BROKEN BACK BRAKE SPRING

You need to install a brand new rear drum brake spring kit. Most likely. You have a broken brake shoe return spring it sounds like. That is if it is drum brakes.

if you have rear drum brakes a return spring that pulls the brake shoes back to the unapplied position or a hold down spring may have broken which is now causing the brake shoes on that wheel to be applied causing the drag not all people bought there cars and trucks with 4 wheel disc brakes it was cheaper and didn't matter to them they just wanted lower $$$ check it out if this is the case you'll have to turn the adjuster star wheel inside the drum all the way in to get the drum off because the brake is applied it will be a pain but you'll get it you must use a brake spoon or a flat blade screw driver and a smaller one to lift up the return spring arm from the star wheel if this one is broken you will have to try to pry the drum off then buy a spring kit from auto parts and some brake tools if you don't have them already and change all the springs one by one so you don't get confused but also try to get a rear brake shoe diagram in case everything has fallen apart inside and you remove the drum and find a whole bunch of parts on the floor in front of you the diagram will give you the aid that you'll need if you have never done this before most of all inspect that wheel cylinder for leaking fluid if this is so replace it now good luck LATER MAN!

Pull the brake drum off to see what's binding-brakes won't retract, emergency brake is stuck, a brake shoe return spring may be broken. Raise the rear and take both drums off to compare left and right side brakes and all the parts therein.

There is always a spring that works as a return spring to pull the brake lever back up. Please check the brake pedal and see if this return spring is unhooked or broken. Do the needful when located.

Brake Drums & Brake Shoes Removal & Installation To Remove:
Rear Drum Brakes

1. Raise and safely support rear of vehicle.
2. Release parking brake.
3. Remove rear wheel assemblies. NOTE: If brake drum is stuck, install two 8 mm bolts into threaded holes and tighten evenly.
   
4. Remove top return spring, front and rear shoe spring clips and hold-down pins.
5. Remove anti-rattle spring and adjuster spring. NOTE: Note position of operating lever prior to removal.
   
6. Remove bottom return spring.
7. Remove clip and washer and detach parking brake cable from rear shoe.
8. Remove brake shoes.

To Install:

1. Lubricate all brake shoe contact points with appropriate grease.
2. Place operating level into position on hub.
3. Install rear brake shoe and connect parking brake cable to rear shoe with washer and clip.
4. Install front brake shoe and install bottom return spring.
5. Install hold-down pins and spring clips.
6. Position operating lever and install top return spring.
7. Install anti-rattle spring and adjuster spring.
8. Install brake drum and screws.
9. Adjust brakes and install rear wheel assemblies.

There is a switch that is connected mechanically to the rear brake mechanism. If the return spring has broken or the switch is broken or misalligned, that can call your problem as can the front break switch, if fitted.
Hope that helps.

There are four possibilities. From worst to easiest to fix: (don't worry, a link provided below has diagrams of all the parts in exploded view with part names)

1. There are two springs holding the brake shoes firmly against pivot post and brake lever cam, the ends of these can wear through and break. These provide most of the spring tension felt in a cable operated expanding shoe brake. Requires wheel removal and simple removal of brake hub to access.

2. The cam that expands the shoes (when rear lever is actuated) runs through a waterproofing rubber grommet. This grommet can often tear and bind up, reducing the return spring's effectiveness.

3. There is a spring behind the brake's foot pedal frame mount and the plate that pulls the front of the cable end. This maybe either dislodged or the angled ends broken off.

There is a compression spring at rear wheel end of cable, between cable stop and lever arm. This can be removed, stretched and replaced or packed with spacers to provide additional spring.

Check site below: Wheels/tyres/drive - Rear wheel parts #6 (shoe springs) part #7 (brake cam)
Frame/Footrests - part #4 (pedal return spring) part #9 (compression spring)

If this helps let me know below, ...Cheers.

http://www.bikebandit.com/houseofmotorcycles/2004-yamaha-motorcycle-xv250s-virago-250/o/m8460

its the rear brake light switch thats not working it could just be stuck in,,,the switch is near the foot brake leaver

Could be trash in the brake cylinder or could be brake return spring loose or broken

Brake Shoes Removal & Installation To Remove:

1. Raise and safely support rear of vehicle.
2. Remove rear wheel assemblies.
3. Release parking brake.
4. Remove brake drum.

Rear brake shoe assembly

1. Using an appropriate brake spring tool, unhook upper return spring from rearward brake shoe.
2. Push retainer springs IN and turn to remove tension pins.
3. Lower brake shoe assembly and remove lower return spring.
4. Remove brake shoe assembly from back plate.
5. Disconnect parking brake cable from lever and remove brake shoe.
6. Remove parking brake lever from brake shoe.

To Install:

1. Install parking brake lever to rearward brake shoe.
2. Secure lever to brake show with a NEW U-clip.
3. Pinch U-clip closed.
4. Connect parking brake cable to rearward brake shoe.
5. Install self-adjuster lever spring on front brake shoe.
6. Assemble clevises, adjuster bolt and upper and lower return springs.
7. Apply a light coat of grease (Molykote 44MA or equivalent) to sliding surfaces.
8. Install brake shoe assembly onto back plate.
9. Install tension springs.
10. Using an appropriate brake spring tool, unhook upper return spring to rearward brake shoe.
11. Install brake drum.
12. Install rear wheel assembly.
13. Lower vehicle.
14. Adjust self-adjusting brakes by pressing brake pedal several times.