Whenever replacing the belt on these StarTrack treadmills the deck should be flipped to the unused pre-waxed side at the same time. If the deck has already been previously flipped then a new deck should be ordered.
You should also order 8 new recessed deck bumpers, because the get very brittle. They would need to be installed on the side of the deck now facing up after removing the old ones from the used side if simply flipping the deck.
Here is the disassembly sequence for belt replacement and flipping, or installing a new deck:
1.) Unplug the treadmill.
2.) Loosen the two screws on the front of the motor cover, and remove the two side screws, then remove the motor cover.
3.) With a 1/2″ wrench loosen the bolt underneath the left side of the treadmill that secures the left handrail to the left side rail. Once removed from the threads, simply allow the head of the bolt to slide down and rest on the floor. There is no need to lift the side of the treadmill to remove this long bolt.
4.) With the appropriate size hex or allen wrench, remove the two screws underneath the upper handrail.
5.) Slightly lift the lower part of the handrail out of the plastic side rail cover the work the upper portion of this lower handrail back and forth and slowly work out from the upper portion. Be careful of the wire harness for the off/on button for the hand rail passes through this joint. You will need to carefully disconnect this once the connection is exposed. Remove and set aside. These are often very rusty inside so some rust buster, etc. may be good here. Be careful not to get any rust buster or oil on the connections.
6.) Remove the plastic side rail cover by prying up on the outer edge, and set aside.
7.) Remove the two rear roller bolts completely, remove the left finger guard (3 small phillips screws) and set aside. Then remove the rear roller out from the left side. No need to remove the right finger guard, or the side rail end caps in my opinion.
8.) There is s dirt guard just in front of the the front roller that must be removed to provide enough clearance to remove the front roller. Remove the 5 Phillips screws holding it in place and set it aside.
9.) Remove the two hex bolts that hold the front roller in place, then remove the right side of the roller up through the clearance slot, then slide out the left side of the roller and slide the drive belt off and over the end to allow you to slide the front roller out of the tread belt.
10.) There are two deck stop Delrin rods in the left side rail that were exposed after removing the black plastic side rail cover. These are held in with a Phillips screw and must be removed to provide space to remove the tread belt and deck. There is a third one at the base of the treadmill near the rear roller, but I have never found it necessary to remove this one.
11.) With the 2 black plastic Delrin rods removed you can now slide the deck sideways to the left side working from the right side. Sliding it all the way over you should have just enough clearance on the right side to lift the deck up and out. You may need to take a large flat pry tool to coax it up and out.
Many people remove the right side rail and the side rail cover to provide more room, I have never fond this necessary.
12.) With the deck and belt out, remove and dispose of the old belt. If flipping the deck you will need to remove the 8 recessed deck bumpers. I recommend installing new ones on the other side (the new up side) but the old ones can often be reused. They just get hard, brittle and crack with age.
13.) Be sure to clean off the dust and dirt from the unused pre-waxed side. Then slide on the new tread belt.
14.) Simply reverse the order to reassemble the treadmill.
Tip: I usually from all of the screws and bolts that I remove into the motor cover turn upside down. Then after removing the last bolts from the front roller I spray all of these rusty screws and bolts with a rust buster type product.