Meritor provides the following procedure for installing hubs with three drum-and-wheel pilots:
* Park the vehicle on a level surface and block the wheels to prevent the vehicle from moving. Raise the vehicle frame so that the tires are off the ground and support the vehicle with safety stands.
* Use a scraper or wire brush to clean the hub mounting surfaces (flange and pilots).
* The three pilots of the lightweight hub are located 120 degrees apart. Rotate the hub so that one of the hub pilots is at the TOP center or 12 o’clock position. (See Figure 1.)
* Mount the brake drum so that it is seated on the drum pilot at 12 o’clock and against the flange at the hub. The shorter hub pilot for the drum is approximately ¼ in. long and is slightly larger in diameter than the pilot for the wheel.
* Ensure the drum is fully seated against the flange and remains there while the wheels are mounted. (See Figure 2.)
* Ensure that the wheel matches the hub mounting system and a hub is located at the TOP position.
* Install the wheel onto the pilots taking care that the wheel does not impact the drum before the wheel is fully seated. If the wheel impacts the drum before the wheel is fully seated, make sure drum us still on the pilot.
* Check that the wheel and rim assembly does not interfere with the brake drum.
* Verify that the valve stem does not touch the brake drum.
* Tighten the wheel nuts in a star pattern in 50 lb-ft increments until 400 to 500 lb-ft is reached. (See Figure 3.)
* Rotate the wheels to verify that there is a straight tire/wheel line and that there is no rubbing of the brake drum on the shoes.