Looking up Coll-O-Crimp T-400 on Google, I get a lot of hits, although quite possibly rather expensive dies.
Is the Coll-o-crimp made by weatherhead? I used the following search criteria on E-Bay and came up with quite a few dies.
hydraulic hose (dies,collets,die,collet) weatherhead
or simply.
(dies,collets,die,collet) weatherhead
You also get several hits with
(dies,collets,die,collet) (t400,t-400)
Of course you will have to verify models and applications.
It is quite possible that if you changed all the rings, you could also use different brands or models of dies in your crimper/press.
Everything I read indicates that it is always best to verify proper compression by measuring the crimped fittings.