Changing from 8.25 to 8.75
You can't use BBP brakes on re-drilled SBP axles. SBP axles have a different flange offset than BBP axles do. If you re-drill SBP axles for the 5x4.5" pattern you have to re-drill SBP brakes.
However, backing plates for a BBP 8.25 are the same for an 8 3/4 with BBP axles (not re-drilled!). The only difference is that some the 8.25" housings only had 4 bolts to mount the backing plates, vs. 5 bolts for the 8 3/4 housings. But if you drill the 5th hole the backing plates bolt right on, the other 4 have the same pattern. BBP brakes all use the same axle flange offset and can be swapped between the later 7.25" BBP axles, the 8.25, 8 3/4 and Dana, with the only issue being the 4 mounting holes vs. 5.
You can't use BBP brakes on re-drilled SBP axles. SBP axles have a different flange offset than BBP axles do. If you re-drill SBP axles for the 5x4.5" pattern you have to re-drill SBP brakes.
However, backing plates for a BBP 8.25 are the same for an 8 3/4 with BBP axles (not re-drilled!). The only difference is that some the 8.25" housings only had 4 bolts to mount the backing plates, vs. 5 bolts for the 8 3/4 housings. But if you drill the 5th hole the backing plates bolt right on, the other 4 have the same pattern. BBP brakes all use the same axle flange offset and can be swapped between the later 7.25" BBP axles, the 8.25, 8 3/4 and Dana, with the only issue being the 4 mounting holes vs. 5.
