Supports and hose clamp

Fuel tank brackets and retaining straps support the weight of the tank and absorb forces caused by braking, cornering, chassis flex and fuel sloshing. Correct mounting prevents movement, chafing and fatigue cracks in the tank wall. On MAN and Mercedes trucks, buses and vans, support brackets, retaining straps and rubber pads must therefore be assessed as a single mounting system. Simply tightening a loose strap will not remedy a bent bracket or a compressed rubber support pad.

Always identify parts using the vehicle's chassis number and check the tank version fitted. Visual comparison or selection based solely on the model name is never sufficient. Across MAN TGS, TGX and TGE or Mercedes Actros, Arocs and Sprinter models, for example, tank capacity, cross-section, mounting side and mounting points vary. On buses, the available installation space and body configuration also play a role. Engine variants and emissions equipment can affect the available chassis space, but do not on their own determine which tank brackets fit.

There are profiled support brackets for side mounting and retaining straps for underfloor tanks. Relevant selection parameters include strap width, material thickness, wrap-around length, bend radius, bolt hole spacing, thread size and the specified bolt property class. Steel components may be painted, galvanised or otherwise treated for corrosion resistance; replace them with a version offering suitable strength and protection. The support contour must match the tank geometry without creating point loads. On aluminium tanks, suitable insulating pads limit direct contact with steel mountings, thereby reducing fretting corrosion and galvanic corrosion.

Sizing is determined by the weight of the filled tank and the dynamic loads, not by fuel injection pressure. Strap preload, fit and support are critical: insufficient preload allows movement, while overtightening can deform the tank wall or a plastic tank.

Typical symptoms include knocking during braking, a tank sitting at an angle, contact surfaces rubbed down to bare metal and diesel-wet patches beneath retaining straps. Pay particular attention to strap ends, folded edges, weld transitions and areas where mud and road salt collect behind rubber strips.

1. Making safe: position the vehicle securely, avoid ignition sources and support the tank with suitable lifting equipment providing a broad support surface. If necessary, reduce the fuel level beforehand in accordance with the workshop procedure. Never release all mountings without independent support.
2. Cleaning and inspection: remove dirt and assess straps, brackets, bolts and chassis mountings for corrosion, cracks and elongated holes. Only remove pads once the tank is safely supported; check the concealed tank wall for wear caused by chafing.
3. Measurement: check bolt hole spacing and alignment using a rule and vernier calliper. After cleaning, measure accessible material thicknesses with a micrometer; localised corrosion may require ultrasonic thickness measurement. Compare the results with component drawings and manufacturer limits: there is no universal permissible loss of material thickness.
4. Determining the cause: check brackets for deformation using a straightedge and inspect rubber strips for hardening, cracks and permanent compression. Also investigate strain from fuel lines and contact with adjacent chassis components.

Replace cracked, heavily corroded or deformed mounting components; straightening or welding is not a standard repair. Use suitable pads and replace damaged fasteners. Fit straps flat, without twisting, and centre the tank on the support surfaces. Tighten connections in the specified sequence using a calibrated torque wrench, following the vehicle-specific tightening torque and the specified thread condition.

Then check clearances, ensure fuel lines are free from strain and check for any leaks at damaged contact areas. Carry out the final inspection with the tank filled to the specified level and recheck mountings only as directed by the maintenance instructions. Braem can provide technical support when selecting matching brackets, retaining straps and mounting components.