Not very educated on the topic :-\
The FAQ has a section regarding Post-Independence Fragmentation of Latin America, which you may find helpful.
It includes:
Why is there not one united nation across all of Latin America? by /u/LegendaryTubaHero
Why did North America split into 3 countries and South America split into 15 though they were colonized similarly by /u/Yodatsracist
During the early 1800s as Spanish holdings in South America began to vie for independence, was there any concerted effort to create a "United States of South America"? If so, why did it fail? by /u/ThucydidesWasAwesome