Sounds like fan inside blower housing is hitting something when motor is running.

RICCAR SIMPLICITY SUPRALITE RSL MOTOR and FAN

Its looks the same as a Kirby its done with a nut on the axle on the armature of the motor.

This is usually caused by a belt being too tight or the wrong size. It can also be caused by something wrapped around the brush (like loose thread from a rug or yarn, shoestring etc. Try inspecting the brush and belt.

You may have to slip a small screw driver into an open slot of the motor housing to provide a stop for the armature so that you can break the lock nut loose. Becareful to not cause ant damage the armature.

Tear apart all hoses and make sure no clogging, also take apart to expose motor and make sure their is no dust on motor, this will cause symptoms you are describing, another thing check Impeller fan and make sure the fan is running and not blocked if fan is not working then will need to replace Impeller.

sometime you have to take the motor apart and hold the armeture but you have to be careful not to damage it or if you have a good impact it will come loose with that

Yes, I would say the crack is causing the screaming sound.

Usually the fan (impeller) is held on with a left-hand nut. To remove it, you have to hold the motor somewhere (sometimes you can just hold the impeller), put a wrench on the shaft nut and turn it clockwise. The impeller should then just pull off (with possibly some wd-40 and a little muscle).

on the bottom you will see 2 levers that slide to the side.turn those and the head should come off.there should also be a knob on the top to disengage the belt.once you get the head off you will be at the motor and you will see the impeller.you will have to take the motor housing apart to replace it though.the impeller should be held on with a nut in the middle

I have a similar bagless model U5757-900 that is shutting off. I disassembled the unit, and what I found is that the motor front bearing had accumulated enough grime so that the bearing locked up. When this happened, the bearing outer shell spun in the plastic housing, causing it to soften, from friction heat. This allowed the motor shaft to become off center from the normal, centered axis of rotation. Once this happened, the rotor inside the motor began to rub against the stator, the fixed part of the motor inside. This loaded down the motor, causing excessive current draw, which caused the overheat switch to activate, shutting down the machine.

In your case, it might not be as bad as in my case.

Remove the dual-cannister dirt cup.

To find out, disassemble the unit lower section: on bottom, remove 4 screws around the rotating brush housing. Remove the brush cover, then remove the brush, then remove the belt. Remove the wide plastic housing behind the brush. Remove the two screws, from the bottom, that retain the upper hood. Remove the hood.

On the back, remove the two screws and hose retainer going from the base to the upright section. This releases the hose from the lower section.

Now press the tilt release, and lay back the upright section. Remove the four screws, two on each side, from the trunnion caps, where the upright section tilts on the lower section. Remove the trunion caps. Remove the upright section from the lower section.

Remove the headlight cover (2 screws).

From the back, remove the single screw retaining the bezel above the headlight area.

Slide the bezel upwards and remove.

Remove the four screws that retain the motor cover clamshell. One is from front, and other 3 from rear.

Open motor clamshell halves to expose motor.

Note orientation/position of the three wires on the motor, and remove those wires. Lift motor out.

To open the motor, gently tap the edges of the impeller housing (aluminum shell) on the edge of the shell, in the little gaps around the shell.

Using a 1/2" socket, remove the nut in the center of the impeller. This is a LEFT HAND NUT. TURN RIGHT TO LOOSEN IT.

Gently wiggle the impeller while pulling until impeller comes off of motor shaft. Use a glove so the impeller doesn't cut your hand.

Remove the large flat washer on the motor shaft. Remove the small sleeve from the motor shaft.

On the brush end of the motor, using a small screwdriver, pry out on the brush holders. Set them aside.

Remove the two screws holding motor together. Seperate the motor front from motor rear. Withdraw the motor rotating part.

Look into the inside of the stator, inspecting for bright, shiny areas where the rotor may be dragging on the stator. If you see these, then the front bearing, in the plastic motor frount, is fried. I don't think Hoover sells this part alone. Also inspect the plastic front bearing retainer to see if there is any melting that has allowed the bearing to become off center.

In any case, if there is scrubbed out places inside the stator, then the motor requires replacement, about $70 for the motor... You might be able to find an entire new vac for less... or, like me, find one on the side of the street where someone has tossed out a unit.

You may luck out and find that the impeller unit is just filled with some trash so air cannot get to the motor for cooling... or you may have a shot motor.

I would make sure it is the motor first by isolating the sounds to just the motor. Take off the dirt cup, both filters, and belt, then run it and see if the sound is still there. If it is, you need a new motor. If it isn't, you need to look for a clog, or bad roller bearing.

To take the motor out first undo the wiring running down the backside of the unit inside of the switch housing. Then take the four screws out that hold the outer motor housing on, and the rest pops apart. Once you get inside, the gaskets make it a really tight fit, so you might have to hit the motor shaft with a rubber mallet to get it out and use penetrating oil on the bottom gasket to get the new motor to slide back in.

I guess there is no easy explanation. Let me know how it goes.

I obtained a bearing from McMaster Carr (mcmaster.com) installed it and the carpet cleaner works
once again. I used a double-sealed bearing (part number 5972K221) rather than a double-shielded
bearing (part number 5972K36) which was of the type that failed. The original problem probably
arose from the dirty water tank getting so full that water/detergent is sucked into the motor. I did not
examine the unit to see if an interlock is supposed to prevent this from happening. In retrospect,
I probably should have gone for a stainless bearing (part number 6153K71) which costs $11.56
rather than the $4.26 for the one I selected. The repair was fairly straight-forward but confusing at
times. The motor is under lower front cover (rounded with air vents). This is held on by two
Phillips-head screws set deeply in holes in the back. However, the mounting tabs of the lower
front cover are under the upper front cover. It may be possible to bend outwards the lower part
of the upper cover, but I removed the upper cover. In addition to the two screws already mentioned,
the upper cover is held by two screws passing through the protrusions to which the clean-water
tank snaps are attached. You have to remove these snaps to pull the upper cover apart. After
you get the motor/housing out, you can remove the plastic blower housing with four screws, but there
is a metal blower housing underneath it that has to be pried out. Since the plastic one pries against
tends to break, I ended up repeatedly catching the edge of the metal housing with a screw-driver
blade and then rapping the screwdriver with a hammer. After removing the impeller, the motor can
be pulled free of the blower housing. After removing the brushes, it took a while to realize that
the brass-colored brush housings had to be slid almost all the way out to uncover the two screws
that allow the armature to be removed from the field coils. The bearing is press fit in place, so you
need a puller or some equivalent arrangement to remove the bearing. Not having a press, I used
the impeller nut to press the new bearing into place. It had to be tapped lightly with a hammer
at first. One the nut could grab a thread, it was used to press the bearing into place. Since you
run out of thread before the bearing is fully seated, you need to add some spacers and repeat
the process. I used a stack of washers. When removing he brushes, label their orientation so
that they do not add excessive drag when reassembled. So far, the repaired cleaner has run about
an hour without problems.