Caterpillar publishes no replacement or superseding number for 9K-8943.
9K1591 (Caterpillar 9K-1591) is the master cylinder that works inside this group and is stocked separately - order the group when the air chamber or housing is at fault, and the cylinder alone when it is not.
Caterpillar lists these service items against the same group: gaskets 5H-3703, 4H-6145 and 1K-6519, bolt 4H-6143, and brake control valve inlet connection 5K-3713.
Caterpillar additionally catalogues 9K-8943 against the 528B and 530B skidders, which the supplier list does not carry.
Key Notes:
Part Number: 9K8943 (Caterpillar reference 9K-8943)
Position: Air Over Hydraulic Brake Cylinder Group
Dimensions: 172 mm outer diameter
Function: Converts air system pressure into hydraulic pressure to actuate the brakes
Material: Steel housing with air chamber
Weight: 17.1 lbs.
Condition: Aftermarket replacement part
Application: Replaces the air over hydraulic brake cylinder group on Caterpillar 528 wheel skidders and 920 and 930 wheel loaders
Shipping Restrictions: Ships to the lower 48 US states only
Note: Supplied as the cylinder group. Gaskets, air lines, brake fluid, control valve and mounting hardware are not included, and the diaphragm is a separate service item. Confirm the air chamber diameter against the unit being removed.
Common Use Case or Symptoms:
Fit this when the air chamber has ruptured, the housing is leaking at the crimp, or the brakes will not release after the pedal comes up - on a skidder in the woods a hung brake means a dragging wheel and a burnt drum before the operator is back at the landing.
Why Choose Broken Tractor?
✅ Complete Cylinder Group: The air chamber and hydraulic section together, so a ruptured diaphragm housing does not have to be rebuilt in the field.
✅ Seventeen Pound Assembly: Substantially heavier than the master cylinder alone, which is the quickest way to tell the two numbers apart when ordering.
✅ One Group Three Machines: The 528 skidder and the 920 and 930 loaders all take the same group.
$204.00/ea
Shipping calculated at checkout. If any item in your order is temporarily unavailable, we'll contact you to arrange a back-order or refund — whichever you prefer.
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