Introduction: BMW Z3 Z3M Seat Rail Track Runner Sub Frame Mechanism Replacement Upgraded Bushes Bushings Fix Worn Rocking Repair Kit Instructions Install Guide

Symptoms of fault

Seats rocking or sliding forwards and back as you accelerate and brake. Wobbling or excessive movement. This is a very common fault with all Z3 models.

The problem

The seat rail bushings wear; causing excessive seat movement.

The poor quality rubber bushes within the seats sub frame tracks wear, perish or completely disintegrate and ultimately fail causing excess movement in the rails. This causes the symptoms noted above. This is a very common fault with all Z3 models. OEM replacement bushes if fitted would just fail again as these are also made from a poor quality rubber not suited to the application.

Vehicles affected

All Z3 models

Z3 E36 E37 E38 1994-2002 Roadster and Coupe.

Z3M M Roadster M Coupe

Associated part numbers

52108401291, 52108401292, 52108399593, 52108398812, 52107137499.

The solution

Fit our upgrade seat runner bushes and stop the excess movement in your seats.

Our repair bushes are easy to fit and will cure these faults permanently. Constructed from the proven material Delrin; our part will not deteriorate like the OEM bushes and are designed to last the lifetime of the vehicle. Our kit includes 8x bushes to repair both passenger and drivers seats. An extremely common fault fixed with our repair kit.

What you’ll receive:

8 bushes to repair 2x seats; drivers and passengers.

Available exclusively from X8R Ltd

Step 1: Remove the Seat Belt

  • Start by undoing the 16 mm bolt holding the seat belt to the base of the seat
  • Once undone, you'll need to slide the seat belt through its locator/holder as shown in the picture
  • Now that the seat belt is removed, tuck it out of the way

Step 2: Unbolt the Seat

  • Slide the seat to the furthest forward position, to allow access to the two 16mm bolts at the rear of the seat rail
  • You may need a small extension on the socket to allow you to undo the bolt using a ratchet
  • Slide the seat completely back to allow access to the two 13mm nuts on the front of the seat rail.

Step 3: Unplug the Electrical Connectors on the Under Side of the Seat

  • With the seat unbolted you're be able to access the electrical plugs for the seat motors etc
  • Slide the yellow plug from its slot and unplug, for the white plug - press down on the two tabs and remove the plug
  • This being the drivers side seat, there are two additional plugs you need to undo. Depending on the spec of your vehicle there may possibly be more. Before removing from the vehicle please check that the wiring is all unplugged and out of the way.

Key points for this stage:

You may find it slightly easier to remove the seat from the vehicle if the roof is folded down but this not necessary.

Once the plugs are disconnected please DO NOT start the vehicle or switch the ignition on - this will cause the vehicle to think there's a fault, which will switch on a warning light on the dash unnecessarily.

Step 4: Remove the Old Bushes From the Seat Runner

  • Remove the two T25 torx screws located on the seat runner
  • With the two torxs removed, the runner will be free to slide further up and down
  • Remove the T50 torxs from the seat runner
  • Grip the top on the spindle were the T50 torx is located and wiggle the spindle, when its starts to move - lift it out
  • Also lift the seat runner until the seat spindle is free from the runner

Step 5: Remove the Old Bushes

  • Unwind the seat bush housing from the spindle, counting how many turns it takes to remove - this is important when it comes to refitting the spindle
  • With the spindle removed lift out the center part of the housing
  • Clean out what remains of the old bushes

Step 6: Fit the New Bushes

  • With the housing cleaned fit the new bushes
  • Slot both of the new bushes in, then the center part

It can be a bit tricky to fit first time, so using some 80 grit sand paper rub back the bushes equally on the both sides until the center part slots in but still creates a tight fit

  • When you have the center part slotted in, press in fully as shown in pictures making sure it locates centrally.

Step 7: Fit Back Into the Runner

  • Slot the spindle back into the bush housing and wind it up, counting the turns
  • Slide the spindle in to the runner, making sure the drive gear slots in correctly
  • Apply some thread lock and fit the T50 torx

  • Line up the bolt holes for the T25 torx and re-fit

Repeat these steps for the other runner and refit the seat to the vehicle following the removal instructions in reverse.

If you need any further guidance on this install or would like to purchase the parts shown please call us on +44 01843 446643 or email us at

Please also check out our instruction guide on YouTube.

Installation is carried out at installers risk, if unsure please contact us or a professional, X8R Ltd cannot be held responsible for any adverse result of installing this product or any injuries caused by install, if in doubt ask a professional. All images and texts are copyright X8R Ltd 2013