Hi,
The brakes are barely doing anything when brake pedal is fully depressed. Truck is un-drivable. What is the fix to this? likely problems?

 

Low/ no brake fluid. Leaking calipers/cylinders, busted brake line. Master cylinder bad. Lots of things. What have you checked?

 

brake fluid fine, didnt check brake lines adequately enough . I have had symptoms in the recent past of my front left calliper being tight around rotor and starting fires

What would be the most likely issue? probably rare its a "bad" master cylinder right? i dont know. I shall inspect all brake lines tomorrow.

 

You mentioned starting fires, well that is bad and could mean the seals in the caliper got ruined if they cooked and could cause them to leak. If after removing the wheels and inspecting the lines, calipers and wheel cylinders there are no leaks then I would say its your master cyl. If you have leaks then your fluid level should be low. If any of your wheel cylinders leaked and contaminated the shoes or pads you should replace them also. If you pump up the pedal with the engine off and it losses pressure and fades to the floor then the master cyl seals are bad. Did the bakes go out all at once or gradually? Did you work on the brakes and open the lines at any point? Air in the lines not properly bled will cause poor braking. If you have ABS it needs to be cycled when bleeding with a DRB scan tool at the dealer.

 

Here's your sign.....

 

The fires issue was fixed. Thanks for the great info dxloat