Eccentric Bolt Rear Suspension. Porsche 928 1986-95

Eccentric Bolt Rear Suspension.
Restore or maintain the alignment-adjust capability of your Porsche 928’s rear suspension with this eccentric bolt. Designed for the 1986–95 928 series (including S2, S4/GT, GTS), this offers direct replacement for the original rear trailing arm / cross-member adjuster. By repositioning the bolt within its eccentric housing, precise adjustment of camber or toe is achievable — helping lock the rear geometry securely and ensuring accurate, stable handling. Sold individually (two recommended per vehicle), this adjuster bolt is a key maintenance item when refreshing the rear suspension or correcting alignment issues.
Sold Each.
x2 Required Per Car.

Fits:

• Porsche 928S2 4.7L 1984-86
• Porsche 928S4 5.0L 1987-92
• Porsche 928GT 5.0L 1989-91
• Porsche 928GTS 5.4L 1992-95

Diagram Ref No 17

What This Product Does:

• The eccentric bolt is part of the rear suspension trailing arm / cross-member assembly. It allows for precise adjustment of the rear suspension geometry — typically for camber, toe or longitudinal arm position via the eccentric nature of the bolt.
• Being “eccentric” means the bolt shaft is offset inside its housing so that when the bolt is rotated or repositioned, the trailing arm or mount moves slightly (i.e., the arm moves in or out by a small amount) to allow alignment adjustment.
• It helps set and maintain correct alignment (especially toe and camber) of the rear suspension arms relative to the body and chassis — critical for handling, stability and tyre wear on the 928’s rear suspension.
• When adjusted correctly and properly torqued, the bolt holds the arm or cross-member in its correct location and prevents unwanted movement or geometry shift under load.

Symptoms Of Wear, Mis-Adjustment Or When It Needs Attention:

• The rear alignment is out of specification or cannot be held — especially rear toe or camber that keeps shifting or adjusting.
  
• Unusual tyre wear on the rear tyres — inner or outer edge wear due to geometry changes under load.
  
• Rear instability or vague handling — the car may feel less precise, especially in corners or under acceleration/braking, because the arm location isn’t locked down.
  
• Loose or knocking noises at the rear suspension — if the eccentric bolt or its housing is worn, movement might occur.
  
• During inspection, you find the eccentric bolt is corroded, seized, has stripped threads, or the slot for adjustment is damaged — making accurate adjustment impossible.
• After a suspension service or arm replacement, the bolt or its seat looks malformed or the previous adjustment marks don’t align — indicates repeat adjustments or wear.

Why Replacement Matters:

• Ensuring the eccentric bolt is in good condition and correctly torqued is fundamental to rear suspension geometry, which directly influences handling, stability, and tyre life especially in a high-performance car like the 928.
• A worn or sloppy adjuster can allow the arm to shift under load — reducing precision, creating instability, and wearing tyres faster.
• In restoration or performance setups (larger tyres, stiffer springs, lowered ride height) the demands on geometry tighten — having a firm, adjustable mount is critical.
• Replacing the bolt or upgrade stiff fixation means alignment stays correct for longer, adjustments are reliable, and the suspension performs as designed.
• From a safety viewpoint, correct alignment and arm location help ensure the vehicle behaves predictably in high-load or hard-cornering scenarios.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

92833165905

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