Is the drive pulley suppose to be tight? Or does it slide off the shaft?

I'm not sure what you mean by "Common Pulley". There is a flat belt that goes from the motor shaft to the big round pulley on the transmission. There is also a "V" belt that goes from the transmission to the brush roll. You have to be careful how you install the "V" belt because it has a pulley that takes the slack out of the belt when you pull the handle back if you have the lever in "Carpet" position. The belt does not get tight until you pull the handle back which leads many people to believe the belt is too long or the pulley is not working properly.

• A list of things to check (unplug vacuum FIRST):
  1. All contact surfaces for belt are clean of build up, that can push belt in one direction
  2. Brush roller is not flip end for end (the pulley on the motor shaft should line up straight with the worn area of the brush roller).
  3. The guard on the bottom (covering the belt and brush sides) is clean and free of build up.
  4. The ends of the brush roller are free of build up and the bushings that slide in the end are inserted in the correct direction, this can cause the brush roller to set at an angle and cause the belt to slide in one direction.
  5. You have the correct replacement belt, I have found the wrong belt placed in the packaging for my vacuum at the factory once before (check manufacturers website).
  6. If the brush roller is extremely worn, it could be time to replace but this is very unlikely.
  7. Rotate the motor shaft by hand and see if there is any wobble, the pulley could be on crooked or bearing has failed causing slop in the motor shaft.
     

Instructions1 Place the riding mower on a level surface and set the emergency brake. Open the engine or tilt the seat back to gain access to the battery. Disconnect the negative battery cable with a socket. Turn off the main fuel petcock valve from the tank to the carburetor. Set the attachment clutch in the "Disengage" position. Set the motion control lever to neutral. Place the mower deck lift lever in its lowest position to drop the deck.
2 Pull the belt against the engine drive pulley, then pull upward on it and slip it off the pulley. Unclasp the small clutch retainer spring from the pulley bolt. Detach the big retaining spring and then slide the collar sleeve off. Shove the housing guide out from the br
3 Pull the retainer springs off that hold the rear suspension arms to the rear mower deck bracket. Disconnect the front link arms that hold the front of the mower deck to the chassis. Pull the lift lever to put the suspension arms at full height.
4 Slide the mower deck out from the bottom of the tractor. Tilt the mower deck and prop it up with wood blocks. Use a stiff cleaning brush to remove all mud, twigs and grass clumps. Wipe the top of the deck and undercarriage with a rag.
5 Un-thread the belt from around the idler and mandrel pulley. Place the new belt around the mandrel pulley and idler pulley first, then stretch it up to the drive pulley and loop it into the pulley grooves. Make sure the V part of the belt rests inside the pulley.
6 Use the lever to raise the suspension arms on the deck. Push the deck back under the tractor. Lower the suspension arms and replace all the retaining springs in reverse or the order in which you removed them. Slide the sleeve back into position and secure it with the spring. Reattach the spring to the anti-sway bar. Shove the housing guide back into its bracket.
7 Raise the mower deck with the lever. Reconnect the negative battery cable with a socket. Turn on the fuel petcock valve. Start the engine and engage the main drive lever. Test-drive.

THanks

Ok with the front of the vacuum facing you look on the left had side of the power head then follow these steps.
1.Remove the door by removing
the hold down screw located on
side of power head.
2.Slide the door forward by
prying open with a screwdriver
or coin.
3.Remove the belt from the brush
roll pulley and the motor drive
shaft.
4.Loop the new belt over the
motor drive shaft. Place the
opposite end of the belt on the
brush roll pulley.
5.Rotate the brush roll three (3)
complete revolutions to ensure
that no part of the belt is
overhanging the end of the
motor drive shaft.
6.Replace the door by sliding it
into the groove at the bottom of
the housing. Replace the hold
down screw.

To change the belts, make sure the vacuum is not plugged in. Lay it upside down and remove the screws holding the bottom plate on. Remove the bottom plate, pull the brush roll out noting how the belt goes so you will know how to put it back together. Especially how it goes around the idler pulley. Remove both belts, replace both belts, install the V belt onto the transmission first then around the brush roll and put the brush roll in place. Install the flat belt around the motor shaft and then onto the transmission pulley.

This is an easy fix. a lot disassembly required, you will need to gain access through the belt side to the singer cover plate,four clips hold it on from the back side. Once that is off, two screw hold small access plate which is under the letters Sin, remove plate, rotate shaft to access screw through opening which holds Vertical Top Shaft Gear, Singer # 155819 in place. Remove bottom cover, locate belt pulleys (2), remove cam tensioner, with a hex wrench remove pulleys, this makes it easier to remove lower belt. with a long thin, blade screwdriver, loosen screw on gear (through small access cover), slide shaft downward Rand R gear, reverse process, done. Be sure you document removal, take pictures, mark references with marking pen.This makes reassembly easy. I just replaced mine, I am handy but not an expert, hope this helps you...

ok its fairly simple the belt you need is 38528-040. Start by first removing the little slide button from the height adjustment switch. just pull strait up and it will pop off. it will need to be out of the way. turn over the vacuum and there will be 2 spring clips that release the bottom cover and give you access to the brushroll. now you must remove the top cover. there are 4 clips, 2 on each side. Use a flat head screw driver to pry one clip at a time, it should pop fairly easy. now that you have all the clips free release the handle assy and the hood will lift off. inspect brushroll for wear and free rotation. if its bad replace it. now install the belt on the brushroll first, install brushroll and pass belt through belt channel. Stretch belt with your hands until you successfully get it on the motor shaft. (Its supposed to be pretty tight i guarantee its the propper belt) rotate brushroll to properly align belt then snap top cover, and bottom brushroll cover back in place and dont forget to put the small button back on top of the hood.

After disassembling the unit to gain access to the hoses, the electric valve and the pump, I was able to determine that the pump was not working. NOTE: If you plan to test if the pump motor is working or not you must first remove the belt that drives the brushes from its motor pulley. This is done by first removing the C-ring that holds the pulley on the motor shaft, then slide the pulley, belt with it, off the shaft.This will allow the motor to turn without spinning the brushes. With the unit plugged in and turned on, pull the cleaning solution/water trigger. The pump motor has a short shaft sticking out and it should spin. You can touch the shaft with a finger and feel if it is spinning or not. I have no idea if the motor can be purched separately or if it is available only with a pump assembly. I also have no idea if you can buy either. I reparied the motor, but I will not go into detail on this at this time. Sufice it to say that the shaft was in dire need of lubrication. Most people would not elect to disassemble the unit to the extent that I did and I would simply recommend taking it to an authroized service center.

Yes, the motor shaft is also the pulley.

1. Remove the lower plate
   
2. Carefully lift up on the agitator assembly until it clears both sides of the nozzle housing.
   
3. Remove the belt from the motor shaft by sliding it off between the end of the shaft and the nozzle housing.
   

3.4.2 Installation

1. Place the belt around the motor shaft.
   
2. Start the new agitator assembly back into the nozzle housing by placing the side opposite the belt partially into the slot. This will hold the agitator in place and leave both hands free to place enough tension on the belt to allow that side of the agitator to return to the nozzle housing slot.
   
3. Place the belt around the agitator pulley on the agitator assembly.
   NOTE: There is a place for the belt to fit on one end of the agitator assembly only. This is the agitator pulley.
   
4. Use both hands to pull the belt tight, and slide the agitator assembly firmly into the slots on each end of the nozzle housing.
   
5. Rotate the agitator assembly by hand to insure nothing rubs and to check for correct assembly.
   
6. Replace the lower plate