1985 Bentley Turbo R Rear Suspension Parts: A Complete Guide

The 1985 Bentley Turbo R is a landmark vehicle that combined grand touring luxury with serious performance. However, even the finest British engineering ages, and the rear suspension is one area that demands attention. Understanding the specific parts and maintenance needs of the Turbo R's rear suspension can save you time, money, and headaches. Whether you're restoring a classic or keeping your driver in top shape, this guide covers everything from the air spring system to bushings and shock absorbers.

The 1985 Bentley Turbo R Rear Suspension Design

The rear suspension of the 1985 Turbo R is a sophisticated independent system featuring coil springs, hydraulic self-leveling, and anti-roll bars. Unlike many modern cars, the Turbo R uses a complex arrangement of trailing arms, semi-trailing arms, and a Watt linkage for lateral location. The self-leveling system, borrowed from Rolls-Royce, uses hydraulic struts and a height control valve to maintain ride height regardless of load. This design provided a smooth ride but introduced several components that wear over time.

Key Components of the Rear Suspension

Air Springs and Struts

Factory-equipped with air springs, the Turbo R relies on a pressurized air system to support the vehicle weight and adjust ride height. The air springs are filled via a compressor and a height control valve. Over time, air springs can develop leaks, crack, or fail due to rubber degradation. Symptoms include sagging on one side, hissing sounds, or excessive bouncing. Replacement air springs are available from OEM suppliers like Dunlop or specialized aftermarket brands.

Shock Absorbers

The rear shocks are hydraulic units that control damping. Worn shocks lead to poor ride quality, excessive sway, and reduced tire contact. Many owners switch to aftermarket gas-charged shocks for improved handling without sacrificing comfort. Monroe and Bilstein offer direct-fit replacements that match the original specifications.

Self-Leveling System

This system includes a hydraulic pump, leveling valve, and pipework. The leveling valve is prone to sticking or leaking, causing the rear to sit too high or too low. Rebuilding kits are available, but many owners bypass the system entirely when converting to coil springs. If you want to preserve original functionality, source genuine Rolls-Royce parts or high-quality reproductions.

Bushings and Silent Blocks

The rear suspension uses numerous rubber bushings in the trailing arms, shock mounts, and anti-roll bar links. After 30+ years, these bushings harden, crack, and lose their insulating ability, leading to clunks, vibrations, and imprecise handling. Polyurethane bushings are a popular upgrade for tighter control and longevity, though they transmit more road noise. Rubber OEM-style bushings offer comfort but may need replacement again in a shorter period.

Anti-Roll Bar Links and Bushes

The rear anti-roll bar connects the two trailing arms and reduces body roll. The drop links and bushes wear out, causing clunking noises. Replacing them with upgraded polyurethane components is a common and cost-effective fix.

Wheel Bearings and Hubs

The rear wheel bearings are robust but can fail due to age or water ingress. A humming or grinding sound from the rear indicates bearing wear. Replacement involves pressing out the old bearing and installing a new one. Ensure proper torque to avoid premature failure.

Common Issues with the 1985 Bentley Turbo R Rear Suspension

1. Leaking air springs – The most frequent complaint. Often caused by a crack in the rubber bellows or a failed O-ring at the top or bottom seal.
2. Failed self-leveling valve – Stickiness or internal leaks lead to incorrect ride height. Sometimes a simple cleaning and lubrication of the valve linkage restores function.
3. Worn trailing arm bushings – The large bushings at the chassis end wear out, causing rear axle shift and poor alignment. Clunking over bumps is a telltale sign.
4. Corroded shock mounts – Road salt and moisture can rust the shock tower mounts. Inspect regularly, as rust repair can be expensive.
5. Failed hydraulic pump – The pump that supplies fluid to the self-leveling struts may lose pressure due to internal wear. Rebuilding or replacing the pump is a major job but restores proper function.

Replacement Options: OEM vs. Aftermarket

When sourcing parts, you have three main routes:

• OEM (Original Equipment Manufacturer): Parts from Rolls-Royce or their traditional suppliers (Dunlop, Girling, etc.). These are expensive but offer guaranteed fit and longevity. Ideal for concours restorations.
• OEM-Equivalent: Brands like TRW, Moog, or Lemförder produce direct-fit parts that match original quality at lower prices. These are a good balance for daily drivers.
• Aftermarket Upgrades: Polyurethane bushings, adjustable shocks, or coil spring conversion kits. These can improve handling and longevity but change the car's character. Coil-over conversion eliminates the air system entirely, solving many issues but altering the ride.

Coil Spring Conversion Kits are a popular modification: they replace the air springs and self-leveling system with conventional coil springs and shocks. Benefits include simplicity, lower maintenance, and more predictable handling. Drawbacks include losing the automatic leveling and a slightly harsher ride. Several reputable manufacturers offer complete kits specifically for the 1985 Turbo R.

Step-by-Step Replacement Guidance (Overview)

Note: Working on the Turbo R's rear suspension requires a thorough understanding of high-pressure hydraulics and heavy components. Always use safety stands and follow a workshop manual. Here is a high-level overview:

1. Safety first – Disconnect the battery, relieve hydraulic pressure, and support the vehicle on stands.
2. Remove the wheel and access the suspension components.
3. For air spring replacement: Remove the lower bolt, then carefully depressurize the system before detaching the air line. Replace with new spring and O-rings.
4. For shock replacement: Remove the top and bottom bolts, compress the shock if needed, and install the new unit.
5. Bushing replacement: Use a press or bushing removal tool to push out old bushings and install new ones. Polyurethane bushings often require lubrication.
6. After reassembly, bleed the hydraulic system if the self-leveling is retained. Test for leaks and proper ride height.

Tools needed: Ratchet set, torque wrench, bushing press, jack stands, hydraulic fluid for bleeding, and protective gloves. Do not attempt repairs without proper training; improper assembly can cause dangerous handling.

Maintenance Tips for Long Life

• Inspect air springs annually – Check for cracks, bulges, or leaks. Replace them proactively if they appear dry-rotted.
• Grease leveling valve linkage – A little lithium grease on the pivot points prevents sticking.
• Check ride height – The rear should sit level with the front. If one side is lower, investigate air spring or valve issues.
• Keep bushings lubricated – Polyurethane bushings need periodic regreasing to avoid squeaking.
• Regular alignment – After any suspension work, have the rear alignment checked, as worn bushings can alter camber and toe.

Final Recommendation

For most 1985 Bentley Turbo R owners, the best approach is to address the most common failure points first: replace leaking air springs with quality OEM-equivalent parts, install polyurethane bushings in the trailing arms for durability, and upgrade to modern gas shocks. If the self-leveling system gives repeated trouble, consider a coil spring conversion kit. Always purchase from established classic car parts suppliers or Bentley specialist dealers to ensure correct fitment. Avoid cheap no-name parts, as they can compromise safety and ride quality. With proper care, your Turbo R's rear suspension will deliver thousands of miles of comfortable and controlled driving.