Deteriorating Leather - Not a candidate for restoration, Here's why 

You're welcome.

you can, however the dominant strength in leather is in the epidermal (outer) layer, so the more you sand the more you are compromising the leather's integrity. The deeper you go into a hide, the less mature the fiber structure. The other variable is how the leather was tanned. Poor tanning means weak leather to start with, state of the art tanning will provide durability.

@@KevinGillan Thanks for the info. Will gluing a thinner piece of leather to the backside act to stabilize the leather from pulling apart? Have you ever repurposed an old piece of leather for a project? I have a 50 year old large leather US Postal mail bag that I want to cut down and restitch to make a much smaller size bag.

The key to successfully repairing or restoring leather is a function of the basic integrity of the leather's fiber structure. If the leather shows deep cracks or fissures or the epidermal layer is compromised, that is, fails the tape test as shown in this video, then any repair or restoration will last only as long as the surrounding leather lasts. If the leather is at the end of its useful life, then there is no magic solution that will correct that. You can conceal it, but you can't say its like new as it won't behave like new. Anyone who claims otherwise is just plain wrong.