, place it in the eye of the hole of the insertion tool. Wet the plug with bonding compound. Always pour it directly from the can so the contents in the can does not become contaminated, as shown in figure 3-33, step 3.

4. While stretching and holding the plug with your hand, insert the plug into the hole from the inside of the tire. Stretch and hold the plug until it is forced into the hole and one end extends through it, as shown in figure 3-33, step 4.

5. After the plug extends through the tire, remove the insertion tool and cut off the plug approximately 1/16 inch above the surface (fig. 3-33, step 5).

6. When using a cold patch, carefully remove the backing from the patch and center the base of the patch on the damaged area. Stitch the patch down firmly with the stitching tool working from the center out (fig. 3-33, step 6).

7. When using a vulcanizing hot patch, cover the area with a light coat of glue and allow it to dry. This glue normally comes with the hot patch kit. Remove the backing from the patch and center it on the damaged area. Clamp it finger tight, apply heat, allow to cure, and then cool. (fig. 3-33, step 7).

NOTE: Each patch or plug kit should contain specific instructions.

Figure 3-33.-Repair of tire punctures

Punctured tires can be repaired without being removed from the rim. In this case, the insertion of the plug is performed from the outside in, and steps 6 and 7 of figure 3-33 are not required.

NOTE: For radial-ply tires, repairs can only be made in the central tread area between the major grooves.

The procedures for removing and remounting a tubeless tire are similar to that for tube tires. If the seal is broken or defective, use a tube inside the tire; otherwise, the tire will lose air, and you will have to inflate it frequently. Some tubeless passenger car tires must be removed from the backside of the rim to prevent stretching the bead wires too far and causing them to break. If in doubt about any detail of the procedure for changing tubeless tires, follow the tire manufacturer's instruction or consult the maintenance supervisor.