1994-1996 Infiniti Q45 Struts: Standard vs. Active Suspension and Finding Parts

Identifying Your Suspension: Standard vs. Full-Active (FAS)

Before diagnosing or buying parts for your 1994-1996 Q45, you must first determine which suspension system it has. This is the single most important step, as the parts are completely different and not interchangeable.

• Standard Suspension: Most Q45s were equipped with a conventional suspension system using standard struts and coil springs. These are passive components that are serviceable with readily available mounts and, with some difficulty, replacement struts.
• Full-Active Suspension (FAS): A rare and expensive option, FAS was a groundbreaking hydraulic system designed to eliminate body roll, dive, and squat. It used a complex network of sensors, a computer, and hydraulic actuators at each corner. These cars were designated with a 'Q45a' badge. While technologically advanced for its time, the system is prone to leaks and component failure, and repairs are prohibitively expensive. Many Q45a models have since been converted to standard coilover suspension by previous owners.

Symptoms of a Failing Strut

Worn struts compromise both ride comfort and safety. Because the wear happens gradually, you may not notice the degradation until it becomes severe. Look for these common signs:

• Bouncy, Floating Ride: The most common symptom is excessive bouncing after hitting a bump. The car may feel unstable or 'floaty' at highway speeds.
• Clunking or Knocking Noises: A metallic clunking or knocking sound when driving over bumps indicates the internal components of the strut are worn, causing metal-on-metal contact. Creaking or groaning can also point to worn suspension bushings, a common issue on the Q45.
• Nose-Diving and Squatting: If the front end of the car dives excessively when you brake hard, or the rear end squats during acceleration, the struts are no longer able to control the vehicle's weight transfer.
• Visible Fluid Leaks: The strut body is filled with hydraulic oil. If you see oily, wet residue on the outside of the strut, its seals have failed and it needs immediate replacement. Note that Infiniti considers a very slight, thin film of oil to be normal seepage, but any thick oil or drips that run down the strut body indicate failure.
• Unusual Tire Wear: When struts are bad, the tires can bounce slightly as you drive, leading to a scalloped or 'cupped' wear pattern on the tread.
• Clicking When Turning: A clicking or growling noise that occurs only when turning the steering wheel often points to a failed bearing in the upper strut mount, not the strut itself.

Buying a Used OEM Strut: Your Best Option

Finding new struts for the 1994-1996 Q45 is extremely difficult and expensive. New OEM units are often discontinued or cost over $500 each, and direct-fit aftermarket options are scarce. For most owners, a low-mileage used OEM strut is the most practical and affordable solution.

What to Inspect:

• Check for Leaks: This is the number one red flag. Do not buy a strut that has any sign of thick, oily fluid on its body. The exterior should be dry.
• Inspect the Rod: The polished chrome rod that extends from the top of the strut should be smooth and free of rust, pitting, or damage. Any imperfections will quickly destroy the new seal and cause it to leak.
• Verify Mileage: Struts are a wear item, typically lasting between 50,000 and 100,000 miles. Always choose a part from the lowest-mileage donor vehicle available.
• Confirm Compatibility: Double-check that the strut came from a 1994-1996 Q45 with the standard suspension. Front struts from 1990-1993 models have a different lower mounting diameter and will not fit without modification. Rear struts are reportedly the same for all 1990-1996 models. Absolutely avoid parts from a Q45a unless you are repairing an active suspension system.
• Buy in Pairs: It is essential to replace struts in pairs (both fronts or both rears) to ensure balanced handling and predictable performance. Mismatched struts can make the car unstable.

Known Issues and Part Scarcity

The biggest challenge for 1994-1996 Q45 owners is the lack of available replacement struts. Many online retailers list parts that are not actually in stock. This has led some expert DIY-ers to modify struts from the 1990-1993 Q45. This involves having a machine shop drill out the lower mounting collar to fit the larger bolt used on the '94-'96 models. This is an advanced repair and should not be attempted without professional help.

Additionally, the front suspension is known for wear on other components like upper control arm bushings and tension rod bushings, which can cause creaking noises and should be inspected when replacing the struts.

Cost Comparison for Strut Replacement (Per Pair)

Replacement Procedure Overview

Replacing a strut is a job for an experienced DIYer or a professional shop. It requires specialized tools, including a spring compressor, which can be very dangerous if used incorrectly.

1. The vehicle is lifted and the wheel is removed.
2. The brake caliper, sway bar end link, and any sensors are detached from the strut housing.
3. The large lower bolts connecting the strut to the steering knuckle are removed.
4. The smaller nuts holding the top of the strut mount to the car's body in the engine bay or trunk are removed.
5. The entire strut assembly can now be removed from the vehicle.
6. CRITICAL STEP: If you are only replacing the strut cartridge and reusing your spring, a spring compressor must be used to safely compress the spring before removing the large center nut on the top mount. Failure to do so can result in the spring releasing with explosive force.
7. Installation is the reverse of removal. All bolts must be torqued to factory specifications.

Frequently Asked Questions (FAQ)