Brake Hose/Line: Service and Repair
STANDARD PROCEDURE - BRAKE TUBE REPAIROnly double wall 4.75mm (3/16 inch) steel tubing with the correct tube nuts are to be used for replacement of a hydraulic brake tube.
Care should be taken when repairing brake tubing, to be sure the proper bending and flaring tools and procedures are used, to avoid kinking. Do not route the tubes against sharp edges, moving components or into hot areas. All tubes should be properly attached with recommended retaining clips.
1. Using a brake tubing cutter, cut off the damaged seat or tubing.
Tube End Properly Prepared For Flaring:
2. Ream out any burrs or rough edges showing on inside of tubing . This will make the ends of tubing square and ensure better seating of flared end tubing.
3. Place the tube nut on the tubing before flaring the tubing. The tubing is now prepped for flaring.
DOUBLE INVERTED FLARES
NOTE: Place the tube nut on the tubing before flaring the tubing. It cannot be installed after the flare is made.
Use Flaring Tool Kit, Special Tool C-4254 or equivalent, to perform the following procedure.
1. Loosen the wing nuts on the tool flaring bar and insert the tubing from the bottom through the correct size hole (4.75 mm [3/16 inch]) in the bar. Extend the tubing beyond the surface of the flaring bar to the proper distance as determined by placing the corresponding size flare adapter flat surface down alongside the tubing, so the end of the tubing is flush with the small step on the adapter.
2. Tighten the wing nuts securely starting with the wing nut closest to the tubing. Make sure the flaring bar holds the tubing tight enough so that it won't slip down during flaring.
3. Insert the stem of the flare adapter down into the end of the tubing.
4. Place the flaring yoke over the flaring bar and adapter, so that the screw flaring tip enters the depression in the center of the adapter while the fingers of the yoke grasp the underside of the flare bar.
5. Using the sliding handle inserted through hole in the top of the yokes screw, tighten the screw, forcing the flaring tip and adapter down until the adapter rests flat against the top of the flaring bar.
6. Back off the screw and remove the flaring adapter. The tubing is now formed into a bell shape, ready for final flaring.
7. Turn the screw and flaring tip down against the center hole of the bell shaped tubing.
8. Tighten the screw, folding the tubing metal in on itself, creating the double inverted flare.
9. Loosen the screw and remove the flaring yoke.
10. Loosen the wing nuts and remove the newly flared tube from the flaring bar.
Double Inverted Brake Tube Flare:
The flare should look like the ones shown in the figures. If it does not, the flare will need to be cut off the tubing and then reformed.
ISO FLARES
CAUTION: All ISO style tubing flares are of metric dimensions. When performing any service procedures on vehicles using ISO style tubing flares, metric size tubing of 4.75 mm MUST be used with metric ISO tube flaring equipment.
NOTE: Place the tube nut on the tubing before flaring the tubing. It cannot be installed after the flare is made.
To create a (metric) ISO style tubing flare, Use Snap-On Flaring Tool TFM-428, or equivalent. Proceed with the steps listed below.
1. Open the jaws of the flaring bar assembly. Align the mating size jaws of the flaring tool around the size of the tubing to be flared.
2. Close the jaws of the flaring bar assembly around the tubing to keep it from sliding out. Position the tube in the jaws of the bar so that it is flush with the top surface of the flaring bar assembly. Tighten the flaring bar assembly.
3. Install the correct size adapter for the brake tubing being flared, on the feed screw of the yoke assembly.
4. Apply lubricant to the adapter area that contacts brake tubing.
5. Center the yoke and adapter over the end of the tubing making sure the adapter pilot is fully inserted in the end of the brake tubing.
6. Turn the feed screw of the yoke assembly until the adapter has seated squarely on the surface of the flaring bar assembly.
7. Back off the feed screw and remove the flaring tool from the tube.
8. Loosen the flaring bar assembly and remove the newly (metric) ISO flared tube.