1. Assess the Situation:
* How much is broken? Is it just the bolt head snapped off, or is the shaft sheared inside the starter? This significantly impacts the approach.
* Access: How much room do you have to work? Pictures would help determine the best approach.
* What kind of bolt? Is it a standard bolt, or something more specialized?
2. Methods (from least to most destructive):
* Penetrating Oil: This is your first step *always*. Liberally apply a penetrating oil like PB Blaster, Kroil, or Liquid Wrench to the broken bolt. Let it soak for at least 30 minutes, preferably overnight. Reapply several times.
* Left-Hand Drill Bit: If the broken bolt is sticking up even slightly, you might be able to use a left-hand drill bit. This type of bit will work *into* the broken bolt, potentially backing it out. Use a bit slightly smaller than the bolt diameter. Go slowly, and use plenty of cutting oil. This is only effective if there's enough of the bolt sticking out to get a grip.
* Easy-Outs/Bolt Extractors: These are specialized tools designed for removing broken bolts. They're essentially reverse-threaded drill bits that grab onto the broken bolt. You drill a pilot hole into the broken bolt (smaller than the extractor's threads), then screw the extractor into the hole, working it out carefully. There are different types (left-handed, right-handed, etc.) so choose the correct one based on the situation. This method requires some precision and can be tricky if the bolt is severely broken or the metal is hard.
* Welding: If some of the broken bolt is still protruding, you can weld a nut onto the remaining bolt stub. This provides something to grip with a wrench. You'll need a good welder and some skill for this. Make sure you use the correct welding rod for the bolt material.
* Drilling and Tapping: If all else fails, you may need to drill out the broken bolt completely. This requires precision to avoid damaging the starter casing. Once drilled out, you can then tap the hole to the correct size and thread in a replacement bolt. This is the most destructive option, and requires proper tools and skills. It's probably best left to a machinist if you're not experienced.
3. Specific Considerations for a Starter:
* Starter Removal: You might find it easier to remove the entire starter before attempting to extract the broken bolt. This provides better access and allows for more stable working conditions. Refer to a repair manual for your specific truck model.
* Damage to the Starter: Be very careful not to damage the starter housing or internal components during the extraction process.
* Replacement Bolt: Once you have removed the broken bolt, make sure to replace it with a bolt of the correct size, material, and grade.
Recommendation:
Start with penetrating oil and the left-handed drill bit (if applicable). If those fail, consider using bolt extractors. Welding and drilling are more advanced techniques that require skill and the right tools, and could easily damage the starter if not done correctly. If you're not comfortable performing this yourself, taking it to a mechanic is always an option. They'll have the right tools and experience to handle the job safely and effectively.
