Used Combine Harvester Screens and Pre-Screens

The Role of Screens and Pre-Screens in Cleaning

After the threshing components and the counter-beater, the mixture of grain, small straw, and chaff falls from the shakers onto the pre-screen, which distributes it to the cleaning chamber. Within the combine harvester’s cleaning system, the adjustable slatted upper screen lets grain pass through while retaining chaff, which is sent back to the beater for a second pass. The lower screen, being denser, performs the final sorting: only clean grain reaches the grain auger and then the hopper. The airflow from the fan passes through both screens, removing short straw and light impurities. A deformed screen prevents effective separation, regardless of the adjustment.

Used Screens and Pre-Screens Available at TMC Bejenne

• Adjustable slatted upper screens, also known as chaff screens.
• Lower calibration screens, adjustable or fixed-hole types.
• Pre-screens and preparation tables feeding the cleaning chamber.
• Screen extensions mounted at the rear of the upper screen.
• Fine screens and long-slot screens for rapeseed and small seeds, or maize screens, depending on availability.
• Parts sourced from combines by New Holland, Claas, John Deere, Case IH, Massey Ferguson, and Laverda.

Adjustable Combine Harvester Screens: Adjustment and Repair

Adjustable screens should be checked in the field at a steady forward speed. Impurities in the hopper indicate an opening that’s too wide; grain losses behind the machine mean the screen is too tight or the airflow is too strong. The lower screen is always set tighter than the upper screen. Spacing values for different crops such as soft wheat, barley, or rapeseed are provided in the manufacturer’s manual: start with those guidelines and fine-tune according to grain maturity and straw condition. For repairs, a slightly warped frame can be straightened and cracked welds fixed. However, when the slats no longer hold their setting or the frame is deformed, replacing the screen with a used original part often costs less than repairing. New aftermarket screens may also require fitting adjustments.

Signs That a Screen or Pre-Screen Needs Replacing

• Slats worn by abrasion that move independently during operation.
• Frames or welds cracked from cleaning chamber vibrations.
• Deformed or enlarged holes on fixed-hole screens.
• Bent entry comb creating dead zones on the screen.
• Dirty grain or persistent grain losses despite correct settings.
• End of service life: screen lifespan depends on threshing surface and abrasion from dry crops.

Combine Harvester Screens and Pre-Screens by Brand

Note the brand, exact model, and year of your combine, along with the part position: upper screen, lower screen, pre-screen, or extension. The cleaning chamber width and the reference number stamped on the frame differentiate two seemingly similar screens, even within the same combine model series. Our technical team compares these elements to ensure effective separation once installed. Our combine screens come from models such as Claas Dominator 58, Lexion 570, or Medion 310; New Holland CX 740; John Deere 1550 or T660; and Massey Ferguson 7270. Models evolve with each dismantling. Specialist in used agricultural parts since 1945, TMC Bejenne dismantles machines on its 11-hectare site in Naintré and relies on a stock of 25,000 references. Quotes and advice at 05 86 24 00 26.