How do i take off bottom garage door section , it has brackets with cables attached to the bottom section ? I understand the cables are under alot of tension andcan harm me so how do I disconnect the bottom panel safely to install a new section of the bottom of the door ?

It should still work for minimal use. If it's a roller other than the bottom two you can just buy one that closely fits and replace by taking the hinge off with a wrench. ONLY WITH THE DOOR CLOSED!! DO NOT REMOVE THE BOTTOM BRACKETS WHERE THE CABLES ARE ATTACHED. YOU'LL LOSE A FINGER OR TWO!!!

Why not just tighten it up? If it is loose, it can get looser and may jam the door causing the torsion spring to break. This situation is unlikely but it could happen

Please do not attempt to set the tension your self. Call a garage door service Co. Broken arms and fingers result. It is not worth the attempt. Those tension spring do all the lifting of the door and have to much torque to mess with.

YOU MAY HAVE A CABLE OFF AT THE DRUM - DO NOT ATTEMPT TO REPAIR THIS IT IS UNDER ALOT OF PRESSURE AND IS TOO DANGEROUS FOR ANYONE EXCEPT A PRO.

DO YOUSELF A FAVOR AND CALL SOMEONE - SHOUL COST LESS THAN $ 100.00 AND YOU WILL STILL HAVE ALL YOUR FINGERS

It's probably in the door itself. (Your reference was to the remote control) Disconnect the door from the operator(pull the red cord) and open and close the door manually. Make sure all of the hinges are tightly screwed to the door. Check the rollers in the track-do they wobble? They have bearings in them, and go bad after a while. My guess is that at least one of the rollers has gone bad; probably one that is in the radius of the track when the problem occurs. Also check where the track connects to itself. Is there a loose connection? Also, lubricate the hinge pivot points, the rollers where the bearing and the shaft come together, the operator(opener) chain, and the springs. DO NOT USE WD40 AS A LUBRICANT it is a de-greaser and will remove the factory grease inside of the rollers. Use 3-in-1 household oil or even motor oil in an oil can with a thumb-pump nozzle. Do remove grease and dirt build up from the track of the door as well as the operator rail. If you have screw-drive operator, use white lithium grease on the screw after cleaning out the old grease that will have metal filings from the screw rail. Clean any spider webs, dirt,etc from your electric eyes with a dry rag. NEVER EVER EVER MESS AROUND WITH THE SPRINGS OR THE BOTTOM FIXTURES WHERE THE LIFT CABLES ARE CONNECTED OR THE PULLEYS WHERE THE LIFT CABLES GO AROUND; THEY ARE UNDER HIGH TENSION AND YOU WILL GET HURT.

Window Regulator, Rear Door, Explorer Removal

1. Remove the rear door trim panel and watershield. Refer to Section 01-05B .

Trim Panel, Rear Door, Explorer, Hi-Series Four-Door Removal and Installation

1. Remove the two screws retaining the rear door trim panel (27406) located above the door handle.

1. Remove trim cup at the door handle using a screwdriver or sharp object. Retention nibs will flex for easy removal.

1. To remove window regulator switch plate (14524) , use notch located at lower end of plate using a screwdriver to lift and remove.

1. Remove window regulator switch plate from rear door trim panel pulling wire harness from rear door trim panel .

1. From bottom of window regulator switch plate , remove two screws and disconnect connector from window regulator control switch (14529) .

1. At each plastic clip location, pry the rear door trim panel away from the door inner panel using the door trim panel removing tool from Rotunda Moulding/Trim Kit 107-00401 or equivalent.

1. Remove panel, lift slightly to remove flange at the top of rear door trim panel from trough in the glass weatherstrip. For installation, follow removal procedures in reverse order. Replace any bent, damaged or missing plastic clips on the rear door trim panel to the door inner panel, firmly loading clips into slots provided on rear door trim panel .
   
   

1. If equipped with power windows, disconnect the wire from the regulator.

1. Remove the rear door window glass as described in this section.

1. Remove the window guide, if equipped, (nuts and washers). Remove guide from door belt opening.

1. Remove three 1/4-inch rivets attaching motor bracket (electric) to inner panel and two 1/4-inch rivets attaching regulator lower bracket to inner panel. Use drift punch to knock out center pins for each rivet. NOTE: Use care not to enlarge sheet metal holes in the door inner panel when drilling.
   

1. Using a 1/4-inch diameter drill, drill out the remainder of the rivet.

1. Remove two upper regulator attaching nuts.

1. Remove regulator from the front door (20125) .

Installation

1. Lubricate regulator mechanism with Multi-Purpose Grease D0AZ-19584-AA or equivalent.

1. Install regulator into access hole in inner panel.

1. Position regulator using upper regulator studs and tabs on motor mounting bracket (electric) or cup mounting plate (manual).

1. Install rivets attaching regulator to door inner panel (1/4-20 x 1/2-inch bolt and 1/4-20 nut and washer assemblies or equivalent metric fasteners may be used as alternates).

1. Install two upper regulator attachment nuts.

1. Install door glass as outlined under Door Glass Installation.

1. Adjust glass as outlined under Adjustments .

1. Reconnect wire to regulator, if equipped.

1. Check operation of window regulator.

1. Install door watershield and trim panel. Refer to Section 01-05B .

pull the rope attached to the garage door opener.  And get a friend to help you lift the door.

Get a roller with a long stem. Then open door fully and clamp open. take off cable. unbolt botton bracket, insert roller into it and track, rebolt, reattach calble, that is it.

i would contact CHI