rear drum brakes issue
Since the brake assembly is a 2.5" set up there are a couple of possibilities. Since the 10x2.5" drums fit I'm assuming the axles are BBP, 5x4.5"
One possibility is that the aftermarket axles have the original SBP A-body axle flange offset, which is different from the BBP axle flange offset used by every other Mopar. If that's the case, you would need the 10x1.75" SBP A-body brakes with the drums re-drilled for the BBP. Moser still sells brand new A-body axles that have the original SBP axle flange offset, but with the larger bolt pattern, for use with the 10x1.75" set up and re-drilled drums. Totally dumb IMO, but they're out there.
The other is that you actually have BBP axles with the correct offset, but have the wrong backing plates for the 10x2.5" brakes.
To measure the backing plate offset you want to set the backing plate flat on a bench. You'll need to hang the bottom 1/3 of the backing plate off the edge of the bench so that the mounts for the e-brake cables don't keep the backing plate from sitting flat. It isn't much, but they do change the measurement. Then, measure from the bench to the top of the backing plate through the center hole (for the axle) in the backing plate. Since your axle and brakes are all assembled, you might be able to accomplish that measurement using a straight edge across the backside of the backing plate and measuring back into the backing plate where it mounts. The measurement will be smaller, you'll have to add the thickness of the backing plate to match the measurements below.
If you get ~1.75", you have 10x2.5" plates. If you get ~1.25", you have 10x1.75" plates.
Since the brake assembly is a 2.5" set up there are a couple of possibilities. Since the 10x2.5" drums fit I'm assuming the axles are BBP, 5x4.5"
One possibility is that the aftermarket axles have the original SBP A-body axle flange offset, which is different from the BBP axle flange offset used by every other Mopar. If that's the case, you would need the 10x1.75" SBP A-body brakes with the drums re-drilled for the BBP. Moser still sells brand new A-body axles that have the original SBP axle flange offset, but with the larger bolt pattern, for use with the 10x1.75" set up and re-drilled drums. Totally dumb IMO, but they're out there.
The other is that you actually have BBP axles with the correct offset, but have the wrong backing plates for the 10x2.5" brakes.
To measure the backing plate offset you want to set the backing plate flat on a bench. You'll need to hang the bottom 1/3 of the backing plate off the edge of the bench so that the mounts for the e-brake cables don't keep the backing plate from sitting flat. It isn't much, but they do change the measurement. Then, measure from the bench to the top of the backing plate through the center hole (for the axle) in the backing plate. Since your axle and brakes are all assembled, you might be able to accomplish that measurement using a straight edge across the backside of the backing plate and measuring back into the backing plate where it mounts. The measurement will be smaller, you'll have to add the thickness of the backing plate to match the measurements below.
If you get ~1.75", you have 10x2.5" plates. If you get ~1.25", you have 10x1.75" plates.
