How to Repair a Car Alternator Along with Signs of Its Damage

How to repair a car alternator is something that can make it easier for you to handle problems with your car's alternator. The alternator itself is a component that functions to generate the flow of electrical current in the car's engine.

If this component is damaged, the electrical flow in the engine will not occur. We will share how to repair a car alternator in this article. However, before that, we will provide information about the signs of a damaged car alternator.

Signs of a Damaged Car Alternator

When the car alternator starts to fail, it will show several signs. There are about five signs that indicate a damaged car alternator. These five signs are:

Car Headlights Dimming

This first sign will appear when you drive at night. The headlights usually start to dim due to insufficient electrical supply from the alternator to the car's engine.

Unusual Noises

If your car makes noise while driving, you need to be cautious. This could be a sign of a failing car alternator. If the noise starts to be heard, try checking your car's alternator immediately. This sign commonly appears due to damaged bearings in the alternator. Alternatively, it could also be due to a broken diode rectifier in the alternator.

Car Won't Start Even After Replacing the Battery

Often, the car is very difficult to start, even if you have replaced the battery. If this happens, it is a sign of a damaged car alternator. This sign appears due to insufficient output power generated by the alternator.

Indicator Light on the Car is On

One of the lights that indicate a problem with the car is the indicator light. This light will turn on if the car has a problem, one of which is a damaged car alternator. If this happens, usually the alternator is damaged and cannot supply electricity to the engine.

Overcharging of the Car Battery

This is a sign of quite severe damage to the car alternator. This sign appears when the alternator's output reaches 15 volts, causing the battery fluid to boil. If left unchecked, the headlights will shine very brightly, especially when the car is accelerated at high RPM.

How to Repair a Car Alternator

After knowing the signs of a damaged car alternator, let's move on to how to repair the car alternator. The method of repairing the car alternator consists of several steps, namely:

Check the Alternator Bearings

This is the first step that must be taken. To check the alternator, you only need to use a dynamo tester on the alternator pulley. 

Inside the alternator bearing, there is a component called the bearing housing. Check this component carefully. If there are any broken or cracked parts, replace them with new components.

Disassemble and Clean All Parts of the Alternator

After successfully checking the bearings, you need to disassemble all parts of the alternator. Open it carefully to avoid causing damage. This method also applies to the bearings that have been checked previously.

After that, clean all parts of the alternator. Once done, you can proceed to the next step.

Measure the Parts of the Alternator

Measuring the disassembled parts of the alternator is quite important. This is to ensure whether the sizes of these parts remain the same or have decreased. If they have decreased, those parts need to be replaced with new ones.

The parts that need to be measured are:

• Alternator brushes (minimum size 4 mm).
• Alternator rotor ring (must have a minimum diameter of 12.5 mm). If defects are found in this part, you can immediately machine it. Besides diameter, this part must also have a resistance size of 1.5 to 4 ohms.
• Stator windings (must have a minimum resistance size of 20 ohms).

Reassemble the Bearings and All Parts of the Alternator

After measuring the parts of the alternator, reassemble all those parts along with the bearing components. Do not immediately install the bearings and all parts of the alternator into the car. First, test it using a dynamo tester. If it functions well, you can install it into your car.

That is how to repair a car alternator, as well as the signs of damage to the alternator itself. Hopefully, this can help you, especially those who are experiencing problems with their car alternator.