HZJ / Large Case Denso OSGR Starter Contacts Kit - 28226-HZJ-Kit

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HZJ / Small Case Denso OSGR Starter Contacts Kit

This is a basic starter contacts replacement kit for Toyota large case OSGR (off-set gear reduction) starter motors as commonly found in many different models of diesel powered Toyota vehicles with starter outputs from ranging from 2.4kW to 4.5kW.

The kit is made up from the battery terminal kit 28226-54320, and the motor terminal kit 28226-54220.

It is a good idea to also check your starter solenoid plunger (28235-17030), the plunger return spring (28165-77090), and the small ball bearing (90099-12009) located in the solenoid assembly (required parts). Sometimes when the return spring has been over-heated, it is no longer 'springy' and becomes too short.

It is worth noting that there are a few different styles of starter plungers. And, there are several variations of the starter contacts in size and configuration. Please compare your details to what is pictured in the product photos.

This kit is not compatible with small case / petrol (and light duty diesel) Denso OSGR starter motors. Use 28226-FZJ-Kit instead

Repair Procedures:
Starter Motor Solenoid / Magnet Switch Repair procedures from the Toyota Service Manual (1988)

Part number:
28226-HZJ-Kit

Kit Contents:
28226-54320 + 28226-54220
Toyota (Denso) - Japan

Important Notes:

It's very uncommon that these starters fail outright - unless - the solenoid contacts lock on and the starter more is driven to over-speed by the engine which can cause the starter motor to fly apart.

The most common cause of the solenoid staying engaged is worn out starter solenoid contacts and plunger. Wear allows the plunger to spot weld itself to the contacts, and this is caused by misalignment (from this wear) and the ensuing arcing due to the high current draw.

Do your starter maintenance on a regular schedule:

Starter contacts and the solenoid plunger in this type of starter motor should be considered a maintenance item, and the plunger and contacts maintenance should be performed at a regular interval. I'd suggest that this is performed roughly every 100,000 Kms with your timing belt and water pump maintenance, and maybe up to 200,000 Kms depending on how many times the starter is engaged (ie: city driven vs highway driven, where a highway driven vehicle is started far less frequently).

** The key point is to not let this maintenance go unattended or you will eventually have problems **

The first signs of real problems showing up is usually a situation where you turn the ignition key to start the engine and all you get is a 'click' from the solenoid - which is not always audible - followed by no cranking taking place. Sometimes rotating the key back and forth into and out of the cranking position will get the starter to eventually work.

Less frequetly you will not get any advanced warning and your starter motor will engage, and then not disengage. If you are unable to shut down the engine and immediately disconnect the batteries, your starter will either burn itself out or it will over-speed and self destruct. Turning off the does not mean that the starter will stop running.

...So, it should be carefully noted, that replacing the contacts and plunger from time to time is far less costly than being stranded and having to replace a very expensive starter motor.

Most of the time all these heavy duty diesel starters motors need is the contact kit for the solenoid and the solenoid plunger, and optionally the plunger return spring and the small ball bearing that goes into the bottom of the hole where the spring lives.

Denso OSGR starter motor:

This design of starter motor is called an off set gear reduction starter (OSGR) - this design is very common in diesel engines due to its excellent record of reliability, along with its high torque and rotational speed. These starter motors can also be found in larger and smaller formats in gasoline engines, and are used by many different manufacturers for larger diesel engines - such as John Deere and Dodge/Cummins.

2024 02 29
8708.29
2822654320
2822654220