I like chase.
Does he lead?
If not id get a halter on him and get him giving to pressure and leading.
Probably leave a rope on for him to drag for a couple days before that.
Id get him in a round pen and get him changing directions and doing a little ground work.
Have respect then start working with touching his body. Neck first, shoulder, back, take it slow. Eventually get to legs/feet.
Id do that every day. Well not longing but just messing with him.
Im doing a colt of my own this way.
Only once he gave to pressure and accepted that rope he is a lot better. In 2 days he let's me mess with his legs. No problems with belly rubs, only a little face shy..