suspension
Replacing Porsche 930 Trailing Arm Bushings: A Technical Guide
Overview
Replacing trailing arm bushings on a Porsche 930 is a critical maintenance task for preserving the iconic chassis's handling dynamics. Over time, original rubber bushings degrade, causing toe and camber fluctuations that result in unpredictable handling and excessive tire wear.
Technical Details
The 930 trailing arm system relies on precise geometry. When replacing bushings, ensure the arm is properly indexed to maintain factory alignment specs. Most experts recommend switching to high-durometer rubber or precision-fit Delrin/bronze bushings to eliminate deflection without sacrificing too much ride quality. Tightening the pivot bolts must be done while the suspension is at its loaded ride height (at the nominal driving position) to prevent premature bushing failure due to pre-load stress.
Tools & Parts
- Press tool set for trailing arm bushings
- High-quality rubber or performance bushing set (polyurethane/Delrin)
- Torsion bar removal tool
- Torque wrench
- Moly-lithium grease (if using aftermarket bushings)
- Penetrating oil for seized bolts
Common Issues
- Seized eccentric adjustment bolts due to corrosion
- Torsion bar binding during removal
- Difficulty in pressing out the old, hardened rubber shells
- Improper alignment after reinstallation leading to bump steer
Steps
- Lift the vehicle securely and remove the rear wheels.
- Disconnect the parking brake cables, brake lines, and shock absorbers.
- Remove the torsion bar covers and extract the torsion bars.
- Unbolt the trailing arm from the spring plate and the chassis pivot point.
- Use a hydraulic press to extract the old rubber bushings; clean the housing thoroughly.
- Press in the new bushings, ensuring they are perfectly aligned with the pivot axis.
- Reinstall the trailing arm, torsion bars, and spring plates.
- Torque all suspension fasteners to factory specifications with the suspension under load.
- Perform a full professional 4-wheel alignment.
FAQ
Frequently Asked Questions.
Should I choose rubber or polyurethane bushings for my 930?+
Rubber bushings provide the best NVH (noise, vibration, harshness) damping for street use. Polyurethane or solid bronze bushings offer better performance and tighter handling but can transmit more road noise into the cabin.
Do I need to realign the car after replacing trailing arm bushings?+
Yes, it is mandatory. Replacing these bushings disturbs the rear suspension geometry, and a precision 4-wheel alignment is essential for safe handling.
Why is it important to tighten bolts at ride height?+
Tightening the fasteners while the suspension is hanging (unloaded) creates excessive wind-up stress on the bushings, leading to immediate premature failure once the car is lowered back onto its tires.
Need This Done Right?
Bring your Porsche to Blamm Motorwerks in Laguna Beach — independent Porsche specialists with factory-grade tooling and real expertise.