How to change time and date in Rolex GMT + Master watch?

This watch will keep great time if it has been wound via crown.

Yours is the original GMT Master. The GMT Master II allows the GMT hand and the regular hour hand to be set differently but not on your older model. On yours, the regular hour hand the the GMT hand are fixed so that if the triangle on the rotating bezel is at the top, the GMT hand will indicate local time. To indicate time in a 2nd timezone, rotate the bezel to orient the time to the GMT hand. There's a copy of the original instructions posted at: http://www.rolexforums.com/showthread.php?t=45269

This happens due to friction between the wheels and cannon pinion in watch movement, especially if your Rolex has not been serviced for a few years, however, it should not affect timekeeping. I'd advise to show your watch to the watchmaker and clarify exact cause of this.
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first click changes the date if you turn one way, but turning thr other way should change the 24 hour hand.

There isn;t any downloadable manuals for Rolex watches, but operation of Rolex Day-Date is very simple:
1) when you unscrew the crown, it is in winding position,
2) when you pull out the crown to the first click, it is in day and date setting position (depending wich way you turn the crown).
NOTE: to adjust the day or date, previously you have to advance hands forward, passing 12 o'clock (midnight) mark and stop advancing at 4.00 a.m. using the crown in position as described in chapter 3. When done - push the crown fully in, then pull out to the first click and only then adjust the day or date.
3) when you pull the crown further out to the second click, it is in time setting position.
To find the daytime or night time on the watch: pull out crown to the second click and advance watch hands forward till you pass the 12 mark on dial. If the date changes as you pass it - it is the night time (midnight). If the date do not change as you pass it - it is the daytime (noon).
After all settings being done, allways screw the crown back down as it protects the watch from water and moisture.
Never use watch in sauna- it's not designed for that.
Do not forget to rate, please.

There isn;t any downloadable manuals for Rolex watches, but operation of Rolex Day-Date is very simple:
1) when you unscrew the crown, it is in winding position,
2) when you pull out the crown to the first click, it is in day and date setting position (depending wich way you turn the crown).
NOTE: to adjust the day or date, previously you have to advance hands forward, passing 12 o'clock (midnight) mark and stop advancing at 4.00 a.m. using the crown in position as described in chapter 3. When done - push the crown fully in, then pull out to the first click and only then adjust the day or date.
3) when you pull the crown further out to the second click, it is in time setting position.
To find the daytime or night time on the watch: pull out crown to the second click and advance watch hands forward till you pass the 12 mark on dial. If the date changes as you pass it - it is the night time (midnight). If the date do not change as you pass it - it is the daytime (noon).
After all settings being done, allways screw the crown back down as it protects the watch from water and moisture.
Never use watch in sauna- it's not designed for that.
Do not forget to rate, please.

No, there isn;t any downloadable manuals for Rolex watches, but operation of Rolex Datejust is very simple:
1) when you unscrew the crown, it is in winding position,
2) when you pull out the crown to the first click, it is in date setting position,
3) when you pull the crown further out to the second click, it is in time setting position.
To find the daytime or night time on the watch: pull out crown to the second click and advance watch hands forward till you pass the 12 mark on dial. If the date changes as you pass it - it is the night time (midnight). If the date do not change as you pass it - it is the daytime (noon).
After all settings being done, allways screw the crown back down as it protects the watch from water and moisture.
Never use watch in sauna- it's not designed for that.
Do not forget to rate, please.

Let me start by saying that I own this watch and LOVE it!

To set the time you need to pull the crown all the way out to the furthest position.

To set the date you need to have the crown in the position in between the "winding" position and the "time set" position. Basically, pull the crown out till you hear/feel 1 click to wind, 2 clicks (total) to set the date, and 3 (total) clicks to set the time. I always set the date first to 1 day behind the current date. I then move the crown out to set the time so that I can set the watch to either AM/PM depending on the actual time. For example, I set my Rolex today (the 5th of January at 3pm - just an example). I would first move the crown to the date setting function and move it to January 4. I would then move it out one more position to set the time. I would go around the watch until the date changed to the 5th and then go around from 12 to 12 to change from AM to PM. I would then move it to the 3 and then I'm all set. This is helpful because it will ensure that your date will correctly change when the day changes and not be 12 hours behind.

If it still under warranty take it back to rolex, other wise take it to an indpendent watchmaker they should be able to fix it for a small fee. The watch probably doesnt need a service yet if it is new.