As soon as I step on the belt it quits running

Call Treadmill Doctor at 800-750-4766 or follow this link, this may help.

http://www.treadmilldoctor.com/Treadmill-Looses-power-when-I-setp-on-the-belt?utm_source=fixya&utm_medium=cpc&utm_campaign=mendi

I would try to tighten the rear roller a little and see if that helps.
1 start the treadmill and operate it at 1.5 mph then hild onto the handle bar and plant your foot against the belt at the front. If it slips tighten the roller 1/4 turn on each side. Then try the slip test again and repeat the process, do not tighten it too tight that will cause the belt to fold in teh center and be ruined. You May quite possible need a new belt. Take the belt lose and look at the underside and see if it;s glazed (shinny) or has pieces missing under the center of the belt, if so replace the belt and also clean the rollers front and rear, also flip the deck over it shoudl have a wax coating on the other side if that hasn;'t already been done.

Tighten the alternator belt..

hi, its seems like the belt on the motor has either slipped or just needs to be tightened more, best way to find out is open the front cover showing the motor, step on the treadmill and see what happens. if the motor is still spinning and the belt isnt then its the belt, check the tension if it is loose just tighten the belt. if the belt and motor are fine then its the running belt that needs to be tightened, to check this just put your hand under the belt and try lifting it, if you can easily lift its 2 0r 3 inches then its ok, but if you can lift it alot more this will need to be tightened, hope i have helped.

Unplug unit then remove motor shroud the walk on the belt normally and try to stall the belt to make it slip. Be careful during this test. If the problem is in the drive belt, either the drive belt will stop when stalled or the front roller will stop when stalled.
Find the set bolt(s) on the motor. This is typically run through only one side of the motor mount or may be on both sides but it does not run the full length of the mounting..
Look for a bolt that will tension the motor. If it has this bolt, it typically runs in the same direction parallel with the drive and walking belts. If your treadmill is not equipped with a bolt as described above, the drive belt must be tensioned by hand. While one person applied increased tension to the drive belt, the other person should tighten the motor set bolt(s) that are described in Step If your treadmill is equipped with this bolt (very few are) the repair will only require one person.
If the motor, drive belt, and front roller continue to turn when the walking belt is stalled, the problem is with the walking belt slipping on the front roller.
If the walking belt slips when walked on. Using the allen wrench, turn both rear roller bolts clockwise, 1/4 of a turn. When the walking belt is correctly tightened, you should be able to lift each side of the walking belt 3 to 4 inches off the walking platform. Be careful to keep the walking belt centered. Plug in the power cord, insert the key and carefully walk on the treadmill for a few minutes. Repeat until the walking belt is properly tightened.

just in front of the altenator, there is a 10mm bolt, tighten that and it will tighten the fan belt .
these belts are quite tight, make sure the one you have is the correct length, sometimes the suppliers will send one that is close to the correct size, and is sometimes a few milimeters smaller.

You dont normally have to loosen anything else, but the easiest way is to put the belt on the alternator, tensioner and power steering first, then ease the belt over the ridge of the crankshaft last, one rib at a time, but evenly all the way around the pulley.


for more step by step instructions with proper diagram please click on this link directly
http://www.howtodothings.com/automotive/a3038-how-to-replace-a-fan-belt.html
---------
this will help.thanks.

More than likely your drive belt needs to be tightened. Lower cover needs to be removed to access this drive belt.

tighten running belt evenly

There should be adjustment screws on the back left and right sides. The screws will be horizontal with the tread, and probably need an allen wrench to tighten. If the tread runs straight, tighten each side 1/4 turn at a time to keep them even. Check the tread after each adjustment, and stop as soon as the tread quits slipping.

This is caused by one of three problems. First and most likely, the walking belt is loose. To tighten the belt, start by locating the two bolts that adjust the rear roller (one on each side of the unit in the back). Run the unit at about 3 mph. Tighten the bolts a 1/4 turn at a time. Make sure that what you do to one side, you MUST do to the other side or the belt will get off center. After you tighten it 1/4 turn, check the belt to see if it is still slipping. If it is then tighten the belt 1/4 turn again. Continue until the belt does not slip, but do not tighten the bolts more than 2 full turns. If it takes more than 2 turns then something else is the problem. The second problem that it could be is the drive belt might be loose. To tighten the drive belt, start by removing the front cover. loosen the bolts around the motor then tighten the drive belt by tightening the motor adjuster bolt. Once the drive belt is tight, tighten the motor back down. The third problem that it could be is the walking belt could be worn and need to be replaced. Let me know if you have any questions.