No rear brakes, pedal goes all the way down and brake lights don't work, but they work off the fronts

Hi The back brake light is on, right. You need to check two things: 1 there is a spring and switch connected to the rear brake pedal. Just kneel down and look at the pedal and follow the linkage back to the rear brake mechanism. Somewhere there should be a connection (spring or wire) that goes to a switch. When you push the brake pedal down the spring or wire pulls a piece inside the switch that makes two contacts in the switch complete a connection that turns the brake light on. This switch must be free and working properly and not sticking as well. It also needs to be properly adjusted so that it will turn off and on at the right times. Most of the time this switch gives the problem.
2 Newer bikes have a switch on the front brake as well. Use the same theory and test procedure to test and fix. If it is a hydraulic clutch (they use brake fluid) there could be a Hydraulic activated switch, make sure it is working properly and not sticking.
If the rear brake is Hydraulic there could be a mechanical switch or a hydraulic switch used. Sorry for the long answer. I hope this helps. Rod

Check for leaks around calipers....front and rear. Sucking in air somewhere...

"pedal all the way down, no movement of caliper"
Sounds like hydraulic problem.

Check if you have enough brake fluid.

If so, it could be a bad master cylinder.
Rear brake light switch won't work without hydraulic pressure (which also works the caliper), while front brake light switch is mechanical.

try changing the brake switch in the floor behind brake pedal.... pedal activates in when used, sending power to brake lights

It sounds like the rear brake pressure switch is bad. The wires for the front brake light switch are wired in parallel to the this switch. Replace the pressure switch in the metal brake line coming from the rear brake master cylinder going to the rear brake caliper.

Good Luck
Steve

Your rear brake pedal operates the rear caliper and the front disc. When you tried to bleed the left front caliper you let air into the rear brake system. Bleed the rear brake and front left caliper using the rear brake pedal that should restore the rear (and front) brakes.

It is a hydraulic in line pressure switch that seem to go bad often on the triumph. Check the assembly on end of the of the rod that runs from the rear of the rear brake pedal up into the rear brake cylinder. If the nut has worked its way down, then the pressure could be constant enough to make the contact stay on.
Turn the lights on and work the break pedal up and down with your hand to see if it goes off. If it does not, take the pedal off and see if an adjustment to rod assembly makes the brake light go off.

Good luck, i hope this helps.

the master cylinder could be defective or the proportioning valve is stuck. You can try slamming the brake pedal down at a stop. this may reset the valve, if it goes off thats your problem. if it continues to stay on pull the E Brake or parking brake see if the pedal rises up f the pedal comes up it may mean your rear shoes are worn and the wheel cylinder or caliper seal is leaking. to test if all brakes are working go about 10 mph Be sure you e brake works then hit the brakes once you stop get out and look if there is rubber on the ground on all four wheels. do this in a area where it's safe and you can come to a atop before hitting someone Else's property or going over a cliff. If the front brakes work then your rear are not working if there is no marks on front that means there is a problem with the front brake system. remember the light is a warning jamming down the brakes may cause the master cylinder to fail so be sure your mechanicl emergency brake works good before doing test. otherwise you may experince the pucker factor, one guy at a shop I worked for pushed his tool box ouy yhr tindoor he didn't check the e-brake before doing the test in front of the shop. Opps.

did you change the front, back or both. if it was just the front then you need to put new back brakes in because that's were most of your brake pedal feel comes from. if it was both i would start looking at your brake system to see were the rear brake adjustment valve is and then start fiddling with it till it feels better.

Hi Robert!

When bleeding the fronts and the pedal does not go down all the way, stand on the pedal HARD and see if it won't go down then...

The proper sequence is to bleed fronts FIRST... if you had done this, you probably could have avoided this problem... but no worry, it is just a nuisance!

If you still have a problem after trying this, you might have a master cylinder problem... the seals to the fronts might be leaking, not able to build pressure...

So try this and let me know how it goes, and DON't FORGET: Your rating is my ONLY compensation for helping you!

Thanks!
WildBill