Bumper: Service and Repair
Bumper Repair\Renewal
Bumper Description
Each bumper comprises a beam mounted to the body via two strut assemblies and a moulded polypropylene cover incorporating side armatures and chrome plated plastic upper trims. The front bumper cover which is moulded to form a lower air intake for the cooling pack, also incorporates twin fog lamps, and side marker lamps or reflectors (dependent upon market). A plastic undertray secured to the lower edge of the front bumper and the body improves airflow and minimises the ingress of road grime in that area. Standard bumpers have glass mat thermoplastic (GMT) beams mounted on GMT struts. For certain markets, aluminium bumper beams are installed on menasco energy absorbing struts.
Bumper Cover Repair
Prior to commencing any work, bumper damage should be assessed for repairability and categorized in accordance with the following guidelines. Bumper covers that are torn or holed are not repairable and must be discarded.
CAUTION: Cosmetic appearance must not jeopardise safety. No attempt must be made to repair bumper covers damaged beyond category three. Damage of this extent will compromise the protective performance of the cover and it must be renewed. The thermo-setting nature of the cover material, precludes the repair of splits by heat or welding techniques.
Repair Materials
Repair of accepted damage for categories 2 and 3 may be carried out using 3M '5900 FPRM' (Flexible part repair material) or Kent Industries 'Urepatch'. Repair product manufacturers' recommendations and procedures must always be strictly followed.
Bumper Cover Refinishing
The paint refinishing system must be approved by Jaguar Cars Ltd., and be appropriate for polyurethane substrate application. It is essential that the finishing clear lacquer includes a plasticising ingredient (mixed to the manufacturer's recommendation) that will achieve the 'semi-flex' condition of the factory finished item.
Bumper Cover Support
CAUTION: During heat cure, the effective panel temperature must not exceed 95 degrees C.
Exposure to heat decreases bumper cover rigidity. Covers removed for repair must therefore be supported to prevent distortion and sagging during the paint curing process. Where the original bumper cover has been repaired, the beam will provide sufficient support for the centre section. It is recommended that the side armatures are supported as they would be on the vehicle. If a new cover is required, the beam may be temporarily fitted to provide the necessary support during refinishing.
Simple Jig Construction for Bumper Cover Support
Replacement Bumper Covers
Replacement covers are supplied in a primed condition and must be finished to match the vehicle.
Bumper to body Alignments and Clearances
New bumper covers and beams and replacement fixings such as bumper beam adjusters and guide blocks must be fitted and adjusted to achieve the following alignments and clearances:
Front Bumper to Hood Clearance
Front Bumper to Headlamp Clearance
Front Bumper to Fender Alignment
Front Bumper to Splitter Vane Clearance and Alignment
Rear Bumper to body Clearance
Rear Bumper to Wheel Arch Alignment
Recycling of Bumper Materials
The aluminium bumper beams fitted for some markets, should not be over-looked as components suitable for recycling.
Replacement bumper cover assemblies includer side armatures, which should be removed from discarded bumper assemblies and routed for recycling.
General Clearances and Alignments
When any panel, closure or body component is renewed, refitted or reset, the specified clearances and alignments must be restored. This ensures that vehicle appearance and operation fully satisfy design intent and the customer.
Clearances
Gaps should be uniform around body panel contours and must be parallel to within 1 mm in a 400 mm linear measurement. Panels centered between two adjacent panels must have equal gaps on either side. For exceptions to this, refer to the appropriate specification. Gaps between adjacent panels or components must not expose harnesses, labels, brackets or visually poor joint or assembly conditions.
NOTE: Sliding roof panel clearances are specified without the edge seal installed.
Areas of particular concern are, fuel filler flap, trunk lid to fenders and saddle panels, hood to fenders, grill and headlamps, sliding roof to main roof panel, door gaps at fenders, B\C posts, roof drip rail and rocker panel, and bumper cover to fenders and cross car assemblies.
Alignment
Panels must be correctly profiled to maintain cosmetic appearance, and ensure correct seating of seals with minimal wind noise. Areas of particular concern are hood to fenders, trunk lid to fenders and saddle panels, doors to apertures, doors to fenders and adjacent doors and relationship of the sliding roof panel leading and trailing edges to the main roof panel.
Exterior Fitments
Bezels, trims and lamps must be concentric with apertures and have equal clearances with adjacent panels.Areas of particular concern are headlamp to hood, fender and trim panel, exhaust tailpipe trim to bumper cover cut-out, rear lamp assembly to trunk lid, fender and bumper cover trim, and side feature lines including body side mouldings, fender to door and door to door.