Moderator: John Brennan
XR and non-ABS/non-4 wheel disc Sierra use the same "Smaller bearings"
Scorpio and 2wd Cosworth use the same Front and Rear bearings
The standard Sierra with 4 wheel Disc and ABS I know use the same as the Scorpio/Cossie rear, but not sure about the front. Later XR front hubs had all the casting for ABS configuration, so I'm guessing no, but can't confirm.
4x4 use the same size on all 4 corners as the Scorpio/Sierra Disc rear
Doesn't seem to be a lot of real definitive P/N, so here's the result of my research:
Bearings Front and Rear 35mm ID/60mm OD: Set24, A31, 051-3598
Seals 50mm ID/65mm OD: 3743
Scorpio/2wd Cosworth/Sierra Disc Brake (rear only confirmed):
Bearings Front 38mm ID/63mm OD: Set11 / FW139 / A18 / 051-4082
Bearings Rear 40mm ID/68mm OD: Set721 / FW141 / 051-4052
Seals Front 53mm ID/68mm OD: 4990
Seals Rear 55mm ID/70mm OD: 3723
Of note: RockAuto seems to have done a good job of weeding out the incorrect numbers between the XR and Scorpio.