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ACDelco 18M938 Brake Master Cylinder

ACDelco 18M938 Brake Master Cylinder Image 1
ACDelco 18M938 Brake Master Cylinder Image 2
ACDelco 18M938 Brake Master Cylinder Image 3
ACDelco 18M938 Brake Master Cylinder Image 4
ACDelco 18M938 Brake Master Cylinder Image 5
ACDelco 18M938 Brake Master Cylinder Image 6
ACDelco 18M938 Brake Master Cylinder Image 7
ACDelco 18M938 Brake Master Cylinder Image 8
ACDelco 18M938 Brake Master Cylinder

ACDelco
Brand:ACDelco
Part Number: 18M938
UPC: 00707773315354
Weight: 4.77 lbs
Condition:New



On Sale:

$54.33

Availability:
10 in Stock
Warehouse: US-4
Quantity:

Product Information

Description:

CYLINDER B (B)

ACDelco Professional Brake Master Cylinders use both aluminum and iron castings, making them a high quality replacement for many vehicles on the road today. These master cylinders contain both Ethylene Propylene (EPDM) and Styrene Butadiene (SBR) rubber components to provide superior resistance to heat, corrosion, and leakage. ACDelco Professional Brake Master Cylinders are ready to bench bleed and install right out of the box - no assembly required. These premium aftermarket replacement brake master cylinders are manufactured to meet your expectations for fit, form, and function. ⚠ WARNING: Cancer and Reproductive Harm - https://www.P65Warnings.ca.gov

Features and Benefits:

  • Cast iron and aluminum specifications; no extra stress on the brake boosting mounting
  • Geometrical tolerance ensures that the body and plastic reservoir match for a proper fit
  • Meets the brake performance requirements of SAE J1153 and J1154 testing, providing reliability and quality
  • Piston assembly and return spring help to prevent brake drag, which can cause premature brake pad wear
  • Pressure tested to ensure safe and confident braking

Specifications:

Bleeder Hoses Included:
Yes
Bore Size:
1.000 in.
Brake Booster Included:
No
Height (in):
4.8 in
Length (in):
9.4 in
Master Cylinder Bore Diameter:
1 in.
Master Cylinder Bore Diameter:
25.4 mm
Master Cylinder Cap Included:
Yes
Master Cylinder Material:
Iron
Mounting Bracket Included:
No
Mounting Hole Diameter:
0.413 in.
Mounting Hole Quantity:
2
Port Quantity:
3
Primary Outlet Thread Diameter:
0.437 in.
Primary Outlet Thread Diameter:
11.112 mm
Programming Required:
No
Push Rod Included:
No
Reservoir Included:
Yes
Weight (lb):
4.77 lb
Width (in):
5.8 in

Features and Benefits:

  • – Calipers and wheel cylinders should be checked every brake inspection and serviced or replaced as required.
  • – Check brake fluid level at every oil change. Replace fluid according to owner's manual recommendations.
  • – Check the thickness of your brake pads.
  • – Inspect the brake lines for rust, punctures, or visible leaks (You may be able to do this, but consult a qualified technician if necessary).
  • – Inspection of brake lining and pads for wear or contamination by brake fluid or grease.
  • – Inspection of the brake hoses for brittleness or cracking.
  • – Inspection of wheel bearings and grease seals.
  • – Parking brake adjustments (as needed).
  • The following inspections and maintenance procedures can help prevent potential brake problems:
  • The following should be conducted by a qualified technician:

Specifications:

Country of Origin:
CN

Select a vehicle to narrow ACDelco 18M938 Brake Master Cylinder fitment info!

Last Updated: 03/09/2024

Years Vehicle Per Vehicle Fit NotesFitment Notes
Chevrolet Bel Air

7.0L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Bel Air



7.0L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Bel Air

4.1L L6 Gas OHV,
6.5L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Bel Air



4.1L L6 Gas OHV,
6.5L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Bel Air

4.6L V8 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Bel Air



4.6L V8 Gas OHV,
5.3L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Bel Air

3.8L L6 Gas OHV,
6.7L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Bel Air



3.8L L6 Gas OHV,
6.7L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Bel Air

7.0L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Bel Air



7.0L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Biscayne

7.0L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Biscayne



7.0L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Biscayne

4.1L L6 Gas OHV,
6.5L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Biscayne



4.1L L6 Gas OHV,
6.5L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Biscayne

4.6L V8 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Biscayne



4.6L V8 Gas OHV,
5.3L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Biscayne

3.8L L6 Gas OHV,
6.7L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Biscayne



3.8L L6 Gas OHV,
6.7L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Biscayne

7.0L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Biscayne



7.0L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet C20 Pickup

4.1L L6 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
with Round Reservoir
 

Chevrolet C20 Pickup



4.1L L6 Gas OHV,
5.3L V8 Gas OHV Professional
with Round Reservoir

1 Per Vehicle
Chevrolet C20 Pickup

4.6L V8 Gas OHV,
4.8L L6 Gas OHV
1
 
Professional
with Round Reservoir
 

Chevrolet C20 Pickup



4.6L V8 Gas OHV,
4.8L L6 Gas OHV Professional
with Round Reservoir

1 Per Vehicle
Chevrolet C20 Pickup

3.8L L6 Gas OHV
1
 
Professional
with Round Reservoir
 

Chevrolet C20 Pickup



3.8L L6 Gas OHV Professional
with Round Reservoir

1 Per Vehicle
Chevrolet Caprice

4.6L V8 Gas OHV,
5.3L V8 Gas OHV,
6.5L V8 Gas OHV,
7.0L V8 Gas OHV
1
 
Professional
Except Heavy Duty Brakes
 

Chevrolet Caprice



4.6L V8 Gas OHV,
5.3L V8 Gas OHV,
6.5L V8 Gas OHV,
7.0L V8 Gas OHV Professional
Except Heavy Duty Brakes

1 Per Vehicle
Chevrolet Chevelle

3.2L L6 Gas,
4.6L V8 Gas,
6.5L V8 Gas OHV
1
 
Professional
1 Bore Diameter
 

Chevrolet Chevelle



3.2L L6 Gas,
4.6L V8 Gas,
6.5L V8 Gas OHV Professional
1 Bore Diameter

1 Per Vehicle
Chevrolet Chevelle

3.2L L6 Gas OHV,
3.8L L6 Gas OHV,
4.6L V8 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
1 Bore Diameter
 

Chevrolet Chevelle



3.2L L6 Gas OHV,
3.8L L6 Gas OHV,
4.6L V8 Gas OHV,
5.3L V8 Gas OHV Professional
1 Bore Diameter

1 Per Vehicle
Chevrolet Chevelle

3.8L L6 Gas,
5.4L V8 Gas OHV
1
 
Professional
1 Bore Diameter
 

Chevrolet Chevelle



3.8L L6 Gas,
5.4L V8 Gas OHV Professional
1 Bore Diameter

1 Per Vehicle
Chevrolet Chevy II

5.3L V8 Gas OHV,
5.4L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Chevy II



5.3L V8 Gas OHV,
5.4L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Chevy II

3.2L L6 Gas,
3.8L L6 Gas,
3.8L L6 Gas OHV,
4.6L V8 Gas
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Chevy II



3.2L L6 Gas,
3.8L L6 Gas,
3.8L L6 Gas OHV,
4.6L V8 Gas Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Chevy II

4.6L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Chevy II



4.6L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Chevy II

2.5L L4 Gas OHV,
3.2L L6 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Chevy II



2.5L L4 Gas OHV,
3.2L L6 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet El Camino

6.5L V8 Gas OHV
1
 
Professional
Except Metallic Lining
 

Chevrolet El Camino



6.5L V8 Gas OHV Professional
Except Metallic Lining

1 Per Vehicle
Chevrolet El Camino

3.2L L6 Gas OHV,
3.8L L6 Gas OHV,
4.6L V8 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
Except Metallic Lining
 

Chevrolet El Camino



3.2L L6 Gas OHV,
3.8L L6 Gas OHV,
4.6L V8 Gas OHV,
5.3L V8 Gas OHV Professional
Except Metallic Lining

1 Per Vehicle
Chevrolet G10 Van

3.8L L6 Gas
1
 
Professional
 

Chevrolet G10 Van



3.8L L6 Gas Professional

1 Per Vehicle
Chevrolet G10 Van

3.2L L6 Gas
1
 
Professional
 

Chevrolet G10 Van



3.2L L6 Gas Professional

1 Per Vehicle
Chevrolet G10 Van

2.5L L4 Gas
1
 
Professional
 

Chevrolet G10 Van



2.5L L4 Gas Professional

1 Per Vehicle
Chevrolet G10 Van

2.5L L4 Gas OHV
1
 
Professional
 

Chevrolet G10 Van



2.5L L4 Gas OHV Professional

1 Per Vehicle
Chevrolet Impala

4.6L V8 Gas,
7.0L V8 Gas,
7.0L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Impala



4.6L V8 Gas,
7.0L V8 Gas,
7.0L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Impala

4.1L L6 Gas OHV,
6.5L V8 Gas,
6.5L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Impala



4.1L L6 Gas OHV,
6.5L V8 Gas,
6.5L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Impala

5.4L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Impala



5.4L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Impala

4.6L V8 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Impala



4.6L V8 Gas OHV,
5.3L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Impala

3.8L L6 Gas,
6.7L V8 Gas
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Impala



3.8L L6 Gas,
6.7L V8 Gas Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Impala

3.8L L6 Gas OHV,
6.7L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Impala



3.8L L6 Gas OHV,
6.7L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Impala

4.6L V8 Gas
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Impala



4.6L V8 Gas Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet Impala

7.0L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Impala



7.0L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
Chevrolet K10 Pickup

4.1L L6 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
Except BENDIX Master Cylinder
 

Chevrolet K10 Pickup



4.1L L6 Gas OHV,
5.3L V8 Gas OHV Professional
Except BENDIX Master Cylinder

1 Per Vehicle
Chevrolet K10 Pickup

3.8L L6 Gas OHV,
4.6L V8 Gas OHV,
4.8L L6 Gas OHV
1
 
Professional
Except BENDIX Master Cylinder
 

Chevrolet K10 Pickup



3.8L L6 Gas OHV,
4.6L V8 Gas OHV,
4.8L L6 Gas OHV Professional
Except BENDIX Master Cylinder

1 Per Vehicle
Chevrolet K20 Pickup

4.1L L6 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
 

Chevrolet K20 Pickup



4.1L L6 Gas OHV,
5.3L V8 Gas OHV Professional

1 Per Vehicle
Chevrolet K20 Pickup

4.6L V8 Gas OHV,
4.8L L6 Gas OHV
1
 
Professional
 

Chevrolet K20 Pickup



4.6L V8 Gas OHV,
4.8L L6 Gas OHV Professional

1 Per Vehicle
Chevrolet K20 Pickup

3.8L L6 Gas OHV
1
 
Professional
 

Chevrolet K20 Pickup



3.8L L6 Gas OHV Professional

1 Per Vehicle
Chevrolet Malibu

3.2L L6 Gas OHV,
3.8L L6 Gas OHV,
4.6L V8 Gas OHV,
5.3L V8 Gas OHV,
6.5L V8 Gas OHV
1
 
Professional
Except Metallic Lining
1 Bore Diameter
 

Chevrolet Malibu



3.2L L6 Gas OHV,
3.8L L6 Gas OHV,
4.6L V8 Gas OHV,
5.3L V8 Gas OHV,
6.5L V8 Gas OHV Professional
Except Metallic Lining
1 Bore Diameter

1 Per Vehicle
GMC 1000

4.1L L6 Gas OHV,
5.0L V6 Gas OHV
1
 
Professional
 

GMC 1000



4.1L L6 Gas OHV,
5.0L V6 Gas OHV Professional

1 Per Vehicle
GMC 1000 Series

5.7L V6 Gas OHV
1
 
Professional
 

GMC 1000 Series



5.7L V6 Gas OHV Professional

1 Per Vehicle
GMC 1000 Series

3.8L L6 Gas OHV,
4.8L L6 Gas OHV,
5.0L V6 Gas OHV
1
 
Professional
 

GMC 1000 Series



3.8L L6 Gas OHV,
4.8L L6 Gas OHV,
5.0L V6 Gas OHV Professional

1 Per Vehicle
GMC 1500

4.1L L6 Gas OHV
1
 
Professional
 

GMC 1500



4.1L L6 Gas OHV Professional

1 Per Vehicle
GMC 1500 Series

5.7L V6 Gas OHV
1
 
Professional
 

GMC 1500 Series



5.7L V6 Gas OHV Professional

1 Per Vehicle
GMC 1500 Series

3.8L L6 Gas OHV,
4.8L L6 Gas OHV,
5.0L V6 Gas OHV
1
 
Professional
 

GMC 1500 Series



3.8L L6 Gas OHV,
4.8L L6 Gas OHV,
5.0L V6 Gas OHV Professional

1 Per Vehicle
GMC 2500

4.1L L6 Gas OHV
1
 
Professional
with Booster Brakes
 

GMC 2500



4.1L L6 Gas OHV Professional
with Booster Brakes

1 Per Vehicle
GMC 2500 Series

3.8L L6 Gas OHV,
4.8L L6 Gas OHV,
5.0L V6 Gas OHV,
5.7L V6 Gas OHV
1
 
Professional
with Booster Brakes
 

GMC 2500 Series



3.8L L6 Gas OHV,
4.8L L6 Gas OHV,
5.0L V6 Gas OHV,
5.7L V6 Gas OHV Professional
with Booster Brakes

1 Per Vehicle
GMC G1000 Series

2.5L L4 Gas OHV,
3.2L L6 Gas OHV,
3.8L L6 Gas OHV
1
 
Professional
w/o Brake Booster
 

GMC G1000 Series



2.5L L4 Gas OHV,
3.2L L6 Gas OHV,
3.8L L6 Gas OHV Professional
w/o Brake Booster

1 Per Vehicle
GMC I1000

4.1L L6 Gas OHV
1
 
Professional
 

GMC I1000



4.1L L6 Gas OHV Professional

1 Per Vehicle
GMC I1000

3.8L L6 Gas OHV
1
 
Professional
 

GMC I1000



3.8L L6 Gas OHV Professional

1 Per Vehicle
GMC I1500

4.1L L6 Gas OHV
1
 
Professional
 

GMC I1500



4.1L L6 Gas OHV Professional

1 Per Vehicle
GMC I1500

3.8L L6 Gas OHV
1
 
Professional
 

GMC I1500



3.8L L6 Gas OHV Professional

1 Per Vehicle
GMC I2500

4.1L L6 Gas OHV
1
 
Professional
with Booster Brakes
 

GMC I2500



4.1L L6 Gas OHV Professional
with Booster Brakes

1 Per Vehicle
GMC I2500

3.8L L6 Gas OHV
1
 
Professional
with Booster Brakes
 

GMC I2500



3.8L L6 Gas OHV Professional
with Booster Brakes

1 Per Vehicle
GMC K1000

5.0L V6 Gas OHV,
5.7L V6 Gas OHV
1
 
Professional
 

GMC K1000



5.0L V6 Gas OHV,
5.7L V6 Gas OHV Professional

1 Per Vehicle
GMC K1000 Pickup

5.0L V6 Gas
1
 
Professional
 

GMC K1000 Pickup



5.0L V6 Gas Professional

1 Per Vehicle
GMC K15/K1500 Pickup

5.0L V6 Gas OHV,
5.7L V6 Gas OHV
1
 
Professional
 

GMC K15/K1500 Pickup



5.0L V6 Gas OHV,
5.7L V6 Gas OHV Professional

1 Per Vehicle
GMC Suburban

4.1L L6 Gas OHV
1
 
Professional
 

GMC Suburban



4.1L L6 Gas OHV Professional

1 Per Vehicle
GMC Suburban

5.7L V6 Gas OHV
1
 
Professional
 

GMC Suburban



5.7L V6 Gas OHV Professional

1 Per Vehicle
GMC Suburban

2.5L L4 Gas OHV,
3.8L L6 Gas OHV,
4.8L L6 Gas OHV,
5.0L V6 Gas OHV
1
 
Professional
 

GMC Suburban



2.5L L4 Gas OHV,
3.8L L6 Gas OHV,
4.8L L6 Gas OHV,
5.0L V6 Gas OHV Professional

1 Per Vehicle
GMC Suburban

4.6L V8 Gas OHV
1
 
Professional
 

GMC Suburban



4.6L V8 Gas OHV Professional

1 Per Vehicle
Jeep Wagoneer

3.8L L6 Gas,
3.8L L6 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
with Single Piston Master Cylinder
 

Jeep Wagoneer



3.8L L6 Gas,
3.8L L6 Gas OHV,
5.3L V8 Gas OHV Professional
with Single Piston Master Cylinder

1 Per Vehicle
Jeep Wagoneer

3.8L L6 Gas OHV,
5.3L V8 Gas OHV
1
 
Professional
 

Jeep Wagoneer



3.8L L6 Gas OHV,
5.3L V8 Gas OHV Professional

1 Per Vehicle
Jeep Wagoneer

3.8L L6 Gas SOHC
1
 
Professional
 

Jeep Wagoneer



3.8L L6 Gas SOHC Professional

1 Per Vehicle
Pontiac Bonneville

6.4L V8 Gas,
6.4L V8 Gas OHV
1
 
Professional
Vehicles Built for Canadian Market
Except MORAINE Master Cylinder
Except BENDIX Master Cylinder
 

Pontiac Bonneville



6.4L V8 Gas,
6.4L V8 Gas OHV Professional
Vehicles Built for Canadian Market
Except MORAINE Master Cylinder
Except BENDIX Master Cylinder

1 Per Vehicle
Pontiac Grand Prix

6.4L V8 Gas OHV,
6.9L V8 Gas OHV
1
 
Professional
Vehicles Built for Canadian Market
Except MORAINE Master Cylinder
 

Pontiac Grand Prix



6.4L V8 Gas OHV,
6.9L V8 Gas OHV Professional
Vehicles Built for Canadian Market
Except MORAINE Master Cylinder

1 Per Vehicle
Pontiac Grand Prix

6.9L V8 Gas OHV
1
 
Professional
Except MORAINE Master Cylinder
 

Pontiac Grand Prix



6.9L V8 Gas OHV Professional
Except MORAINE Master Cylinder

1 Per Vehicle
Pontiac Grand Prix

6.4L V8 Gas OHV
1
 
Professional
Except MORAINE Master Cylinder
 

Pontiac Grand Prix



6.4L V8 Gas OHV Professional
Except MORAINE Master Cylinder

1 Per Vehicle
Pontiac Star Chief

6.4L V8 Gas OHV,
6.9L V8 Gas OHV
1
 
Professional
Vehicles Built for Canadian Market
 

Pontiac Star Chief



6.4L V8 Gas OHV,
6.9L V8 Gas OHV Professional
Vehicles Built for Canadian Market

1 Per Vehicle