TL;DR

What:Removing E36 front seats, repairing the frame and recliner, rebuilding the foam and fitting new covers.
Why:Collapsed bolsters, torn covers and worn recliners are normal on a seat that’s 25-plus years old.
Safety:The front seat belt locks have tensioners: Bentley says to deactivate them before removing the seat and reactivate them afterwards.
Difficulty:3/5. Removal is easy; upholstery takes patience.
BMW E36 front interior with leather seats
E36 front seats in leather: the outer bolster of the driver's seat is usually the first to wear.Photo: Tim Alexander, CC BY-SA 4.0, via Wikimedia Commons

Common E36 seat problems

  • Collapsed outer bolster on the driver’s seat, from years of getting in and out
  • Worn or torn covers, especially on the bolster and the seat base edge
  • Sagging cushion from tired foam or broken support springs underneath
  • Loose or worn recliner mechanism, so the backrest moves or leans
  • Torn or missing plastic trim around the seat base and hinges

Removing a front seat (Bentley)

  1. Move the seat fully forward and as high as possible; remove the two bolts at the rear of the rails.
  2. Move the seat fully back, still raised.
  3. Disconnect the negative battery cable.
  4. Deactivate the front seat belt lock tensioners (Bentley 720 Seat Belts). Through the 1996 model year they’re mechanical spring tensioners; 1997-on cars have pyrotechnic (explosive) ones.
  5. Remove the plastic caps and the front mounting nuts.
  6. Two-door cars: unhook the belt from the guide on the seatback. Four-door cars: unbolt the belt from the seat frame.
  7. Tilt the seat back and unplug the electrical connectors.
  8. Lift the seat out. A blanket over the door sill prevents scratches.

Recliner and frame

  • Strip the seat to the frame and check the recliner mechanisms, the backrest hinges and the frame welds for cracks, wear and broken parts.
  • Worn recliner parts can be replaced with BMW parts (look them up by VIN on RealOEM, Seats) or with a good used seat frame. Aftermarket reinforcement kits are also sold.
  • Clean surface rust off the frame and paint it before the foam goes back on.
  • Check the support springs or straps under the cushion: broken ones make even new foam sag.

Rebuilding the foam

  • Local repair: cut out the collapsed area of the bolster, bond in shaped high-density upholstery foam with a suitable foam adhesive, then shape and smooth it. A thin layer of scrim foam over the top hides the joint.
  • New foam: where the whole cushion has collapsed, replace it. Check availability by part number on RealOEM for your exact seat (standard, sport, cloth or leather), as these differ.

Fitting new covers

  1. Warm the covers so they stretch more easily.
  2. Secure the centre first: the listing rods in the cover attach to wires in the foam or frame with new hog rings.
  3. Pull the edges down evenly and fix them to the frame. Work from side to side to keep the seams straight.
  4. Steam or gentle heat removes the last creases.

Refitting the seat (Bentley)

  • Secure the seat wiring with ties so it can’t fray.
  • Reactivate the front seat belt locks.
  • Start all four mounting fasteners, then tighten them in this order: inner front, outer front, inner rear, outer rear.
  • Front seat to floor: 55 Nm.

See also: door panel restoration · sound deadening