I am afraid I dont understand. Shoes came from the store with lining just to be installed. If there is a way to change the arc of them I am not aware of it.
Arcing brake shoes is the matching of the brake shoes to the drum.
They will naturally do it themselves, but it used to be that the proper way (I guess that is a relative term) was to put them on a machine and custom fit them.
http://model-a-wis.com/brakearc.pdf
I doubt many folks do it now.
That said, one of the first things I do, when purchasing new brakes drums etc is flip them over on the parts counter and make sure they "fit" ie, and I don't know if you have the old parts or not, but put your shoe inside the drum against the outer edge, and look at the fit, the shoe material should be touching the drum pretty much all the way around.
If it is not, it is possible, that when you applied the hydrualic pressure too it, that the shoe bent more then the wear material would allow and it cracked at the weakest point (the rivet holes)
Could be wrong stuff, could be things at each end of the tolerance spectrum, could be a bad day at brake shoe reliners are us.
New shoes, and new drums, you would like to think they all fit together well, but that is just not always the case.
