Home/Citroen/C4/Citroen C4 II (2010-2016)/Repair manual/Side structure/Replacement: outer sill (understructure)
Contents Wiring diagrams Section: Side structure All sections

Replacement: outer sill (understructure) Citroen C4 II

Side structure ~547 words

WarningObserve the safety and cleanliness recommendations

WarningObserve the precautions to be taken for the pre-tensioning components

WarningAll of the stripped surfaces must be protected by means of the approved electrolytic rezincing process

WarningThe number of spot welds necessary for the assembly of a new part must be identical to the number of spot welds fixing the original part

Information

Types of weld bead by electric arc procedure on this component

MAG welding with steel rod and used with active gas

Designations of the high strength steels used in this document

  • ADX: soft steel
  • HLE: high-strength steel
  • THLE: very high-strength steel
  • UHLE: ultra high strength steel

NoteUse the products recommended by the manufacturer

Tooling

toolReferencedesignation
[1366-ZZ]toolkit for testing electric spot welds
[1366]samples for testing electric spot welds
[1126]set of spot weld cutters
swan's neck drill for cutting out electric spot welds
hot air blower

Preliminary operations

Deactivating the pyrotechnic systems

Disconnect the battery

WarningRemove or protect the components that are in the repair area and that can be damaged by heat or dust

Remove

  • Front wing
  • Front mud flaps
  • Front door
  • Rear door
  • INTERIOR TRIMS (side sill)
  • Central pillar trim
  • Rear bench seat
  • Front seat

WarningIf the vehicle is fitted with the Stop and Start system, discharge the power accumulator

Release the wiring harnesses

Replace the expanding inserts

Location of the replacement part

referencedesignation
(1)outer sill (understructure)

Identification of the replacement part

Composition: outer sill

referencedesignationthicknessnature/classification
(1)outer sill0,67 mmADX

Identification of the parts adjacent to the replacement part

referencedesignationthicknessnature/classification
(2)front wing inner panel1,17 mmhigh strength
(3)front pillar inner panel1,17 mmhigh strength
(4)centre pillar upper strengthener1,76 mmUHLE
(5)centre pillar inner panel0,97 mmHLE
(6)rear wing inner panel (front section)0,67 mmADX
(7)inner sill1,47 mmhigh strength
(8)centre pillar lower reinforcement1,27 mmhigh strength
(9)inner sill strengthener0,77 mmTHLE

Replacement part preparation

WarningWhen cleaning the mating edges, use scouring wheels only to avoid damaging the anticorrosion protection

Mark, then cut (at "a", "b", "c")

NoteThe cuts "a", "b", "c" are given as a guide and can change according to the different cases for replacement

Mark then pierce to a diameter of 6,5 mm for later plug welding

Prepare the mating edges and protect them using a weldable primer (index "C7")

NoteApply the weld-through primer on the internal faces of the panels to be welded

Cutting of the part on the body

Mark (at "d", "e", "f"), then cut out

NoteThe cuts "d", "e", "f" are given as a guide and can change according to the different cases for replacement

Cut out the spot welds

Detach the outer sill panel at the inflating insert (10); using a hot air gun

Remove the exterior longeron

Cleaning and preparation of the body

Prepare the mating edges and protect them using a weldable primer (index "C7")

NoteApply the weld-through primer on the internal faces of the panels to be welded

Prepare the mating edges

Apply a filling adhesive (index "A1")

Identification of the expanding inserts - sealing foam

Adjustment

Position

  • The outer sill
  • The components for adjusting

Check the fits and clearances

Adjust the cuts (if necessary)

Holds the part in position

Welding

Weld by MAG bead (at "g")

Grind the MAG weld beads

Weld with MAG plug welds

Grind the MAG plug welds

Weld with electric spot welds

Weld with electric spot welds

Sealing protection

Apply a phosphate-print layer to the zones laid bare

Apply a sealing mastic of type "A1"

Apply a phosphate-print layer to the zones laid bare

Apply a sealing mastic (index "A1")

Anti-chip protection

Painting, then spraying of the index "C5" product into the hollow sections in the repair zone

Additional operations

Refit the electrical harnesses and the components removed

Reinitialisation

Put the pyrotechnic systems into service

WarningPerform the operations to be carried out following reconnection of the battery

Reconnect the battery