In a starter motor, the spiral engagement mechanism is referred to as the Bendix gear. When ignition is turned on, Bendix gear in the starter motor allows the pinion to engage with the flywheel on the engine. A fault in the Bendix gear can jam engagement between the pinion and the flywheel’s ring gear. The Bendix gear replacement is very easy and only requires simple tools like a screwdriver. However, you need to remove the starter motor to have access to the Bendix gear. Read on to find out how to replace Bendix gear in a starter motor to get the engine running smoothly.
Issues with the Bendix Gear
Several issues can occur with the Bendix gear, which can cause the engine to stop working properly. Following are some of the issues you can experience with the Bendix gear:
- The flywheel of the engine doesn’t engage with the starter motor.
- During mid-engagement, the pinion of the starter motor and the flywheel of the engine jams.
- The teeth of the Bendix gear inside the starter motor wear out or break.
- The bearing in the starter motor present behind the teeth of the Bendix gear fractures.
Types of Starter Motors
There are two types of starter motors:
- Inertia type starter
- Pre engaged type starter
Accessing and replacing the Bendix gear varies for both these types, which is why it is important to know what type of starter motor your car has. Check and replace the starter motor if it is damaged completely.
Cleaning the Bendix Gear
Sometimes debris or dirt gets stuck inside the Bendix gear, which causes it to malfunction. You can use petrol to clean the surface of the Bendix gear and get it functioning again. Make sure that the petrol is dried before putting the gear back in place, as its fumes can catch fire inside the motor. Oiling the gear is highly discouraged as it can attract more debris and dust particles, which can cause further hindrance.
If the cleaning process doesn’t solve the issue, then replacing the Bendix gear is the only option you are left with.
How to Replace Bendix Gear
You can easily replace the Bendix gear in your car in a matter of 20-25 minutes if you have a replacement available. But make sure you know the type of starter motor that you are dealing with.
For an Inertia Type Starter Motor
- Start by removing the starter motor from the car. Use a screwdriver to unscrew the screws holding the motor in place.
- Once the motor is removed, you have to dismantle the starter housing to access the Bendix gear.
- The Bendix gear is held in place by a circlip. In order to free the circlip, you have to compress the buffer spring. You can use a special compressing tool to achieve this task.
- As the spring is compressed, you can push the circlip out using a small screwdriver.
- Remove the compressing tool and slowly remove the gear off the shaft.
- Place the new Bendix gear in place.
- Using the compressing tool, pull the spring down, so you can reattach the circlip to hold the gear in place.
- Assemble the starter motor by placing the screws back in their place.
- You now have to start the ignition to test the starter motor.
For a Pre engaged Starter Motor
- Dismantle the starter motor to remove the clutch and pinion off the motor.
- If the clutch and pinion are damaged, they can also be replaced as a single unit.
- Now, remove the thrust collar in the vice of the motor by gripping the armature. If the collar is held in place by a jump ring, remove the ring first with a screwdriver. You can also use a pulling tool to free the collar without damaging anything.
- Remove the stop bracket that holds the clutch in place. Keep it safe, as you will have to place it back once the replacement is made.
- You can now lift off the entire pinion clutch assembly.
- Now, Replace the clutch and pinion assembly, the thrust collar, and the jump ring on the starter motor. Using a puller, place the thrust collar on the jumping ring.
- Now, measure the end float of the armature to see if the collar is far enough. The end float movement should be somewhere around 3mm lengthways.
- Once done, you need to reassemble the starter motor and secure it into place.
- You now have to turn the ignition on to see if the replacement has been successful.
Test the Starter Circuit
Mechanical issues aside, you need to make sure that your starter circuit is functioning properly too. Once you have replaced the Bendix gear, check the starter circuit to rule out any electrical problems in the starting process. You can use a multimeter or a simple test circuit for this purpose. Also, make sure that your car’s battery is fully charged; otherwise, you can buy a new battery.
Other Issues
If the car continues experiencing starting issues, you might want to inspect the ignition system thoroughly. Bad fuses need to be checked and replaced immediately. Changing the old spark plugs with good quality spark plugs can significantly improve your car’s engine performance.
Sometimes the electrical components aren’t the main issue, but the problem lies within the wiring system. Start by checking the connections and leads of the battery. Then check the high-tension circuit of the ignition. If the leads are damaged, buy and fit new high-tension leads in the ignition system to improve your car’s response time.
Regular maintenance of your car’s ignition system can save you tons of money that you will have to spend in case a major component malfunctions in the system. Sometimes small mechanical faults can cripple the whole system, which is why it is best to know how to check and test your car thoroughly.
Knowing how to replace Bendix gear is extremely simple once you know what exactly needs to be done. Easy tasks like these are not very time-consuming and can help you improve your car’s functionality without any professional assistance.
