Homeβ€Ί Brake > Hardware, Fasteners and Fittingsβ€Ί Dorman 42040 Brake Master Cylinder Reservoir Cap
Part #: 42040

Dorman 42040 Brake Master Cylinder Reservoir Cap

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408 vehicles fit this part
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OE Direct Replacement β€” Bolt-on fit, no modifications needed
Fitment: Cadillac, Chevrolet, GMC, Dodge, Buick, Oldsmobile, and Pontiac, Escalade, C2500, K2500, Suburban 2500, Tahoe, Yukon, Yukon XL 2500, C1500 Suburban, C2500 Suburban, K1500 Suburban, K2500 Suburban, C1500, K1500, Ram 1500, Ram 2500, Blazer, C3500, K3500, Electra, LeSabre, Reatta, Riviera, DeVille, Eldorado, Seville, 98, Delta 88, Toronado, Bonneville, Fleetwood, Century, Skyhawk, Skylark, Somerset, Cimarron, Cavalier, Celebrity, Calais, Cutlass Ciera, Firenza, 6000, Grand Am, Sunbird, Somerset Regal, Citation II, J2000 Sunbird, Omega, Phoenix, Citation, J2000, Regal, El Camino, Malibu, Monte Carlo, Caballero, Cutlass, Cutlass Calais, Cutlass Cruiser, Cutlass Supreme, Grand LeMans, Grand Prix, and LeMans
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Overview of Dorman Brake Master Cylinder Reservoir Cap 42040

The Dorman 42040 brake master cylinder reservoir cap is a durable replacement part designed for select Buick, Cadillac, Chevrolet, Dodge, GMC, Oldsmobile, and Pontiac vehicles. Made from sturdy plastic with a rectangular shape, this cap provides a reliable seal for the brake fluid reservoir without requiring an additional gasket or seal.

  • Constructed from high-quality plastic for durability
  • Rectangular shape designed to match original equipment
  • No gasket or seal required for installation
  • Includes one brake master cylinder reservoir cap per package
  • Compatible with multiple GM and Dodge models including Blazer, Tahoe, C1500, and Bonneville

Product Details and Specifications

The Dorman 42040 brake master cylinder reservoir cap is engineered to meet or exceed OEM specifications for a secure fit and proper function. Its plastic construction resists corrosion and wear, ensuring long-lasting performance in the brake system. The rectangular design matches the original cap shape found on many GM trucks and cars such as the Chevrolet Blazer, GMC Sierra models, and Cadillac DeVille. This cap does not include a gasket or seal, as it is designed to seal effectively without one, simplifying installation and maintenance.

Compatible Vehicles and Applications

This brake master cylinder reservoir cap is compatible with a wide range of vehicles, including but not limited to:

  • Buick Century, LeSabre, and Regal
  • Cadillac DeVille, Eldorado, and Seville
  • Chevrolet Blazer, C1500, Suburban, Tahoe, and Malibu
  • Dodge Ram 1500 and 2500
  • GMC Sierra 1500, 2500, 3500, and Yukon models
  • Oldsmobile Cutlass, Calais, and 98
  • Pontiac Grand Prix, Bonneville, and Firebird

Common Issues Addressed by This Reservoir Cap

  • Preventing brake fluid contamination from dirt and moisture
  • Maintaining proper brake fluid pressure and system integrity
  • Replacing cracked or damaged original reservoir caps
  • Eliminating brake fluid leaks around the master cylinder reservoir
  • Ensuring a secure seal without the need for additional gaskets

Installation Notes and Tips

Installation of the Dorman 42040 brake master cylinder reservoir cap is straightforward. Before installing, clean the reservoir opening to remove any debris or old fluid residue. Align the rectangular cap carefully and press down firmly until it seats securely. Since no gasket or seal is required, ensure the cap is fully seated to prevent leaks. Check brake fluid levels after installation and top off if necessary. This part is designed for direct replacement on compatible Buick, Cadillac, Chevrolet, Dodge, GMC, Oldsmobile, and Pontiac models.

Quality Assurance and Warranty

Dorman parts are manufactured to meet industry standards for quality and reliability. The 42040 brake master cylinder reservoir cap undergoes rigorous testing to ensure proper fit and function. While specific warranty details may vary, Dorman typically offers limited warranties covering defects in material and workmanship. Refer to Dorman’s official documentation for exact warranty terms applicable to this part.

BrandDorman
Part Number42040
Gasket Or Seal IncludedNo
MaterialPlastic
Package Contents1 Brake Master Cylinder Cap
Seal IncludedNot Required
ShapeRectangular

This part fits 408 vehicles. Search below:

YearMakeModelDrive TypePositionNotes
2000CadillacEscaladeN/A
2000ChevroletC2500N/A
2000ChevroletK2500N/A
2000ChevroletSuburban 2500N/A
2000ChevroletTahoeN/A
2000GMCC2500N/A
2000GMCK2500N/A
2000GMCYukonN/A
2000GMCYukon XL 2500N/A
1999CadillacEscaladeN/A
1999ChevroletC1500 SuburbanN/A
1999ChevroletC2500N/A
1999ChevroletC2500 SuburbanN/A
1999ChevroletK1500 SuburbanN/A
1999ChevroletK2500N/A
1999ChevroletK2500 SuburbanN/A
1999ChevroletTahoeN/A
1999GMCC1500 SuburbanN/A
1999GMCC2500N/A
1999GMCC2500 SuburbanN/A
1999GMCK1500 SuburbanN/A
1999GMCK2500N/A
1999GMCK2500 SuburbanN/A
1999GMCYukonN/A
1998ChevroletC1500N/A
1998ChevroletC1500 SuburbanN/A
1998ChevroletC2500N/A
1998ChevroletC2500 SuburbanN/A
1998ChevroletK1500N/A
1998ChevroletK1500 SuburbanN/A
1998ChevroletK2500N/A
1998ChevroletK2500 SuburbanN/A
1998ChevroletTahoeN/A
1998GMCC1500N/A
1998GMCC1500 SuburbanN/A
1998GMCC2500N/A
1998GMCC2500 SuburbanN/A
1998GMCK1500N/A
1998GMCK1500 SuburbanN/A
1998GMCK2500N/A
1998GMCK2500 SuburbanN/A
1998GMCYukonN/A
1997ChevroletC1500N/A
1997ChevroletC1500 SuburbanN/A
1997ChevroletC2500N/A
1997ChevroletC2500 SuburbanN/A
1997ChevroletK1500N/A
1997ChevroletK1500 SuburbanN/A
1997ChevroletK2500N/A
1997ChevroletK2500 SuburbanN/A
1997ChevroletTahoeN/A
1997DodgeRam 1500N/A
1997DodgeRam 2500RWDN/A
1997DodgeRam 25004WDN/A7,500 Lb. GVW
1997GMCC1500N/A
1997GMCC1500 SuburbanN/A
1997GMCC2500N/A
1997GMCC2500 SuburbanN/A
1997GMCK1500N/A
1997GMCK1500 SuburbanN/A
1997GMCK2500N/A
1997GMCK2500 SuburbanN/A
1997GMCYukonN/A
1996ChevroletC1500N/A
1996ChevroletC1500 SuburbanN/A
1996ChevroletC2500N/A
1996ChevroletC2500 SuburbanN/A
1996ChevroletK1500N/A
1996ChevroletK1500 SuburbanN/A
1996ChevroletK2500N/A
1996ChevroletK2500 SuburbanN/A
1996ChevroletTahoeN/A
1996DodgeRam 1500N/A
1996DodgeRam 2500RWDN/A
1996DodgeRam 25004WDN/A7,500 Lb. GVW
1996GMCC1500N/A
1996GMCC1500 SuburbanN/A
1996GMCC2500N/A
1996GMCC2500 SuburbanN/A
1996GMCK1500N/A
1996GMCK1500 SuburbanN/A
1996GMCK2500N/A
1996GMCK2500 SuburbanN/A
1996GMCYukonN/A
1995ChevroletC1500N/A
1995ChevroletC1500 SuburbanN/A
1995ChevroletC2500N/A
1995ChevroletC2500 SuburbanN/A
1995ChevroletK1500N/A
1995ChevroletK1500 SuburbanN/A
1995ChevroletK2500N/A
1995ChevroletK2500 SuburbanN/A
1995ChevroletTahoeN/A
1995DodgeRam 1500N/A
1995DodgeRam 2500RWDN/A
1995DodgeRam 25004WDN/A7,500 Lb. GVW
1995GMCC1500N/A
1995GMCC1500 SuburbanN/A
1995GMCC2500N/A
1995GMCC2500 SuburbanN/A
1995GMCK1500N/A
1995GMCK1500 SuburbanN/A
1995GMCK2500N/A
1995GMCK2500 SuburbanN/A
1995GMCYukonN/A
1994ChevroletBlazerN/A
1994ChevroletC1500N/A
1994ChevroletC1500 SuburbanN/A
1994ChevroletC2500N/A
1994ChevroletC2500 SuburbanN/A
1994ChevroletC3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1994ChevroletK1500N/A
1994ChevroletK1500 SuburbanN/A
1994ChevroletK2500N/A
1994ChevroletK2500 SuburbanN/A
1994ChevroletK3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1994DodgeRam 1500N/A
1994DodgeRam 2500RWDN/A
1994DodgeRam 25004WDN/A7,500 Lb. GVW
1994GMCC1500N/A
1994GMCC1500 SuburbanN/A
1994GMCC2500N/A
1994GMCC2500 SuburbanN/A
1994GMCC3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1994GMCK1500N/A
1994GMCK1500 SuburbanN/A
1994GMCK2500N/A
1994GMCK2500 SuburbanN/A
1994GMCK3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1994GMCYukonN/A
1993ChevroletBlazerN/A
1993ChevroletC1500N/A
1993ChevroletC1500 SuburbanN/A
1993ChevroletC2500N/A
1993ChevroletC2500 SuburbanN/A
1993ChevroletC3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1993ChevroletK1500N/A
1993ChevroletK1500 SuburbanN/A
1993ChevroletK2500N/A
1993ChevroletK2500 SuburbanN/A
1993ChevroletK3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1993GMCC1500N/A
1993GMCC1500 SuburbanN/A
1993GMCC2500N/A
1993GMCC2500 SuburbanN/A
1993GMCC3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1993GMCK1500N/A
1993GMCK1500 SuburbanN/A
1993GMCK2500N/A
1993GMCK2500 SuburbanN/A
1993GMCK3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1993GMCYukonN/A
1992ChevroletBlazerN/A
1992ChevroletC1500N/A
1992ChevroletC1500 SuburbanN/A
1992ChevroletC2500N/A
1992ChevroletC2500 SuburbanN/A
1992ChevroletC3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1992ChevroletK1500N/A
1992ChevroletK1500 SuburbanN/A
1992ChevroletK2500N/A
1992ChevroletK2500 SuburbanN/A
1992ChevroletK3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1992GMCC1500N/A
1992GMCC1500 SuburbanN/A
1992GMCC2500N/A
1992GMCC2500 SuburbanN/A
1992GMCC3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1992GMCK1500N/A
1992GMCK1500 SuburbanN/A
1992GMCK2500N/A
1992GMCK2500 SuburbanN/A
1992GMCK3500N/ARear Drum Brakes or Single Rear Wheel (SRW)
1992GMCYukonN/A
1991ChevroletC1500N/A
1991ChevroletC2500N/A
1991ChevroletC3500N/ARear Drum Brakes
1991ChevroletK1500N/A
1991ChevroletK2500N/A
1991ChevroletK3500N/ARear Drum Brakes
1991GMCC1500N/A
1991GMCC2500N/A
1991GMCC3500N/ARear Drum Brakes
1991GMCK1500N/A
1991GMCK2500N/A
1991GMCK3500N/ARear Drum Brakes
1990BuickLeSabreN/A
1990BuickReattaN/A
1990BuickRivieraN/A
1990CadillacDeVilleN/A
1990CadillacEldoradoN/A
1990CadillacSevilleN/A
1990ChevroletC1500N/A
1990ChevroletC2500N/A
1990ChevroletC3500N/ARear Drum Brakes
1990ChevroletK1500N/A
1990ChevroletK2500N/A
1990ChevroletK3500N/ARear Drum Brakes
1990GMCC1500N/A
1990GMCC2500N/A
1990GMCC3500N/ARear Drum Brakes
1990GMCK1500N/A
1990GMCK2500N/A
1990GMCK3500N/ARear Drum Brakes
1990Oldsmobile98N/A
1990OldsmobileDelta 88N/A
1990OldsmobileToronadoN/A
1990PontiacBonnevilleN/A
1989BuickLeSabreN/A
1989BuickReattaN/A
1989BuickRivieraN/A
1989CadillacDeVilleN/A
1989CadillacEldoradoN/A
1989CadillacFleetwoodN/A
1989CadillacSevilleN/A
1989ChevroletC1500N/A
1989ChevroletC2500N/A
1989ChevroletC3500N/ARear Drum Brakes
1989ChevroletK1500N/A
1989ChevroletK2500N/A
1989ChevroletK3500N/ARear Drum Brakes
1989GMCC1500N/A
1989GMCC2500N/A
1989GMCC3500N/ARear Drum Brakes
1989GMCK1500N/A
1989GMCK2500N/A
1989GMCK3500N/ARear Drum Brakes
1989Oldsmobile98N/A
1989OldsmobileDelta 88N/A
1989OldsmobileToronadoN/A
1989PontiacBonnevilleN/A
1988BuickLeSabreN/A
1988BuickReattaN/A
1988BuickRivieraN/A
1988CadillacDeVilleN/A
1988CadillacEldoradoN/A
1988CadillacFleetwoodN/A
1988CadillacSevilleN/A
1988ChevroletC1500N/A
1988ChevroletC2500N/A
1988ChevroletC3500N/ARear Drum Brakes
1988ChevroletK1500N/A
1988ChevroletK2500N/A
1988ChevroletK3500N/ARear Drum Brakes
1988GMCC1500N/A
1988GMCC2500N/A
1988GMCC3500N/ARear Drum Brakes
1988GMCK1500N/A
1988GMCK2500N/A
1988GMCK3500N/ARear Drum Brakes
1988Oldsmobile98N/A
1988OldsmobileDelta 88N/A
1988OldsmobileToronadoN/A
1988PontiacBonnevilleN/A
1987BuickLeSabreN/A
1987BuickRivieraN/A
1987CadillacDeVilleN/A
1987CadillacEldoradoN/A
1987CadillacFleetwoodN/A
1987CadillacSevilleN/A
1987Oldsmobile98N/A
1987OldsmobileDelta 88N/A
1987OldsmobileToronadoN/A
1987PontiacBonnevilleN/A
1986BuickCenturyN/A
1986BuickLeSabreN/A
1986BuickRivieraN/A
1986BuickSkyhawkN/A
1986BuickSkylarkN/A
1986CadillacCimarronN/A
1986CadillacDeVilleN/A
1986CadillacEldoradoN/A
1986CadillacFleetwoodFWDN/A
1986CadillacSevilleN/A
1986ChevroletCavalierN/A
1986ChevroletCelebrityN/A
1986Oldsmobile98N/A
1986OldsmobileCalaisN/A
1986OldsmobileCutlass CieraN/A
1986OldsmobileDelta 88N/A
1986OldsmobileFirenzaN/A
1986OldsmobileToronadoN/A
1986Pontiac6000N/A
1986PontiacGrand AmN/A
1986PontiacSunbirdN/A
1985BuickCenturyN/A
1985BuickSkyhawkN/A
1985BuickSkylarkN/A
1985CadillacCimarronN/A
1985CadillacDeVilleN/A
1985CadillacFleetwoodFWDN/A
1985ChevroletCavalierN/A
1985ChevroletCelebrityN/A
1985ChevroletCitation IIN/A
1985Oldsmobile98N/A
1985OldsmobileCalaisN/A
1985OldsmobileCutlass CieraN/A
1985OldsmobileFirenzaN/A
1985Pontiac6000N/A
1985PontiacGrand AmN/A
1985PontiacJ2000 SunbirdN/A
1984BuickCenturyN/A
1984BuickSkyhawkN/A
1984BuickSkylarkN/A
1984CadillacCimarronN/A
1984ChevroletCavalierN/A
1984ChevroletCelebrityN/A
1984ChevroletCitation IIN/A
1984OldsmobileCutlass CieraN/A
1984OldsmobileFirenzaN/A
1984OldsmobileOmegaN/A
1984Pontiac6000N/A
1984PontiacJ2000 SunbirdN/A
1984PontiacPhoenixN/A
1983BuickCenturyN/A
1983BuickSkyhawkN/A
1983BuickSkylarkN/A
1983CadillacCimarronN/A
1983ChevroletCavalierN/A
1983ChevroletCelebrityN/A
1983ChevroletCitationN/A
1983OldsmobileCutlass CieraN/A
1983OldsmobileFirenzaN/A
1983OldsmobileOmegaN/A
1983Pontiac6000N/A
1983PontiacJ2000N/A
1983PontiacPhoenixN/A
1982BuickCenturyN/A
1982BuickSkyhawkN/A
1982BuickSkylarkN/A
1982CadillacCimarronN/A
1982ChevroletCavalierN/A
1982ChevroletCelebrityN/A
1982ChevroletCitationN/A
1982OldsmobileCutlass CieraN/A
1982OldsmobileFirenzaN/A
1982OldsmobileOmegaN/A
1982Pontiac6000N/A
1982PontiacJ2000N/A
1982PontiacPhoenixN/A
1981BuickCenturyN/A
1981BuickRegalN/A
1981BuickRivieraN/A
1981BuickSkylarkN/A
1981CadillacEldoradoN/A
1981CadillacSevilleN/A
1981ChevroletCitationN/A
1981ChevroletEl CaminoN/A
1981ChevroletMalibuN/A
1981ChevroletMonte CarloN/A
1981OldsmobileCutlassN/A
1981OldsmobileCutlass CalaisN/A
1981OldsmobileCutlass CruiserN/A
1981OldsmobileCutlass SupremeN/A
1981OldsmobileOmegaN/A
1981OldsmobileToronadoN/A
1981PontiacGrand LeMansN/A
1981PontiacGrand PrixN/A
1981PontiacLeMansN/A
1981PontiacPhoenixN/A
1980BuickCenturyN/A
1980BuickRegalN/A
1980BuickRivieraN/A
1980BuickSkylarkN/A
1980CadillacEldoradoN/A
1980CadillacSevilleN/A
1980ChevroletCitationN/A
1980ChevroletEl CaminoN/A
1980ChevroletMalibuN/A
1980ChevroletMonte CarloN/A
1980OldsmobileCutlassN/A
1980OldsmobileCutlass CalaisN/A
1980OldsmobileCutlass CruiserN/A
1980OldsmobileCutlass SupremeN/A
1980OldsmobileOmegaN/A
1980OldsmobileToronadoN/A
1980PontiacGrand AmN/A
1980PontiacGrand LeMansN/A
1980PontiacGrand PrixN/A
1980PontiacLeMansN/A
1980PontiacPhoenixN/A
1979BuickCenturyN/A
1979BuickRegalN/A
1979BuickRivieraN/A
1979CadillacEldoradoN/A
1979ChevroletEl CaminoN/A
1979ChevroletMalibuN/A
1979ChevroletMonte CarloN/A
1979OldsmobileCutlassN/A
1979OldsmobileCutlass CalaisN/A
1979OldsmobileCutlass SupremeN/A
1979OldsmobileToronadoN/A
1979PontiacGrand AmN/A
1979PontiacGrand LeMansN/A
1979PontiacGrand PrixN/A
1979PontiacLeMansN/A
1978BuickCenturyN/A
1978BuickRegalN/A
1978ChevroletEl CaminoN/A
1978ChevroletMalibuN/A
1978ChevroletMonte CarloN/A
1978OldsmobileCutlassN/A
1978OldsmobileCutlass CalaisN/A
1978OldsmobileCutlass SupremeN/A
1978PontiacGrand AmN/A
1978PontiacGrand LeMansN/A
1978PontiacGrand PrixN/A
1978PontiacLeMansN/A

* Always verify fitment with your vehicle's VIN if unsure. Submodel & trim restrictions may apply.

This part directly replaces or is cross-referenced with the following part numbers:

18002375420404

Cross-reference numbers are provided for identification purposes only. Always confirm fitment before ordering.