A Practical Guide to Universal Joints for the 1971-1977 Mercury Comet
Keep your classic Comet's driveline smooth and reliable by understanding its universal joints.
- A clunking noise when shifting or a vibration while driving are the most common signs of a bad U-joint on your Comet.
- Do not ignore symptoms, as a complete failure can cause the driveshaft to drop, leading to a dangerous situation and costly repairs.
- High-quality aftermarket brands like Dana Spicer and Moog offer replacements that are as good or better than the original 1970s parts.
- Your Comet has two U-joints; it's best to measure them before ordering and replace them at the same time.
Is Your Comet Making a Strange Noise or Vibration?
On a car as old as a 1971-1977 Mercury Comet, parts wear out. U-joints are a common wear item. Because they are always moving and under a lot of stress, they eventually fail from normal use or lack of lubrication. When a U-joint starts to go bad, your car will give you clear warning signs. Ignoring them can lead to the driveshaft disconnecting from the car, which is dangerous and can cause a lot of expensive damage.
Common Symptoms of a Bad U-Joint
- Clunking Noise: A loud "clunk" or "bang" when you shift from Park into Drive or Reverse is a classic sign. This sound comes from too much play in the worn-out joint.
- Vibrations: You might feel a vibration throughout the car that gets worse as you drive faster. This is often confused with an out-of-balance tire, but it's caused by the driveshaft spinning unevenly with a bad U-joint.
- Squeaking or Chirping: A rhythmic squeaking noise that matches your speed, especially at lower speeds, usually means the U-joint is dry and needs lubrication or replacement.
- Visible Rust or Leaks: If you look under the car, you might see rust-colored dust around the U-joint's bearing caps. This is a sign that moisture has gotten inside and the joint is failing.
Choosing the Right Aftermarket U-Joint
Since your Comet is a classic, new original equipment (OEM) parts from Mercury are no longer available. All new U-joints you buy will be aftermarket. The good news is that many aftermarket brands meet or exceed the quality of the parts made in the 1970s. Your Comet likely uses two U-joints, one at the front of the driveshaft and one at the rear. Some owners on forums for the Comet and its sister car, the Ford Maverick, note that different engine and axle combinations can sometimes use different size U-joints, so it's wise to measure your old parts before ordering.
Brand Quality Tiers
Here’s a breakdown of the available brands, from good to best, to help you choose.
- Good (Economy): GMB is a well-known Japanese manufacturer that offers a budget-friendly option. They are generally considered a decent replacement for a standard daily driver and reviews show they fit and work fine for most users. However, some long-time mechanics have noted a decline in quality over the years.
- Better (Standard): Moog and SKF are strong, reputable aftermarket brands. Moog is a very common choice and offers features like grease fittings for easier maintenance. SKF is a global leader in bearings and driveline components, and their quality is well-regarded. For most Comet owners, parts from these brands offer a great balance of price and quality.
- Best (Premium/Performance): Dana Spicer is often the original manufacturer for many American cars and is considered a top-tier choice. Their non-greasable, solid-body U-joints are often considered the strongest and most durable option. Yukon Gear & Axle is another premium brand, specializing in high-performance drivetrain parts. While it might be more than a stock Comet needs, their quality is excellent.
Many aftermarket U-joints, like those from Moog, come with a grease fitting (zerk) that allows you to add fresh grease periodically. This can extend their life if you do regular maintenance. Non-greasable (or sealed) joints, like many from Spicer, are filled with high-quality grease at the factory and sealed for life. Many experts believe these sealed joints are stronger because the cross isn't hollowed out for a grease channel, and they often last longer than greasable joints that aren't regularly maintained.
Cost to Replace a Mercury Comet U-Joint
The cost is broken down into the part itself and the labor to install it. The parts are inexpensive, but labor can vary.
| Item | Estimated Cost |
|---|---|
| New Aftermarket U-Joint (per joint) | $19.18 - $107.89 |
| Shop Labor | $150 - $300 |
| Total (One Joint) | $170 - $408 |
Note: Your Comet has two U-joints. It is recommended to replace them in pairs. Prices are estimates and will vary by location and shop.
Frequently Asked Questions
How many U-joints does my 1971-1977 Mercury Comet have?
A standard Mercury Comet has two universal joints on its single driveshaft: one at the front connecting to the transmission and one at the rear connecting to the differential.
Are the front and rear U-joints the same?
Sometimes they are, but not always. Depending on the engine, transmission, and rear axle combination your car has, it could use two different sizes. Some owners have found they needed a "conversion" U-joint with two different cap sizes. It is always best to measure your old U-joints (cap diameter and overall width) before ordering replacements.
Can I replace a U-joint myself?
Yes, it is possible for a DIY mechanic. However, it requires safely lifting the vehicle, removing the driveshaft, and using either a large bench vise with sockets or a special U-joint press to push the old joints out and press the new ones in without damaging the bearing caps. Using a hammer can damage the driveshaft yoke. If you are not comfortable with this, it is a fairly quick job for a professional mechanic.
Were there any recalls for the Mercury Comet U-joint?
There are no recalls or common Technical Service Bulletins (TSBs) on file with the National Highway Traffic Safety Administration (NHTSA) for universal joint failures on the 1971-1977 Mercury Comet. Any failures today are due to the age and wear of the original or replacement parts.
Technical Specifications
The most common U-joint series for this vehicle is the 1310 series. However, different drivetrain combinations may exist. It is critical to measure the bearing cap diameter and cross width of the existing U-joints before purchasing replacements to ensure a correct fit.
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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.