Jeep CJ5 Distributor Cap: A Guide for 1959-1970 Models
Keep your classic CJ5's ignition system reliable with the right distributor cap.
- A failing distributor cap is a common cause of misfires, hard starting, and stalling on a 1959-1970 CJ5.
- This is a simple, low-cost DIY job. Always replace the rotor at the same time as the cap.
- Choose aftermarket caps with brass terminals for better performance and longevity over aluminum.
- Crown Automotive, Omix-Ada, and Standard Ignition are all reputable aftermarket brands for this part.
Is Your CJ5's Distributor Cap Failing?
On a classic Jeep, the distributor cap lives in a hot, demanding environment. Over decades, the plastic can become brittle and crack, and the metal terminals inside can corrode or wear out. These issues can cause a range of frustrating engine problems. Because these Jeeps have simple ignition systems, a bad cap is a common source of trouble.
Key Symptoms of a Bad Distributor Cap:
- Engine Misfires: The engine may sputter or run unevenly, especially under load.
- Hard Starting: The engine cranks but takes a long time to start, or fails to start at all.
- Stalling, Especially When Wet: A cracked cap can let in moisture from rain or puddles, causing the engine to die suddenly.
- Rough Idle: An inconsistent spark can make the engine idle poorly.
- Visible Damage: Check for cracks, moisture inside the cap, white or green corrosion on the terminals, or black carbon tracks between terminals.
Pro Tip: Check the Rotor and Wires
When you replace your distributor cap, it's the perfect time to also replace the distributor rotor. The rotor is the part that spins inside the cap. They wear out together. Also, inspect your spark plug wires for cracks or corrosion.
Choosing the Right Aftermarket Distributor Cap
For a 1959-1970 CJ5, new parts from the original manufacturer are no longer made. The market is served by aftermarket companies, and quality can vary. Look for caps made from high-quality, high-dielectric strength plastic and, if possible, with brass terminals instead of aluminum. Brass offers better conductivity and corrosion resistance.
Aftermarket Brand Tiers
- Standard Ignition (Standard Motor Products): Often considered a top-tier aftermarket brand for ignition components. They have a long history of making quality parts that meet or exceed original specifications. Their caps are often made with superior materials for durability.
- Crown Automotive: A very popular and reputable brand specializing in Jeep parts. They are a go-to choice for many Jeep owners for restoration and repair, offering a good balance of quality and price.
- Omix-Ada: Another major supplier of Jeep-specific parts. They provide a wide range of components and are generally considered a reliable option for keeping a classic CJ5 on the road.
A Note on Fitment
While most parts are direct-fit, always double-check that the cap you're buying matches your Jeep's specific engine (4-cylinder, V6) and distributor type. Some Jeeps of this era may have had their original distributors swapped out over the years. Look at your old cap to confirm the style (e.g., clip-on or screw-on) and terminal type.
Distributor Cap Replacement Cost
Replacing the distributor cap is an inexpensive and straightforward job you can do yourself. The main cost is the part itself.
| Item | Estimated Cost |
|---|---|
| New Aftermarket Distributor Cap | $23.00 - $58.00 |
| Shop Labor | $50 - $100 |
Frequently Asked Questions
How do I replace the distributor cap on my CJ5?
It's a simple job. First, disconnect the battery. Then, one by one, move each spark plug wire from the old cap to the new cap, making sure they go in the exact same position. This keeps the firing order correct. Once the wires are transferred, unclip or unscrew the old cap, remove it, inspect the rotor (and replace it), then install the new cap. Reconnect the battery and start the engine.
Are there any recalls on the 1959-1970 CJ5 distributor cap?
No. There are no active recalls or Technical Service Bulletins (TSBs) from NHTSA for the distributor cap on this vehicle. This is normal for a vehicle of this age.
Should I choose a cap with brass or aluminum terminals?
If available, choose a cap with brass terminals. Brass is a better conductor and is more resistant to corrosion than aluminum, which can lead to a more reliable spark and a longer-lasting part.
What causes a distributor cap to fail?
Failure is usually due to age and environment. Constant high voltage, engine heat, and exposure to moisture eventually break down the plastic and wear out the metal contacts inside. A loose-fitting cap can also allow moisture and dirt inside, which speeds up failure.
Technical Specifications
Varies by engine (4-cylinder or V6) and specific distributor model. Most use a clamp-down attachment style with female/socket plug wire terminals. Terminal material can be aluminum or brass.
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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.