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Clark's Garage944 · 924 · 968 · Turbo
Reference

Allen Head and Cheesehead Bolt Removal

Technique for removing stubborn Allen head and cheesehead bolts from aluminum engine components on the Porsche 944, where steel bolt threads can bond to the aluminum over time.

Difficulty: Easy1 min readApplies to: 944 · 944S · 944S2 · 944 Turbo · 968
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Introduction

Allen head and cheesehead bolts can be extremely difficult to remove from 944 engines. Because most of the 944 engine is aluminum, steel bolt threads tend to bond to the surrounding aluminum over time. Nearly anyone who has worked on a 944 engine has stripped an Allen head or cheesehead bolt at some point.

"Waking Up" the Bolts

Before attempting to break a stubborn bolt free, use percussion to break the bond between the bolt and the aluminum:

  1. Using a punch or socket extension and a hammer, tap around the outside of the bolt head.
  2. For Allen head bolts, also tap a punch on the inside of the Allen head opening.
  3. While attempting to remove the bolt, keep the Allen head tool or cheesehead socket inserted straight into the bolt head. This requires two hands — one to hold the tool straight and the other to turn it.
  4. If the bolt does not break free easily, tap the head again before retrying.
Tags:boltsfastenersallen headcheeseheadaluminumstripped boltengine

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