Ford LTD II Alternator Replacement Guide (1977-1979)
Keep your classic Ford's charging system reliable with the right new alternator.
- Your 1977-1979 LTD II uses an externally regulated Ford 1G alternator; replacing the separate voltage regulator at the same time is highly recommended.
- Decide between a direct-fit stock replacement (60-70 amps) or a high-output one-wire upgrade (100+ amps) if you have modern accessories.
- Symptoms like dimming lights, a whining noise, or a recurring dead battery are classic signs of a failing alternator.
- This is a straightforward DIY replacement for most owners with basic tools, typically taking about an hour.
Is Your Alternator Failing?
An alternator rarely fails without warning. If you notice any of these signs on your LTD II, it's time to inspect the charging system. Ignoring them can leave you stranded with a dead battery.
- Dimming or Flickering Lights: Headlights and dash lights may dim at idle and brighten when you rev the engine.
- Battery Light: The 'ALT' or battery-shaped warning light on your dashboard may flicker or stay on.
- Whining or Grinding Noises: A high-pitched whine that changes with engine speed or a grinding sound can indicate failing alternator bearings.
- Weak or Dead Battery: A bad alternator can't recharge the battery, leading to frequent jump-starts or a car that won't start at all.
- Electrical Problems: Slow power windows or a radio that cuts out are signs the alternator isn't providing enough power.
- Burning Smell: A scent of burning rubber or hot wires can point to an overheating alternator or a slipping belt.
Choosing the Right Aftermarket Alternator
For a vehicle from the 1970s, a new aftermarket alternator is often a better and more reliable choice than a rebuilt original or a used part. Original Motorcraft parts are no longer in production, so a new unit from a reputable brand is the modern standard. Your LTD II originally came with a Ford 1G alternator that uses an external voltage regulator. You have two main choices for replacement:
1. Stock-Style Replacement (Externally Regulated)
This is a direct, bolt-in replacement that works with your car's original external voltage regulator. It's the simplest option if you want to keep the factory setup. Standard output is typically 60-70 amps, which is fine for a stock vehicle.
2. One-Wire Upgrade (Internally Regulated)
Many modern replacements are "one-wire" alternators with a built-in internal regulator. These are a popular upgrade, especially if you've added electrical accessories like a modern stereo or brighter headlights. They offer higher amperage (100+ amps) and simplify the engine bay by allowing you to bypass the old external regulator. Brands like Proform specialize in these high-output, easy-to-install units.
Aftermarket Brand Tiers
| Tier | Brands | Notes |
|---|---|---|
| Standard Replacement | WAI Global, BBB Industries, Remy, USA Industries | These brands offer reliable, new or quality-remanufactured units that meet or exceed original specifications. WAI Global is often noted for providing 100% new units. |
| Performance/Upgrade | Proform, Powermaster | Known for high-output, one-wire alternators that are great for cars with extra electrical demands. Often available in chrome or other custom finishes. |
Cost of a New Aftermarket Alternator (1977-1979 Ford LTD II)
| Part Type | Estimated Cost |
|---|---|
| New Aftermarket Alternator | $40 - $281 |
| Shop Labor | $100 - $200 |
Frequently Asked Questions
Do I need a high-output alternator?
If your LTD II is stock with its original radio and lights, a standard 60-70 amp alternator is sufficient. If you have added a powerful sound system, electric fans, or modern lighting, a high-output alternator (100+ amps) is highly recommended to handle the extra load.
What is an external voltage regulator and should I replace it?
It's a small box, usually mounted on the fender wall, that controls the alternator's output to prevent it from overcharging the battery. These are a known weak point in older Ford charging systems. It is highly recommended to replace it when you replace the alternator, as a faulty regulator can damage a new alternator.
Can I install the alternator myself?
Yes, this is a very DIY-friendly job for a home mechanic. The alternator is typically easy to access on top of the engine. The process involves disconnecting the battery, loosening the drive belt, removing a few wires and bolts, and then reversing the steps.
What are common mistakes when ordering?
The most common mistake is not knowing if you need an externally regulated or internally regulated (one-wire) alternator. Check your current setup. Also, ensure the pulley type (V-belt) matches your car's belts. While the same basic alternator fits all V8 engines for this car, confirming the mounting style and pulley is always a good idea.
Technical Specifications
OEM Part Numbers: D7AZ-10346-A D9VY-10346-A D7AF-10300-CA D2TZ-10346-BA
Type: Ford 1G Voltage: 12V Regulation: External Standard Amperage: 60-70 Amps Pulley: Single V-Groove
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The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- 🛍️ Shop This Part
- Is Your Alternator Failing?
- Choosing the Right Aftermarket Alternator
- 1. Stock-Style Replacement (Externally Regulated)
- 2. One-Wire Upgrade (Internally Regulated)
- Aftermarket Brand Tiers
- Cost of a New Aftermarket Alternator (1977-1979 Ford LTD II)
- Frequently Asked Questions
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