A Guide to Universal Joints for the 1973-1980 Jaguar XJ12
Understanding the critical role of the U-joints in your Jaguar's unique rear suspension is key to keeping it on the road.
- The four rear U-joints are also critical suspension components; their failure is a major safety risk.
- Symptoms include clunking noises when shifting, vibrations at speed, and squeaking sounds.
- Replacement, especially for the rear joints, is a difficult job best left to a professional mechanic familiar with Jaguars.
- For reliability and safety, use premium aftermarket brands like Dana Spicer or SKF.
Understanding U-Joints on Your XJ12
The universal joints on your 1973-1980 Jaguar XJ12 are essential for a smooth, safe ride. A U-joint is a cross-shaped part with four bearing caps that allows the driveshaft to spin without binding as the suspension moves. Your car has several: at least two on the main propshaft (driveshaft) and four on the rear axle half-shafts (two per side). The rear U-joints are especially important because they are a load-bearing part of the rear suspension. If one fails, it can affect your car's handling and safety.
Symptoms of a Failing Universal Joint
Worn U-joints give several warning signs. Ignoring them can lead to more damage or a driveshaft failure. Listen and feel for these common symptoms:
- Clunking Noise: A loud 'clunk' or 'clack' when you shift into Drive or Reverse is a classic sign of a worn U-joint with too much play.
- Vibration: You may feel a vibration through the floor of the car, often at a specific speed range (like 30-40 mph) that goes away as you go faster or slower.
- Squeaking or Rattling: A persistent, metallic squeak that changes with speed can point to a dry, failing U-joint that has lost its lubrication.
- Visible Rust Dust: If you see fine, reddish-brown dust around a U-joint's bearing caps, it's a sign that the internal needle bearings are wearing out and creating rust.
A Critical Safety Note for XJ12 Owners
The rear axle shafts on your Jaguar are also the upper control arms for the rear suspension. A failure of one of the four rear U-joints is not just a driveline problem—it is a suspension failure. This can cause a loss of vehicle control. Any suspected rear U-joint issue should be inspected immediately.
Choosing the Right Aftermarket U-Joint
Original Jaguar U-joints for this era are rare. The market is served by quality aftermarket brands. Your choice depends on your budget and how you use the car. Forum discussions among classic Jaguar owners show a clear preference for quality.
| Brand Tier | Brands | Assessment |
|---|---|---|
| Premium Quality | Dana Spicer Chassis, SKF | Dana Spicer is widely regarded as the top choice, often exceeding original quality. They are known for durability and are a favorite in the classic car community. SKF is a world-renowned bearing manufacturer, and their U-joints are considered a high-quality, reliable option. |
| Standard / Mid-Grade | Moog | Moog was once a top-tier brand, but recent owner feedback is mixed. Some find them reliable, while others report a decline in quality. They can be a decent choice, but quality may be inconsistent compared to Dana Spicer. |
| Economy | GMB | GMB is a budget-friendly option that meets basic specifications. While suitable for a car that is driven lightly, most Jaguar specialists recommend using a premium brand for the critical rear suspension U-joints. |
Greasable vs. Sealed U-Joints
You will see options for both greasable (with a zerk fitting) and sealed (non-greasable) U-joints. Sealed joints are generally stronger because the cross is solid metal. Greasable joints can have a longer life if you are diligent about lubricating them every 12,000 miles. For most owners, a high-quality sealed joint from a brand like Spicer is a reliable, maintenance-free choice.
Frequently Asked Questions (FAQ)
How many U-joints does my 1973-1980 XJ12 have?
Your car has a total of six universal joints. There are two on the main driveshaft (propshaft) and four on the rear axle half-shafts (one at the inner end and one at the outer end of each shaft).
Can I replace just one bad U-joint?
Yes, but it is highly recommended to replace them in pairs. For example, if one U-joint on a rear half-shaft is bad, you should replace both on that shaft. Since the labor is intensive, many owners choose to replace all six U-joints at once for long-term peace of mind.
Why is replacing the rear U-joints so difficult?
Because the rear axle half-shafts are part of the suspension, they cannot be simply unbolted. The job requires removing the wheels, disconnecting the lower shock bolts, unbolting the shaft from the differential, and often using a special puller to press the shaft out of the wheel hub. It is a labor-intensive job.
Are there any recalls for the U-joints on my XJ12?
No. Searches of the National Highway Traffic Safety Administration (NHTSA) database show no recalls or technical service bulletins (TSBs) related to universal joints for the 1973-1980 Jaguar XJ12.
Technical Specifications
Verify fitment before ordering. The Spicer 5-153X is a commonly referenced part number for the main driveshaft on similar era Jaguars, but always check against your specific vehicle's requirements.
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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.