Send firm hydraulic pressure to your rear drum shoes with the Dorman First Stop Drum Brake Wheel Cylinder, part number W37851. It drops in as a direct-fit rear wheel cylinder for the 1990-1993 Geo Storm (All engines), which uses two per axle — so plan on replacing both sides as a matched pair.
Mounted at the drum backing plate, a wheel cylinder converts brake-line hydraulic pressure into outward force that pushes the brake shoes against the drum. Dorman engineered this unit as a direct replacement built to drop in like the original cylinder on the listed applications, and it is manufactured and tested for quality assurance.
- Cast iron body: a cast iron housing forms the pressure bore.
- EPDM rubber cups and boots: made with high-quality EPDM rubber cups and boots for long-lasting performance.
- Surface-tested bore: the wheel cylinder bore is surface-tested to provide an optimum sealing surface for the pressure cups.
- Bleeder screw included: a bleeder screw is included; a bleeder screw cap is not included.
- Sizing: 0.625 in inside diameter with an M10 x 1.0 inlet thread (10 mm thread diameter, 1.0 pitch).
Signs a wheel cylinder may need replacing include brake fluid weeping at the backing plate, a soft or sinking pedal, or uneven rear braking; if a leaking or seized cylinder is the cause, this replaces it. Country of origin: China.
Interchange: 18E314 · 84-10007 · 8410007 · W906647 · 101-1176 · 1011176 · W-50007 · W50007 · 072-8739 · 0728739 · 34070 · 134.43007 · 135.43007 · WC14070 · 375-50000 · 37550000 · 94362829 · 8943628290 · 2037851 · WC37851 · F120218 · WC120218 · Manufacturer part number W37851.
This part cross-references / interchanges with the following part numbers:
18E314, 84-10007, W906647, 101-1176, W-50007, 072-8739, 34070, 134.43007, 135.43007, WC14070, 375-50000, 94362829, 8943628290, WC37851, F120218, WC120218
Frequently Asked Questions
Will this fit my vehicle?
It's a direct-fit rear drum brake wheel cylinder for the 1990-1993 Geo Storm (All engines). Check the "Vehicles it fits" section to confirm it matches your vehicle.
How many do I need?
The Geo Storm uses two rear wheel cylinders. This listing is for one, so order two to replace both sides together as a matched pair for balanced braking.
Does it include a bleeder screw?
Yes, a bleeder screw is included. A bleeder screw cap is not included.
What does a wheel cylinder do?
It converts brake-line hydraulic pressure into outward force that pushes the drum brake shoes against the drum during braking.
What are its key specifications?
A cast iron body with high-quality EPDM rubber cups and boots, a 0.625 in inside diameter bore, and an M10 x 1.0 inlet thread. Country of origin: China.
