System Component
Body StructureThe body dimensions have been increased to improve roominess in the rear compartment (+ 5 cm knee room) and to increase the luggage compartment capacity (at 520 L the largest capacity of all the BMW vehicles including the E65).
In order to make the E60 significantly lighter than the current 5 Series, BMW designed a "reduced-weight aluminum front end" (GRAV).
The front end consists almost entirely of aluminum while the transition to steel occurs in the front bulkhead area. Aluminum components are shown in darker shaded (front clip) section.
The weight saving at the front end not only reduces the total weight of the vehicle but is also a significant factor in the E60 attaining the ideal axle load distribution of 50/50.
On the one hand, an aluminum body section offers reduced shielding against external electrical radiation, making it necessary for separate shielding of the wiring harnesses and electronic control units.
On the other hand, riveted and bonded aluminum components do not always provide a guaranteed circuit to ground. This results in individual front end components being connected (in production) with small EMC safety weld seams and in the event of repair, with grounding straps.
1. Spring Support
2. Engine Support
3. Bulkhead carrier support
4. Outer connection (steel)
5. Bulkhead Cross Member
6. Bulkhead
7. Inner A pillar (steel)
The transition from the aluminum front engine support rail to the steel rail section joint (connection) is produced by bonding and punch riveting.
To increase conductivity, ground points are located on the two rails and are connected with a ground strap.
In addition to the underhood strut tower V- struts (2 lower left), the bumper carrier (1 lower right) and thrust panel (2 lower right) provide additional reinforcement and structural rigidity.
Note: The V-struts, bumper carrier and thrust panel must be installed and property torqued before the vehicle is driven. If not, the rigidity of the front end will be considerably reduced leading to noise and structural damage
The crash box is a deformation element specially developed for the E60.
The crash box is part of the side frame and is secured at the bottom of the A-pillar.
In the event of a frontal crash, the crash box absorbs forces that are transmitted via the front wheel into the side frame in the sill area. The E60 also integrates the familiar side impact protection gards (steel).
These are bolt on parts that must be replaced when damaged.
K 1 -02600
Body Repair
Repairing an aluminum body requires completely new repair methods in body shops with properly trained personnel, as well as proper tools and equipment.
Aluminum materials can not be "stretched", this rules out the possibility of pulling on a straightening bench. Components deformed as a result of an accident must always be replaced, which incurs more extensive training, tools and assembly procedures than is the case with steel bodies.
Using the frame rail as an example, deformed E60 aluminum components must be cut off at permanently defined points and replaced by new components.
Special insert repair elements made of aluminum are required to ensure that the replacement parts are safely and securely held in place.
The insert element for repairing aluminum (top left) is inserted into profile chambers and then expanded into place by bolts (refer to the E60 SIP for more details).