Replacing the timing belt on a classic 1968 Ford Mustang GT Fastback (Bullitt) is an essential maintenance task that can help ensure the engine runs smoothly and efficiently. Over time, the timing belt can wear out or even break, which can severely affect engine performance and potentially cause further damage. If you notice unusual noises from the engine bay, performance issues, or see visible signs of wear on the belt, it's time to replace it. Here is how to solve this issue.

Step 1: Gather Necessary Tools and Parts
First, you will need a replacement timing belt, a socket set, a timing light, a torque wrench, and possibly a harmonic balancer puller. Ensure you have the vehicle’s manual for reference.

Step 2: Prep the Vehicle
Park the car on a flat surface, set the parking brake, and disconnect the battery to ensure safety. Open the hood to access the engine bay.

Step 3: Locate the Timing Belt Cover
The timing belt cover is located at the front of the engine. It's usually a plastic or metal cover that may have bolts or screws securing it. You may need to remove other components or belts to access the cover, so keep an eye out for any obstructions.

Step 4: Remove the Timing Belt Cover
Remove the bolts or screws holding the timing belt cover in place using your socket set. Carefully remove the cover, taking care not to damage it or surrounding components.

Step 5: Align Timing Marks
Before removing the old belt, you need to align the timing marks on the crankshaft and camshaft. This ensures that the engine timing remains correct when you install the new belt. Use a timing light to help with this step. The timing marks are usually visible on the gears and should line up with corresponding marks on the engine block.

Step 6: Remove the Old Timing Belt
Loosen the tensioner pulley that keeps the timing belt tight. This will allow you to remove the belt easily. Carefully slide the old belt off the gears. If you need more room, you may have to remove the harmonic balancer using a puller.

Step 7: Install the New Timing Belt
Carefully place the new timing belt onto the gears, ensuring the timing marks remain aligned. Double-check the alignment before proceeding. Tighten the tensioner pulley to make sure the belt is properly tensioned.

Step 8: Reassemble the Engine
Reattach any parts you removed earlier, including the harmonic balancer if applicable. Replace the timing belt cover and secure it with the bolts or screws.

Step 9: Reconnect the Battery and Test
Reconnect the car’s battery. Start the engine and observe for any unusual noises or performance issues. Use the timing light to verify that the engine timing is accurate.

Step 10: Final Inspection
Shut off the engine and do a final inspection to ensure everything is securely in place and there are no loose components.

By following these steps, you help ensure your 1968 Ford Mustang GT Fastback (Bullitt) remains in top condition. Proper maintenance not only extends the lifespan of your classic car but also provides a smoother and more reliable driving experience.