Marathon Brake Systems developed a line of Heavy Duty Shock Absorbers for a range of truck, trailer, and severe service applications. These hydraulic shocks feature rugged construction with reinforced welds, tough end mounts, and durable piston seals to provide consistent performance over the life of the shock. The shocks have perimeter welding for the closing system, reinforced projection welded zones (8,000 lbs. maximum tensile strength of mounting), and endcap/outer tube welding that delivers 12,000 lbs. maximum tensile strength (assembly tested under 10-15 psi air pressure submerged in water without leaks). The shocks also utilize Super Chrome Piston Rods for extra durability and corrosion protection. These Piston Rods have temper hardness of 30-55 Rc, chrome plated surface hardness 67 Rc min., 0.0004" min. thickness, are dehydrogenized at 218°C for 70 minutes, a surface finish of Ra:6µ" and Rz:45µ”, and are salt spray test for 24 hours minimum.