RS485: Full duplex?

Actually , I am working on a mechanism in which arduino1 sends a request to arduino2 for data via rs485. Arduino2 receives the request and is supposed to send data over to 1. But arduino1 is receiving nothing.
I thought it had something to do with the resistors.
Now, I am beginning to wonder where I have gone wrong. I put in hard-coded delays to make arduino 1 wait for the data. Is that causing problems?