Check if this fits your car first
We can’t guarantee fitment or accept fitment returns without a vehicle selected.
Year
Make
Model
Trim
Engine
Check if this fits your vehicle
Select your vehicle details below
Select Year
Select Make
Select Model
Or call us at 888-477-2530 — we’ll help you out.
Check if this fitsShop worry-free by verifying fitment first. If the part doesn't fit, we'll make it right or refund you. Learn more
Main Image
Click to expand
Brake Master Cylinder Assembly
Authorized Dealer
Brake Master Cylinder Assembly
BrandGM Genuine PartsLearn More
Qty/Vehicle1
ConditionNew
Includes: (1) Brake Master Cylinder, Hardware
$000
•In Stock•Fast Shipping1
Estimated Delivery by calculating...
Calculating shipping time...
Ships to
Product Specifications
Features & Benefits
- •Direct OE fit - no modifications needed
- •Meets or exceeds manufacturer specs
- •24-month warranty included
- •Fast Shipping — ships same day before 3 PM ET
BrandGM Genuine Parts
Part Number18M391478
Part TypeBrake Master Cylinder
ConditionNew
Bleeder Hoses IncludedNo
Brake Booster IncludedNo
Compatibility
Vehicle Compatibility
Guaranteed to fit 0 vehicles from Infinity--Infinity
No compatibility data available
Frequently Asked Questions
We're always here to help. If you can't find your answer, ask Rydon - our AI assistant will help you out.
What vehicles does this Brake Master Cylinder fit?
This GM Genuine Parts Brake Master Cylinder (Part #18M391478) fits specific vehicles. Use the compatibility checker on this page to verify fitment for your vehicle.
Is this an OEM or aftermarket part?
This is a premium aftermarket Brake Master Cylinder by GM Genuine Parts, designed to meet or exceed OEM specifications with strict quality control standards.
What warranty is included?
This GM Genuine Parts Brake Master Cylinder is backed by a 24-month limited warranty covering defects in materials and workmanship from date of purchase.
How long does shipping take?
Fast shipping — orders before 3 PM ET ship the same day. Most arrive within 3-5 business days.
Can I return this if it does not fit?
30-day money-back guarantee. Return unused parts in original packaging for full refund.
Compatibility
Vehicle Compatibility
Guaranteed to fit 0 vehicles from Infinity--Infinity
No compatibility data available
Product Specifications
Brand
GM Genuine Parts
Part Type
Brake Master Cylinder
Brake Booster Included
No
Master Cylinder Cap Included
No
Part Number
18M391478
Bleeder Hoses Included
No
Length (In)
9.1 in
Master Cylinder Material
Aluminum
Bleeder Hoses IncludedNo
Brake Booster IncludedNo
Length (In)9.1 in
Master Cylinder Cap IncludedNo
Master Cylinder MaterialAluminum
Mounting Bracket IncludedNo
Mounting Hole Diameter0.342 IN
Reservoir IncludedNo
Bore Size (In)0.875 in
Faq - Answer 1No, but it is a good idea to inspect them for wear-out, cracking, leaking etc.
Faq - Answer 2Yes, ACDelco also offers GM OE brake cylinders.
Faq - Answer 3Yes, ACDelco Professional Brake Cylinders come with a 12 month / unlimited mile warranty.
Faq - Question 1Do I have to replace all my brake parts when replacing my brake cylinder?
Faq - Question 2Does ACDelco offer other grades of brake cylinders?
Faq - Question 3Are these brake parts durable?
Features Benefits - Bullet 1Meets the brake performance requirements of SAE J1153 and J1154 testing, providing reliability and quality
Features Benefits - Bullet 2Pressure tested to ensure safe and confident braking
Features Benefits - Bullet 3Cast iron and aluminum specifications; no extra stress on the brake boosting mounting
Features Benefits - Bullet 4Geometrical tolerance ensures that the body and plastic reservoir match for a proper fit
Features Benefits - Bullet 5Piston assembly and return spring help to prevent brake drag, which can cause premature brake pad wear
Good Maintenance Practices - Section 1 - Bullet 1Check brake fluid level at every oil change. Replace fluid according to owner's manual recommendations.
Good Maintenance Practices - Section 1 - Bullet 2Calipers and wheel cylinders should be checked every brake inspection and serviced or replaced as required.
Good Maintenance Practices - Section 1 - Bullet 3Inspect the brake lines for rust, punctures, or visible leaks (You may be able to do this, but consult a qualified technician if necessary).
Good Maintenance Practices - Section 1 - Bullet 4Check the thickness of your brake pads.
Good Maintenance Practices - Section 1 - HeaderThe following inspections and maintenance procedures can help prevent potential brake problems:
Good Maintenance Practices - Section 2 - Bullet 1Inspection of the brake hoses for brittleness or cracking.
Good Maintenance Practices - Section 2 - Bullet 2Inspection of brake lining and pads for wear or contamination by brake fluid or grease.
Good Maintenance Practices - Section 2 - Bullet 3Inspection of wheel bearings and grease seals.
Good Maintenance Practices - Section 2 - Bullet 4Parking brake adjustments (as needed).
Good Maintenance Practices - Section 2 - HeaderThe following should be conducted by a qualified technician:
Height (In)4.9 in
Mounting Hole Quantity2
Port Quantity2
Product DescriptionACDelco 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 Ethylen
Programming RequiredNo
Signs Of Wear Troubleshooting - Section 1 - Bullet 1Brake warning light is on.
Signs Of Wear Troubleshooting - Section 1 - Bullet 2Fluid spots beneath the car, indicating there may be a leak within the cylinder.
Signs Of Wear Troubleshooting - Section 1 - Bullet 3Difficulty stopping the vehicle.
Signs Of Wear Troubleshooting - Section 1 - Bullet 4A low or sinking brake pedal.
Signs Of Wear Troubleshooting - Section 1 - HeaderBrake cylinder signs of wear include:
Weight (Lb)1.4 lb
Width (In)5.3 in
Check if this fitsShop worry-free by verifying fitment first. If the part doesn't fit, we'll make it right or refund you. Learn more
Main Image
Click to expand
Brake Master Cylinder Assembly
Authorized Dealer
Call for Price
888-477-2530Our parts specialists are ready to help you find the best price.
Part #:18M391478
OE REPLACEMENT
Brake Master Cylinder Assembly
|
Part #:18M391478
|
Brake Master Cylinder
Call for Price
888-477-2530Our parts specialists are ready to help you find the best price.
Quantity:
1
In Stock·10 or more available
Fast delivery between Mon, Jun 22 to Mon, Jun 22
Ships To:Key Features
OEM-Equivalent QualityMeets/exceeds factory specs
American BusinessMaryland since 1986
24-Month WarrantyLimited coverage on every part
Fast Same Day ShippingWe ship all orders the same business day before cutoff
Product Specs
BrandGM Genuine Parts
Part Number18M391478
Part TypeBrake Master Cylinder
ConditionNew
Bleeder Hoses IncludedNo
Brake Booster IncludedNo
Length (In)9.1 in
Master Cylinder Cap IncludedNo
Compatibility
Vehicle Compatibility
Guaranteed to fit 0 vehicles from Infinity--Infinity
No compatibility data available
Questions & Answers
This GM Genuine Parts Brake Master Cylinder (Part #18M391478) fits specific vehicles. Use the compatibility checker on this page to verify fitment for your vehicle.
This is a premium aftermarket Brake Master Cylinder by GM Genuine Parts, designed to meet or exceed OEM specifications with strict quality control standards.
This GM Genuine Parts Brake Master Cylinder is backed by a 24-month limited warranty covering defects in materials and workmanship from date of purchase.
Fast shipping — orders before 3 PM ET ship the same day. Most arrive within 3-5 business days.
30-day money-back guarantee. Return unused parts in original packaging for full refund.
Have a Question?
Ask Marvin, our Car Expert
Offline
Things to Know
About This Brake Master Cylinder
This GM Genuine Parts automotive component is engineered to meet or exceed OEM specifications for reliable performance and long service life.
Key Features
- Meets or exceeds OEM specifications
- Direct-fit replacement design
- Rigorously tested for durability
- Professional-grade construction
- Backed by manufacturer warranty
Signs This Part Needs Replacement
- •Unusual noises from the component area
- •Decreased vehicle performance
- •Warning lights on dashboard
- •Visible wear or damage
- •Failed vehicle inspection
GM Genuine Parts
Trusted Automotive Brand
GM Genuine Parts is a trusted manufacturer of quality automotive parts.
View all GM Genuine Parts productsInstallation Guide
Moderate
1-3 hours
Tools Needed
Basic hand toolsTorque wrenchVehicle service manual
Frequently Asked Questions
WARNING: Handling passenger or off-highway motor vehicle parts can expose you to chemicals such as phthalates and lead, which are known to the State of California to cause cancer and reproductive harm. To minimize exposure, service the vehicle in a well-ventilated area, wear gloves, and wash your hands. For more information see www.P65Warnings.ca.gov/motor-vehicle-parts