Scuff (roughen) the area that the patch will cover, so it will adhere tightly.

Apply the proper cement (adhesive), following the directions in the tire repair kit.

Remove the covering from the adhesive side of the patch and carefully place it on the inner liner.

Using a tool, called a sticher, roll it across the patch to bond the patch tightly to the inner liner.

A few basic safety rules for repairing a tubeless tire are as follows:

Do NOT attempt to repair a puncture by plugging the tire from the outside. ALWAYS dismount the tire and patch the inner liner.

Do NOT attempt to repair sidewalls or tires with punctures larger than a 1/2 inch.

Reduce the air pressure to at least 15-psi, when removing an object from the tire.

Broken strands in a steel belted tire can indicate more serious damage than initially suspected. Replace the tire.

Follow the procedures given in the tire repair kit.

TUBE REPAIR

If a tube tire has been punctured but has no other damage, it can be repaired with a patch. Remove the tube from the tire to find the leak. Inflate the tube and then submerge it in water. Bubbles will appear where there is a leak. Mark the spot. Then deflate and dry the tube.

There are two methods to patch a tube leak. They are the cold-patch method and the hot-patch method. With the cold-patch method (also known as chemical vulcanizing), first make sure the area is clean, dry, and free of grease and oil. Scuff the area around the leak. Then cover the area with vulcanizing cement. Let the cement dry until tacky. Press the patch into place. Roll it from the center out with a "stitching tool" or the edge of the patch kit can.

With the hot-patch method, prepare the tube in the same way as for the cold patch. Put the hot patch into place and clamp it. Then, with a match, light the fuel on the back of the patch. As the fuel burns, the heat vulcanizes the patch to the tube. After the patch has cooled, inflate the tube and recheck for leaks by submerging the tube in water. Another kind of hot patch uses a vulcanizing hot plate. The hot plate supplies the heat required to bond the patch to the tube.

PREVENTIVE MAINTENANCE

Preventive maintenance of tires and wheels involves periodic inspections, checking inflation pressure, wheel balancing, and rotation. Wheel bearings are periodically lubricated and checked for wear. These preventive maintenance steps will help assure vehicle safety and a longer component life.

Rotating Tires

Tire rotation can be beneficial in several ways. When done at the recommended times, it can preserve balanced handling and traction of the tires and even out tire wear. It can even provide performance advantages. Manufacturers recommend that tires be rotated every 3,000 to 5,000 miles, even if they do not show signs of wear. Tire rotation when done at the recommended times helps even out tire wear by allowing each tire to serve in as many of the wheel positions of the vehicle as possible.

NOTE

Remember that tire rotation can NOT correct problems due to worn mechanical parts or incorrect inflation pressures.

While every vehicle is equipped with four tires, usually tires on the front need to accomplish very different tasks than the rear tires. And the tasks encountered on a front-wheel drive vehicle are considerably different than those of a rear-wheel drive vehicle. Each wheel position can cause different wear rates and different types of tire wear. It is to your advantage when al! four tires wear together because as wear reduces tread depth of a tire, it allows tires to respond to the operator's input more quickly, maintains the handling, and it helps increase the cornering traction of a tire. Figure 8-41 shows common tire rotation diagrams. A description of each is as follows.

On front-wheel drive vehicles, rotate the tires in a forward cross pattern (A) or the alternative X pattern (B).

On rear-wheel drive vehicles, rotate the tires in a rearward cross pattern (C) or the alternative X pattern (B).

If the vehicle has directional tires, rotate these tires from front to back only and vise versa(D).

If the vehicle has nondirectional tires that are a different size from front to rear, rotate these tires from side to side only (E).