Mend any holes or tears, stretch the roof liner tight, apply contact cement, clamp into place and trim off any excess liner are the steps for repairing a car roof liner. The process requires a needle and thread, contact cement, a small brush, small clamps or clothespins and a razor. Repairing the roof liner requires a helper to hold the liner in place during repairs.
Inspect the liner for holes or tears and areas where it is sagging. Use a double-threaded needle to sew up any damaged areas. Pull the liner down and sew it from the inside so that the thread seam does not show.
Ventilate the inside of the car by opening all of the doors to disperse the fumes from the adhesive. Be sure to pull the liner tight. Start at the back of the vehicle and use a brush to apply the contact cement directly to the roof in small areas. Press the liner against the coated areas and clamp it into place. Gradually work to the front of the vehicle and trim the loose liner left over from the fresh stretching with a razor.
Let the glue dry for 24 hours with the clamps in place. Remove the clamps and inspect the liner for any loose areas. Reapply cement to any spots that need it.