Allen Head and Cheesehead Bolt Removal – 2.5L NA

Overview

This procedure outlines the steps to safely remove Allen head and Cheesehead bolts on the Porsche 944 with an 8-valve engine configuration. These bolts, often found on the engine, can be challenging to remove due to the bonding of steel bolt threads to the aluminum engine components. This guide provides a technique to loosen these bolts without stripping them, ensuring a smooth repair process. It applies to both pre-1985.5 and 1985.5 onwards models of the Porsche 944 (1983–1988) with an 8-valve engine.

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Tools Required

• Punch (3mm or 1/8 inch)
• Hammer (16 oz or 0.45 kg)
• Socket extension (6mm or 1/4 inch diameter)
• Allen head tool set (5mm to 10mm or 3/16 inch to 3/8 inch)
• Cheesehead socket (specific to Porsche 944, 10mm or 3/8 inch drive)

Step-by-Step Procedure

Step 1: Prepare the Bolt for Removal

1. Locate the Allen head or Cheesehead bolt on the engine that needs to be removed.
2. Using a punch (3mm or 1/8 inch) or a socket extension (6mm or 1/4 inch diameter) and a hammer (16 oz or 0.45 kg), gently tap around the outside edge of the bolt head. This helps to break the bond between the steel bolt threads and the aluminum engine component.

For Allen head bolts:
Additionally, tap inside the Allen head opening with the punch (3mm or 1/8 inch) and hammer (16 oz or 0.45 kg) to further loosen the bolt.

Step 2: Remove the Bolt

3. Select the appropriate tool: a 5mm to 10mm (3/16 inch to 3/8 inch) Allen head tool for Allen head bolts or a Cheesehead socket (10mm or 3/8 inch drive) for Cheesehead bolts.
4. Insert the tool straight into the bolt head, ensuring proper alignment to avoid stripping. Use one hand to hold the tool firmly in place and the other to turn it counterclockwise.
5. Apply steady pressure to loosen the bolt. If the bolt does not break free easily, stop and repeat the tapping process from Step 1 to further loosen it.
6. Once the bolt begins to turn, continue rotating counterclockwise until it is fully removed. Store the bolt in a safe place to avoid loss.

Post Procedure Checklist

• Inspect the removed bolt for signs of stripping or damage to the head or threads. Replace if necessary.
• Check the threaded hole in the engine for debris or damage. Clean with a wire brush if needed.
• Ensure all tools are accounted for and no foreign objects are left on or near the engine.

Sources

• Clark’s Garage
• Porsche 944 Workshop Manual
• Pelican Parts Technical Articles