To repair a stuck solenoid, remove the ignition wires, main starter, large starter mounting bolts, starter twist, and small ball and spring; remove the studs; mount the new copper contacts; and load the old spring and ball before fitting the plunger into the solenoid. Next, mount the solenoid plate, secure the thick wire to the solenoid, and put back the mounting bolts.
Park the vehicle with the emergency brake set. Uplift the bonnet, detach the negative terminal of the battery, and raise the vehicle to a height that fits two jack stands under each wheel.
Remove the two ignition wires and the main starter wire located at the back of the solenoid from under the vehicle. Study the proper location of the wires before installation. Using a proper socket, pull out the large starter mounting bolts. Remove the starter twist by turning it round until it's off its mounting position. Detach the thick wire that attaches the starter to the solenoid post.
Check the position of the small ball and the spring on the plunger before removing them. Remove the studs that bring the two copper contacts into place. Mount the new copper contact, and fix the studs firmly. Load the old spring and the ball onto the new plunger. Holding the tension on the spring, fit the plunger into the solenoid.
Align the spring and ball, mount the solenoid plate, and tighten the spring and ball in the solenoid. Connect the thick wire to the solenoid, and secure it firmly. Put the starter in the right position from under the vehicle. Put back the mounting bolts, and ensure they're well-secured.
Put the main starter wire and the ignition wire back to their positions, and tighten them as well. Finally, remove the jack stand, and connect the negative terminal.