Contents: Porosity of cast wheels ↧ Restoration of protective coating of… ↧ Damage to the alloy on the wheel… ↧ Clear coat damage on unpainted wheels ↧ Coating application procedure ↧ Balancing with removal from the… ↧ Correction of tire imbalance ↧ Wheel and tire selection and… ↧ Mounting and dismounting of tires ↧
Porosity of cast wheels
Repairs to discs that involve welding, heating or forging are not permitted.
1. Raise the vehicle and place it on the supports provided for this purpose.
2. Remove the tire and wheel assembly. See the section in this section "Wheel".
Warning! To avoid serious injury, do not stand near the tire while inflating it, as the tire bead may burst if it bounces sharply over the annular projection (hump). Do not allow the tire pressure in any size to increase to more than 275 kPa (40 psi), until the tire beads are in place. If at a pressure of 275 kPa (40 psi) the tire beads do not fit into place, release the air from the tire. Lubricate the tire beads. Re-inflate the tire. Excessive air pressure in the tire can cause the bead to burst and cause an accident.
3. The location of leaks can be determined by inflating the tire to a pressure of 345 kPa (50 psi) and lowering the tire and wheel assembly into the water.
4. Mark the leak locations and remove the tire from the wheel.
5. Sand the inside of the wheel at the leak location with 80 grit sandpaper. Clean the leak location with a common cleaner.
6. Apply a 3.3mm thick layer of adhesive/sealant to the leak area (0.13 inches). Leave for 12 hours to dry.
7. Install the tire on the wheel. Inflate the tire to a pressure of 345 kPa (50 psi) and check for leaks according to step 3.
8. Adjust the tire pressure according to the specifications. See the section in this section "Tire Size and Air Pressure".
9. Balance the tire and wheel assembly. See the section in this section "Wheel and Tire Balancing".
10. Install the tire and wheel assembly. See the section in this section "Wheel".
11. Lower the car.
Restoration of protective coating of light alloy wheels
A clear or coloured protective coating is applied to the surface of alloy wheels by the manufacturer. If this clear coating is damaged or removed, the physical properties of the surface may begin to deteriorate. This can happen in some automatic car washes that use brushes with silicon carbide-tipped bristles to clean white surfaces and tyres. Once the protective coating has been damaged, further deterioration will occur due to exposure to caustic detergents and road salt. Here is how to remove dirt, clean and restore the coating on alloy wheels.
Before repairing damage to the alloy or clear coat, it is necessary to prepare the wheels and tires.
1. Remove the wheel from the car.
2. Mark the position of the weights located on the outside and remove them.
3. Wash the wheel inside and out with water-based all-purpose cleaner. Remove grease and oil with solvent.
4. Protect the tire before applying the coating.
5. Using 400-grit wet or dry sandpaper, sand the painted areas that do not require refinishing. Sanding will improve the adhesion of the clear coat.
Damage to the alloy on the wheel surfaces
1. Place the wheel on the brake turning machine and turn it slowly.
2. Sand the wheel using a sanding pad. Hold the pad parallel to the wheel surface and work slowly back and forth from the center to the outside edge of the tire, removing any damage. Use the specified grit sandpaper in the following order:
- grain size 80.
- grain size 150.
- grain size 240.
Clear coat damage on unpainted wheels
1. Apply the chemical cleaner. Use a small 1/4 inch (6.5 mm) brush to apply the cleaner to the perimeter, around the spokes, and similar areas.
2. Remove the cleaning agent according to the manufacturer's instructions.
Caution: To avoid serious injury, do not use the motor to rotate the wheel while grinding.
3. Using 240 grit sandpaper, sand the wheel by slowly rotating it on a brake resurfacing machine or by mounting it on the car and rotating it by hand. Sanding restores the appearance of the machined surface and improves adhesion.
4. After repairing the metal surface or clear coat, the wheels must be recoated.
Coating application procedure
Warning! To avoid serious injury when applying any two-component paint coatings, follow the manufacturer's recommended precautions. Failure to follow these recommendations may cause lung irritation and allergic reactions in the respiratory system.
1. Clean the surface.
2. Wet the wheel with chemical cleaner for 1 - 3 minutes. Rinse the wheel with water and dry.
3. Wet the wheel with the chemical compound to obtain a coating for 1 - 3 minutes. Rinse the wheel with water and dry.
4. Apply Urethane Additive urethane coating following the 3 steps below.
1st layer - apply a thin layer by spraying with a thin aerosol and dry.
2nd coat - spray or brush on a thin layer and let dry.
3rd coat - spray or brush on a thick, double wet coat and let dry.
5. Allow the urethane coating to dry for 24 hours or flash dry for 30 minutes and then cure for 30 minutes at 60°C (140°F). Allow the urethane coating to cool for 5 minutes before installing the wheel on the vehicle.
5. Allow the urethane coating to dry for 24 hours or flash dry for 30 minutes and then cure for 30 minutes at 60°C (140°F). Allow the urethane coating to cool for 5 minutes before installing the wheel on the vehicle.
Balancing with removal from the vehicle
Perform wheel balancing using an electronic stand for balancing wheels dismounted from the vehicle. The balancing stand is easy to operate and provides both static and dynamic balancing. Unlike balancing carried out on the vehicle, when balancing with dismounting from the vehicle, the imbalance of the brake drum or disc is not corrected. This disadvantage is compensated by the accuracy (usually within 3.54 grams (0.125 oz)). Secure the wheel to the stand using a cone inserted into the center hole on the inside of the wheel; do not use the wheel bolt holes for this purpose.
Correction of tire imbalance
There are two methods for correcting pre-balanced tires that continue to vibrate. The first method is to use an automatic treadmill that loads the tire and grinds away small amounts of rubber from the high points on the two outer tread grooves. The correction made by this method is usually permanent and, if done correctly, does not significantly affect the appearance or life of the tire. Treadmilling of tires with knives is not recommended because of the significant reduction in tread life and the frequent need for re-treading.
The second method involves removing the tire and installing it on the rim after rotating it 180 degrees. This method should only be used on tires and wheels that are known to cause vibration, as using it on balanced assemblies will likely result in vibration as well.
Wheel and tire selection and installation
The selection and installation of tires and wheels is performed at the assembly plant. The selection and installation ensures the alignment of the most rigid part of the tire in the radial direction (or a protruding point), with that part of the wheel whose radius is smallest (or in which there is a depression).
The protruding point of the tire is marked by the manufacturer with red paint or indicated on a label attached to the outer sidewall.
The wheel depression will be located where the valve is located.
Before removing the tire from the wheel, mark the location of the valve on the tire to ensure subsequent installation in the same position.
New tires of the same quality as those installed at the assembly plant will also have the ridge and valley marks made in a similar manner.
Mounting and dismounting of tires
Note: Use a tire changer to mount and demount tires. Follow the equipment manufacturer's instructions. Do not use hand tools or tire levers to change tires. These tools may damage the tire beads or wheel rim.
1. Clean the rim seat with a wire brush or coarse steel wool to remove grease, old rubber, or light rust. Lubricate the tire bead with tire lubricant before mounting or demounting the tire.
Warning! To avoid serious injury, do not stand near the tire while inflating it, as the tire bead may burst if it bounces sharply over the annular projection (hump). Do not allow the tire pressure in any size to increase to more than 275 kPa (40 psi), until the tire beads are in place. If at 275 kPa pressure (40 psi) if the tire beads do not fit into place, release the air from the tire. Reapply lubricant to the bead and inflate the tire. Excessive air pressure in the tire may cause the bead to burst and cause an accident.
2. After mounting the tire, inflate it until the beads are in place. Never use a pressure increase higher than 275 kPa (40 psi) so that the sides fall into place.
3. Install the valve and inflate the tire to the required pressure. Make sure that the mounting ring that runs along the sides of the tire is positioned around the edge of the rim and is visible from both sides of the wheel. This position of the tire ensures that the tire rim is installed in its proper place.
(Information taken from the official website: «CHEVYMAN.RU»)