I've discovered that the recently released Astro 78825HD kit works perfectly for servicing the E46 M3 rear wheel bearing and hub. For the purposes of this task, it's functionally equivalent to the $500+ CTA 8650 or Sir Tools B90 kits, but at a fraction of the cost.
Getting the sizing right for the press components is harder than it sounds. The E46 M3 uses a large, double-row rear wheel bearing, and both the inner and outer race dimensions matter when choosing drivers and receiver cups. The outer race measures 85mm OD and 82mm ID, while the inner race measures 61mm OD and 45mm ID. The hub flange is about 100mm OD. Most generic press kits list adapter diameters without clarifying whether they refer to inner or outer dimensions, or which bearing surface they’re meant to contact. Because each step of the job requires the press load to be carried only through one race at a time, even a few millimeters of mismatch can cause point loading or damage. After measuring and testing combinations, I matched the Astro 78825HD pieces that contact only the correct race faces and clear the trailing arm properly.
1. Bearing Removal
Use Astro #11 (2.48"/63mm OD) as the pusher (driver) on bearing inner face.
Use #15 receiver cup (4.00"/101.6mm OD), supported by the #002 press plate. The #15 receiver cup is the right size to sit on the ~100 mm hub flange and fully support the trailing arm housing without contacting the machined bearing bore.
Here is the hub flange with the bearing removed.
2. Bearing Installation
When pressing in the new bearing, use the #02 press plate (3.27"/83mm OD) to apply force to the outer race and the #01 thrust bearing assembly (3.48"/88.3mm) on the nut side of the spindle.
The #02 plate is correctly sized—larger than the bearing’s inner bore (82mm) but smaller than its outer race (85mm)—so it contacts the outer race face evenly without binding in the trailing-arm bore.
Press slowly until the bearing seats fully against the shoulder inside the trailing arm, then install the snap ring.
3. Hub Installation
The hub is pressed inward from the outside of the trailing arm. The spindle passes through from the inner side of the arm and threads into the hub.
On the inner side of the bearing, place #11 (2.48"/63mm OD) against the inner race. It acts as a support plate, ensuring all press load is transmitted through the inner race only.
On the outer side, use the #02 thrust bearing assembly (3.48"/88.3mm OD) under the press nut to pull the hub inward through the bearing.
#11’s 63mm diameter perfectly matches the 61mm inner race shoulder—large enough for full, even contact, small enough to avoid touching the outer race—preventing point-loading and any brinelling of the races or balls.
Tighten slowly while ensuring the spindle and hub remain square to the arm. The hub will seat firmly against the inner race.
Getting the sizing right for the press components is harder than it sounds. The E46 M3 uses a large, double-row rear wheel bearing, and both the inner and outer race dimensions matter when choosing drivers and receiver cups. The outer race measures 85mm OD and 82mm ID, while the inner race measures 61mm OD and 45mm ID. The hub flange is about 100mm OD. Most generic press kits list adapter diameters without clarifying whether they refer to inner or outer dimensions, or which bearing surface they’re meant to contact. Because each step of the job requires the press load to be carried only through one race at a time, even a few millimeters of mismatch can cause point loading or damage. After measuring and testing combinations, I matched the Astro 78825HD pieces that contact only the correct race faces and clear the trailing arm properly.
1. Bearing Removal
Use Astro #11 (2.48"/63mm OD) as the pusher (driver) on bearing inner face.
Use #15 receiver cup (4.00"/101.6mm OD), supported by the #002 press plate. The #15 receiver cup is the right size to sit on the ~100 mm hub flange and fully support the trailing arm housing without contacting the machined bearing bore.
Here is the hub flange with the bearing removed.
2. Bearing Installation
When pressing in the new bearing, use the #02 press plate (3.27"/83mm OD) to apply force to the outer race and the #01 thrust bearing assembly (3.48"/88.3mm) on the nut side of the spindle.
The #02 plate is correctly sized—larger than the bearing’s inner bore (82mm) but smaller than its outer race (85mm)—so it contacts the outer race face evenly without binding in the trailing-arm bore.
Press slowly until the bearing seats fully against the shoulder inside the trailing arm, then install the snap ring.
3. Hub Installation
The hub is pressed inward from the outside of the trailing arm. The spindle passes through from the inner side of the arm and threads into the hub.
On the inner side of the bearing, place #11 (2.48"/63mm OD) against the inner race. It acts as a support plate, ensuring all press load is transmitted through the inner race only.
On the outer side, use the #02 thrust bearing assembly (3.48"/88.3mm OD) under the press nut to pull the hub inward through the bearing.
#11’s 63mm diameter perfectly matches the 61mm inner race shoulder—large enough for full, even contact, small enough to avoid touching the outer race—preventing point-loading and any brinelling of the races or balls.
Tighten slowly while ensuring the spindle and hub remain square to the arm. The hub will seat firmly against the inner race.
Attached Files
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