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Air Over Hydraulic Master Cylinder for Caterpillar 518, 528, 920, 930 | 9K1591

SKU:
9K1591
FitsModel:
518, 528, 920, 930
ListDescription:
Air Over Hydraulic Master Cylinder
Air Over Hydraulic Master Cylinder for Caterpillar 518, 528, 920, 930 | 9K1591
Part # 9K1591

Fits Models At A Glance:

  • Caterpillar Wheel Skidders: 518, 528
  • Caterpillar Wheel Loaders: 920, 930

Serial Number Notes:

  • 518: 94U00001-UP, 95U00154-03199, 50S01289-03229
  • 528: 96C00001-UP, 51S00288-00736, 78W00001-00365
  • 920: 41J00001-UP, 62K00001-UP
  • 930: 41K00001-UP, 71H00001-UP, 73U00001-UP, 79J00001-UP, 8CB00001-UP

Key Notes:

  • Part Number: 9K1591 (Caterpillar reference 9K-1591)
  • Position: Air Over Hydraulic Brake Master Cylinder
  • Bore: 1-1/4 in inner diameter
  • Stroke: 1-7/16 in
  • Dimensions: 6-7/16 in overall length
  • Material: Carbon steel
  • Weight: 2.3 lbs.
  • Condition: Aftermarket replacement part
  • Application: Replaces the air over hydraulic brake master cylinder on Caterpillar 518 and 528 wheel skidders and 920 and 930 wheel loaders
  • Shipping Restrictions: Ships to the lower 48 US states only
  • Note: Cylinder only - diaphragm, gaskets, air lines, fluid and mounting hardware are not included. Caterpillar publishes an approximate weight of 4.71 lbs for this cylinder while the supplier catalog lists 2.3 lbs; the shipped weight may differ from the figure shown here.

Common Use Case or Symptoms:

Replace this when the brakes drag, release slowly, or the pedal builds air pressure without building brake pressure - on an air over hydraulic system the master cylinder is the hand-off point between the two circuits, and when it fails the operator gets air at the pedal and nothing at the wheels.

Why Choose Broken Tractor?

  • ✅ Air To Hydraulic Hand-Off: This is the cylinder that turns compressed air into hydraulic brake pressure, so it is the single point where an air-over system either works or does not.
  • ✅ Bore And Stroke Published: 1-1/4 in bore and 1-7/16 in stroke, which is what separates this cylinder from the others in the same family on the bench.
  • ✅ Skidders And Loaders Together: The 518 and 528 skidders share this cylinder with the 920 and 930 loaders, so a mixed fleet stocks one number.
$93.00

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Product: Category: Brand: Head Title: Air Over Hydraulic Master Cylinder | Broken Tractor | 9K1591