A-Premium Rear Drum Brake Wheel Cylinder — 1.188in Bore Cast-Iron Direct-Fit for Chevy & GMC

The A-Premium Rear Drum Brake Wheel Cylinder is a direct-fit, cast-iron replacement wheel cylinder for many Chevy and GMC trucks and SUVs with a 1.188" bore, designed to restore rear drum braking function.

This wheel cylinder is a straightforward OE-style replacement built from cast iron, with a 1.188 inch inside diameter and 3/8-24 inlet thread size. It fits a wide range of Chevrolet and GMC models across the 1970s through the early 2000s — including C10, C1500, K1500, Suburban, Tahoe, Yukon and Blazer variants — and is supplied with the bleeder screw but without a protective bleeder cap. Use the vehicle selector at the top of the listing and check special notes to confirm fitment for left or right rear installations before ordering.

Which vehicles will this A-Premium wheel cylinder work on?

This cylinder covers many Chevrolet and GMC rear drum brake applications from the mid-1970s to 2000. Fit varies by model year, brake diameter, and suspension or cab configuration; always verify with your vehicle information.

• Chevrolet: Blazer (1992–1994), C10 series (1974–1986 variations listed), C1500/K1500 (1988–1999 depending on brake size)
• GMC: C15/C1500 (1974–1991 variants), K1500 and K1500 Suburban (1988–1999), Yukon (1992–2000)
• Reference OEM/aftermarket numbers: W37785, 18013956, 18018788, 18060167, 19213347

What are the key mechanical specifications and hardware included?

Know the precise dimensions and hardware before you buy — this avoids returns and ensures safe brake operation. The part is built to match common OE dimensions for drum brake wheel cylinders used on the listed vehicles.

• Inside diameter (bore): 1.188 inches — matches original specification for applicable models
• Brake component inlet thread: 3/8-24 inch; thread diameter: 3/8
• Material: durable cast iron body for long-term service life
• Hardware: bleeder screw included; bleeder screw cap not included

How do I install and verify this wheel cylinder on my vehicle?

Installation follows standard drum brake service procedures: remove the drum, disconnect the brake line, unbolt the old cylinder, transfer or replace hardware, and bleed the brake system fully. If you are unsure, consult a service manual or a professional mechanic.

• Confirm left/right fitment using vehicle selector and special notes before removing the old part
• Use correct brake line wrench to avoid rounding the 3/8-24 inlet fitting
• After installation, bleed brakes until firm pedal and check for leaks at threads and bleeder screw
• Torque mounting hardware to manufacturer specs and inspect drum and shoes for wear

What should I check before ordering this replacement part?

Double-check compatibility with your vehicle’s model year, axle/brake size, and cab/suspension configuration to ensure a proper fit. Mismatched cylinders can cause leaks, poor braking, or installation issues.

• Enter vehicle year, make, model, and axle information into the fitment tool on the listing
• Compare bore size (1.188") and inlet thread (3/8-24) with the old cylinder
• Verify whether you need left or right side (driver/passenger) and rear-specific fitment
• Inspect drums, shoes, and wheel bearings while replacing the cylinder for best results

Who this is for: This A-Premium rear drum wheel cylinder is intended for DIY mechanics and professional technicians restoring older Chevrolet and GMC trucks or SUVs that use 10–inch style rear drum brakes or the listed factory configurations. It’s suitable when you need a dependable cast-iron replacement that matches OE dimensions and includes the bleeder screw for straightforward installation — as long as you confirm vehicle fitment and follow proper brake bleeding and safety procedures.