what rights do co-ops have?

I currently live in an apartment on the upper east side, which i own outright and have no debt. I recently decided to take a loan out on the property, but my co-op insisted that I put one year's worth of maintenance into escrow? Do they have such a right? I have never been late on my maintenance payments and am not a problem tenant. I have been living in the building for a few years now and my financial situation has not changed. I am just trying to take advantage of the low interest rates. The amount I am looking to finance by the way is less than 40% (conservatively) of the apartment's value. This is yet another example that management companies and building co-ops have nothing better to do than make life for their tenants miserable.