Brake pads disintegration

[DLT]

Just inspected front pads, late model sliding caliper, to find that the outer pad both sides of van has completely disintegrated down to the back plate,  while the inner pads still have plenty left, is this common, or an indication of a problem with the calipers? Already ordered new discs and pads. 

[TONYT25T25]

Sounds like one part of the caliper is not retracting, I would have a good look at its operation, clean and lubricate if required.  Maybe worth posting a couple of images. Just to add was there a noticeable drop in fluid at the reservoir.

[maxstu]

Yep. Agree with above. A classic sign of a jammed caliper not retracting caused by a combination of dust, rust and wear.
Give it a clean.

[DLT]

Sounds like one part of the caliper is not retracting, I would have a good look at its operation, clean and lubricate if required.  Maybe worth posting a couple of images. Just to add was there a noticeable drop in fluid at the reservoir.

No drop in fluid, will check over calipers. Already seen no leaks on either when dismantling.