Bilstein 19-323312 B4 Rear Shock Absorber - BMW 3 Series G20 G21 & M3 G80 G81 OE Replacement (Rear Axle, Gas-Pressure Twin-Tube)

Bilstein B4 19-323312 Rear Damper for BMW 3 Series G20 G21 and M3 G80 G81

Restore that fresh-from-factory feel on your BMW with Bilstein’s B4 rear suspension unit. Part number 19-323312 is a direct-fit, stock-spec replacement for the back axle on BMW G20 and G21 3 Series plus G80 and G81 M3. Expect confident road holding, stable cornering and smooth ride comfort thanks to Bilstein’s proven gas-charged twin-tube architecture and OE-grade valving.

If you are hunting for a BMW rear strut, rear shock for G20 saloon, G21 Touring estate damper, or an M3 G80/G81 rear suspension replacement, this genuine Bilstein B4 delivers the OEM quality you want with the plug-and-play fit you need. Perfect for cars that have become bouncy, crashy or unsettled over bumps, or if you are eliminating knocks from tired original shocks.

Why this B4 rear damper is the smart choice

• Factory-spec feel with crisp control and day-one comfort
• Gas-charged twin-tube design for consistent damping on rough UK roads
• Simple bolt-on installation to the rear of the vehicle
• Improves traction, braking stability and mid-corner composure
• Built by Bilstein for long service life and dependable performance
• Ideal for daily driving, motorway commutes and quick B-road runs

We have installed these on customer cars and on our own builds at MJ Modifications. Feedback is repeatedly positive: better body control, a planted rear end and noticeably improved comfort without harshness. It is the go-to solution when renewing BMW 3 Series or M3 rear suspension components with an original-quality part you can trust.

Key advantages

• OEM-grade ride quality and handling balance
• Stable damping across varying loads and temperatures
• Precise road feel without sacrificing comfort
• Genuine Bilstein component engineered for BMW applications

Technical details

• Location: Rear, back axle
• Type: Gas-charged, twin-tube
• Spring seat: Shock does not carry a coil spring
• Mounts: Bottom eye, top pin

Vehicle compatibility

BMW 3 Series and M3 platforms:

• 3 Series Saloon 3 G20 G80 11.18 onwards
  • 320e Plug-in-Hybrid, 330e Plug-in-Hybrid, 330e Plug-in-Hybrid xDrive
  • 316d Mild-Hybrid, 318d Mild-Hybrid, 320d Mild-Hybrid, 320d Mild-Hybrid xDrive
  • 330d Mild-Hybrid, 330d Mild-Hybrid xDrive, M340d Mild-Hybrid xDrive
• 3 Series Touring 3 G21 G81 07.19 onwards
  • 320e Plug-in-Hybrid, 330e Plug-in-Hybrid, 330e Plug-in-Hybrid xDrive
  • 318i, 320i, 330i, 330i xDrive, M340i Mild-Hybrid xDrive
  • 316d, 316d Mild-Hybrid, 318d, 318d Mild-Hybrid
  • 320d, 320d Mild-Hybrid, 320d xDrive, 320d Mild-Hybrid xDrive
  • 330d, 330d Mild-Hybrid, 330d xDrive, 330d Mild-Hybrid xDrive, M340d Mild-Hybrid xDrive
• 3 Series Touring Van G21 07.19 onwards
  • 320i, 330i, M340i xDrive, 320d, 320d Mild-Hybrid, 320d xDrive, 320d Mild-Hybrid xDrive, 330d, 330d xDrive

Fitment help

Unsure if this is the correct rear unit for your chassis. Send us your UK registration or the last 7 digits of your VIN and we will confirm compatibility before dispatch.

Professional installation

Prefer us to fit it. MJ Modifications offers expert suspension installation in Warwickshire. Request a quote at info@mjmodifications.co.uk.

Part numbers and identifiers

• Bilstein Part Number: 19-323312
• SKU Reference: BILSTEIN-19-323312
• EAN: 4025258879525
• UPC: 651860887227

Buy with confidence from MJ Modifications

Genuine Bilstein B4 rear damper for BMW G20, G21, G80 and G81. Perfect for anyone searching for BMW rear strut replacement, BMW 3 Series back shock, G20 rear suspension damper, G21 Touring rear shock or M3 G80/G81 rear shock. Fast, reliable and built to deliver that tight, composed BMW feel you love. Add to basket and refresh your ride today.