Product Description
C4037X – MIDLAND FIRE-WALL MOUNT BOOSTER (GMC/CHEVY 1966–1970)
PART NUMBER(S):
Fleet Products: C4037X (Remanufactured) | OE (Midland): C4037N, C4074A, C4037P, C4074C
DESCRIPTION:
Model: Midland Vacuum Brake Booster (Firewall Mount)
Vehicles: GMC & Chevrolet trucks (1966–1970)
• Diameter: 11-11/16"
• Overall Length (with master cylinder): 23-7/16"
• Stud Size: 3/8-16 × 1-1/4"
• Stud Pattern: 3-3/4" × 3-3/4" (square)
• Mount Type: Firewall
Applications: Designed for 1966–1970 GMC and Chevrolet trucks (CE, SS, CS, EM, ES, EG 400/500/600 series). Confirmed in service documentation with C3492SX master cylinder. This booster uses the Midland square 3-3/4" × 3-3/4" stud pattern with extended 1-1/4" studs for firewall mounting.
CROSS-REFERENCE(S):
RV403701X, RVC4037LX, ZZRV403701X, C4037G, C4037H, C4037J, C4037K, C4037L, C4037M, C4037ML, 5396-RV403701X, 767653032474, C4074, HDX RV403701X, MBIRV403701X, MIDRV403701X,
RV403702X, RVC4037NX, ZZRV403702X, C4037MN, C4037N, C4074C, 5396-RV403702X, 665828, 767653032481, HDX RV403702X, MBIRV403702X, MIDRV403702X
A cross-reference listing means this part is a suitable replacement for the part numbers listed. Please confirm all ports and dimensions match your application before installing.
IMPORTANT INSTALLATION NOTES:
✔ Confirm 3-3/4" × 3-3/4" firewall stud pattern with 3/8-16 × 1-1/4" studs.
✔ Pair with C3492SX master cylinder for correct fitment on GMC/Chevy applications.
✔ Verify overall length (23-7/16") for clearance at firewall/cowl.
✔ Bench-bleed master before installation and bleed entire brake system after assembly.
SOLD AS REMANUFACTURED | CORE RETURN REQUIRED
Built to OEM standards | thoroughly cleaned, inspected, and tested to ensure durability, performance, and reliability in demanding applications.
SUPPORT & ORDERING
For technical support, installation guidance, or to confirm fitment, Call: 1-877-243-0442 | Email: sales@fleet-products.com
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