Door and door extension

Doors and door extensions protect the cab from the elements, reduce driving noise and form an essential part of passive safety. In this category, you will find complete doors, door frames, door extension sections, outer panels, inner shells and structural mounting parts for MAN and Mercedes trucks, buses and vans. Applications range from MAN F90, F2000, TGL, TGM, TGA, TGS, TGX and TG3 to Mercedes LN, SK, Atego, Axor, Actros, Antos, Arocs and Econic, as well as vans such as TGE, Sprinter, Vito and Vario. Door constructions also vary considerably by version on MAN Lion’s City, Lion’s Coach, Neoplan coaches and Mercedes Citaro or Tourismo buses.

A part must always be identified using the vehicle chassis number. Visual comparison or selection based solely on the model name is never sufficient. Door height, hinge spacing, window opening, cut-out for entrance steps, mirror mounts, central locking, electric window operation and cab variant together determine the correct version. On truck cabs, door extensions for high-roof cabs, sleeper cabs or specific chassis body configurations may also differ from one another.

Cab doors generally consist of a steel outer skin, reinforcement profiles, an inner shell and anti-corrosion coatings. Depending on the vehicle series, aluminium parts, plastic covers and composite extension sections may also be used. Door extensions connect to the door, entrance step or rear wall of the cab and must retain the original contour, sealing and airflow guidance. Incorrect fitment causes wind noise, water ingress, accelerated wear of door seals and stress on hinges or striker plates.

Common types of damage include dented outer panels caused by collisions, torn hinge mounting points, corrosion along the lower edge, deformed window guides and cracked door extension sections after contact with loading docks or obstacles. On vehicles frequently used on construction sites, such as the MAN TGS or Mercedes Arocs, dust, stone chips and mud often cause wear to seals and locking mechanisms. On distribution vans, including the Sprinter and TGE, sagging driver’s doors and worn door check straps are a frequent result of intensive entry and exit.

Start the diagnosis by checking the body panel gaps around the closed door. Measure the gap at several points using a feeler gauge; uneven gaps indicate a sagging door, a deformed frame or damage to the A-pillar. Then check the radial and axial play of the hinge pins by gently lifting the rear edge of the door. Visible movement at the hinge indicates wear of the pins, bushes or mounting plates.

First check whether the latch engages the striker plate without force. A door that needs to be pushed upward to close must not be corrected solely by adjusting the striker plate: first restore the hinge alignment or structural mounting. Then test the seal using a strip of paper around the entire perimeter; a strip that can be pulled out without resistance indicates insufficient contact pressure or a compressed door seal. In the event of water leaks, carry out a targeted water test from top to bottom and check the drain openings at the bottom of the door for blockages.

Replace a complete door when the outer skin, window frame or hinge area is permanently deformed. Straightening work on load-bearing hinge components can adversely affect fitment and side-impact safety. A separate door extension section can generally be replaced when the surrounding cab panel, mounting points and sealing surfaces are undamaged. Before fitting, always check the presence and position of clips, weld nuts, water barrier films, cable grommets and mounting brackets.

First fit the door loosely onto the hinges, adjust the panel gaps and only then centre the striker plate, window guides and seals. Damaged corrosion protection on steel must be restored using suitable primer, seam sealer and paint system. Parts with correct fitment and, where applicable, supplied in colour reduce installation time and prevent additional work in the paint shop.