As part of a thorough check & repair of the few nuisance items found in a recently acquired 1982 W126 300SD, I used a different method of repairing broken seat springs in the driver's seat.

Instead of using tie-wire or safety wire as described elsewhere, I used cable clamps like those intended for use with flexible steel cable. The threaded U-bolt that pulls a grooved casting towards the bottom of the U works very well to hold the inserted broken ends of the spring wire.

If the break to be repaired is near a 90 degree turn in the spring wire, it is possible to realign the ends by a fair amount to make them closer to parallel, to better align them to fit into and through the clamp. Use the closed end of a box-end wrench (13mm) held tightly in a locking-type pliers to slip over the broken end and twist the wire to realign; the spring wire can bent even though it has some carbon in it to produce stiffness.

Tighten the nuts well on the U-bolt, using lockwashers or liquid thread-locking compound.

Remove the seat from the floor of the car as described in other threads here, but do not remove the Phillips head screws found inside the ends of the seat rails, in an attempt to remove just the seat box itself. Take the entire seat out after removing only the five 10mm bolts and place it upside down on a padded surface.

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Respect, protect, and maintain complex systems - whether natural or of German design, to benefit from their full potential.

1982 300SD W126.120 with an OM617.950 from a W116.120
1984 300SD W126.120 with an OM617.951