Caterpillar WE-851B

The Caterpillar WE-851B is a self-propelled asphalt windrow elevator, not a paver itself: it runs ahead of a separate Cat asphalt paver, picks up windrowed hot mix off the grade, and lifts it by conveyor into that paver's hopper. It carries no screed, no mat-width control, and no bucket or work-tool couplers. Power comes from a Perkins 6.354.4 inline six-cylinder diesel, a mechanical engine with CAV fuel injection and no ECM or electronic diagnostics. Caterpillar catalogued the WE-851B under the 8BC serial prefix and built it roughly from the mid-1980s into the early 1990s, alongside its smaller sibling the WE-601B (7EC prefix); the two were marketed together in Caterpillar's 1987 windrow-elevator brochure. No operating weight or dimensional spec sheet survives in public Caterpillar literature for the WE-851B, and only a single configuration is documented: a wheeled, hydrostatically driven chassis towed and hydraulically linked behind the paver it feeds.

Documentation on running changes within the WE-851B's production life is thin; surviving Caterpillar literature covers it as one generation rather than a tracked series of engine or chassis updates. What is well documented is the exit: Caterpillar sold its windrow-elevator product line to Weiler in 2005, and Weiler carried the concept forward as the E-series (E550/E650/E2850 and later updates), ending Caterpillar's direct participation in this niche. That makes the WE-851B a closed-book category in the used market: no factory replacement, no current Cat parts program built around it, and support that runs through generic Perkins mechanical-diesel channels for the engine and Caterpillar's paving-parts network for the elevator's own conveyor and hydraulic components. Buyers still run these units because a fully mechanical Perkins diesel with no ECM is simple to keep alive in the field, and a working windrow elevator remains an inexpensive way to feed an older Cat paver without buying a modern, computer-controlled replacement.

Below: full specifications, fluids & capacities, the factory service schedule, common service parts, verified fault codes, what owners discuss, attachment guidance, the complete assembly directory, and a serial-number reference. Complete parts lists with full OEM part numbers, exploded diagrams, quantities, and fitment data are available free in Heavy Parts AI.