How to replace a Treadmill Precor 9.31 belt - Precor 9.31 Treadmill

Please see here for some Precor spares, there are many belt sizes to choose from:

http://www.partsfortreadmill.com/catalogsearch/result/?q=Precor+

and here for dismantling your treadmill and changing the belt:

http://www.treadmillsrepair.co.uk/2013/12/belt-for-treadmill-replacement-and.html

Replacing a Treadmill Running Belt and Deck Following is a basic guideline of removing and replacing the running belt and deck on a treadmill. Due to different brands and designs of treadmills, the following should only be used as a guideline. If any of the information is not exact to the treadmill being serviced, refer to the service manual or call Sportsmith for further help. Tools Needed: Phillips Screwdriver, Set of Allen Wrenches, Set of Box End or Open Face Wrenches (Tools needed may vary depending on treadmill. )

1. Switch the Power off on the unit.
2. Next, unplug the unit from the wall.
3. Remove the finger guard retaining screws and carefully remove the finger guards from the deck at each end of the rear roller.
4. Loosen each rear roller bolt by 10 full turns. Then count the remaining turns necessary to remove the rear roller bolts. Remember to write down the number of turns needed to remove the bolts in each side for future reference.
5. Carefully remove the rear roller from the unit. Clean any wax or debris buildup from the roller and place it aside.
6. Raise the shroud and secure it with a bungee cord.
7. Work the drive belt off the motor pulley by hand turning the flywheel while pushing the belt aside.
8. Now remove the front roller retaining bolts.
9. Carefully remove the front roller from the unit. Clean off any wax or debris buildup and set it aside.
10. Loosen and remove the deck mounting hardware.
11. Move the deck toward the left side of the frame to free the deck from the right side. The deck will move down once the frame has been cleared.
12. Remove the deck and belt by raising the right side edge of the deck over the frame rail and sliding it to the right to remove.
13. When installing a new belt or deck it is important to note that a new belt and deck surface should always be installed together. Failure to adhere to this guideline will severely shorten the life of the newly installed parts. Some decks can be used on both sides. However, be sure that each side is only used once. Be sure to install the belt in the proper direction on the unit.
14. Install the belt and deck by first putting the belt on the deck, and then installing them from the right side as a unit.
15. Be sure the deck is lined up with the frame and push the deck to the left side.
16. Now carefully lower the right side of the deck to insert it into the frame rail and then push the deck to the right as far as possible.
17. Re-install deck mounting hardware. (Check with mfr. for proper torque during install process.)
18. Carefully place the front roller on the deck under the belt and push it forward into place, while placing the drive belt on the inside of the drive pulley.
19. Replace the front roller bolts. (Check with mfr. for proper torque during install process.)
20. Now spin the roller by hand while pushing the drive belt onto the pulley. Be sure to spin the roller several times to insure complete installation of the drive belt on the pulley.
21. Install the rear roller into unit. Carefully start each bolt and turn one to two threads to ensure no cross-threading has occurred.
22. Tighten each rear roller bolt the number of turns you kept earlier for reference.
23. Now, Plug in and power on the unit.
24. Carefully remove the bungee cord from the shroud and lower it back into place.
25. Start the unit at a very slow speed and check for proper belt alignment. Remember to start at the slowest speed possible and be ready to stop the unit quickly if needed.
26. If the belt is moving to right side of unit tighten the right roller bolt, If the belt is moving to the left side of the unit tighten the left roller bolt until the belt is tracking properly.
27. Caution: make very small adjustments such as 1/4 turns and then watch the belt for several moments before making another adjustment.
28. Once the belt is tracking properly walk on the unit at a slow speed and check for belt slippage on foot fall. If this is happening tighten each of the rear roller bolts equal turns until the slippage is no longer occurring. Caution: make very small adjustments such as ¼ turns and then watch the belt for several moments before making another adjustment.
29. Now use the unit at a jogging speed to check for belt travel or slippage.
30. If slippage still occurs make small equal adjustments (1/4 turns) to both sides of rear roller and re-test.
31. Install the finger guards once you have enough clearance from the rear roller.
32. Some manufacturers require wax or lube during the install process, please consult your owner's or service manual for further information regarding this.
33. This concludes our instructions of how to install a replacement treadmill belt and deck.