E30 seats are notorious for breaking the brackets that mount the seat back to the seat bottom. The stamped metal used there has two failure points – one at the welded nut and one at the 90 degree bend.

Fixing is possible by way of welding, but the bracket often re-fails slightly up or down stream of the welds. The bracket below had already been welded once and has broken again at both failure points:

Removing the broken bracket:

The bracket is attached to the hinge with a single steel rivet. Grind or drill off the rivet head, push the rivet out, and the bracket comes right off:

The permanent fix:

Once removed, you can use our repair kit to permanently solve this issue. The new bracket is CNC machined from solid billet — the thread is machined directly into the material, so there is no welded nut to crack off and no thin bend to fatigue. It is completely weldless and bolts on through the two existing holes with the included hardware:

Available here:

https://www.rtsauto.com/e30-seat-back-mounting-repair-brackets-tabs-sport-comfort-4-door-2-door/

Seat hinge interchangeability (2 door, 4 door, convertible, Sport, Comfort):

All E30 seats except the early 84-85 seats have interchangeable seat hinges — 2 door, 4 door, convertible, Sport and Comfort all use the same hinge mechanism. The differences are minor:

The only difference between Sport and Comfort seats is that Comfort seats use just one shock, on the outer side hinge, instead of one on both hinges. The shock only assists when pulling the lever to tilt the seat back forward or back.

The only difference with convertible hinges is a slightly different shaped plastic adjustment handle.

All hinges can tilt, whether they came from a 2 door or a 4 door. On a 4 door the tilt function is simply not used (the cables are removed from the seat back), but the hinge mechanism itself is the same — so 2 door and 4 door hinges swap freely.

For other common seat failure points to look out for, see:

Failure Points of E30 Sport Seats

This entry was posted on July 16, 2026 at 4:19 pm and is filed under Do it Yourself. You can follow any responses to this entry through the RSS 2.0 feed.