Description
SB3030S2521 - 30/30 STD SPRING BRAKE W/21" PUSH ROD
PART NUMBER(S):
Fleet Products: SB3030S2521 | OE: 3431954, K121570 | Automann: 170.3030S2521
DESCRIPTION:
Model: 30/30 Standard Stroke Spring Brake
Vehicles: Freightliner, Kenworth, Peterbilt, International, Mack, Volvo, Western Star
• Type: 30/30 spring brake chamber (dual diaphragm)
• Stroke: 2.5"
• Push Rod: 21" length, 5/8"-18 UNF
• Ports: dual 3/8"-18 NPT
• Mounting: 2-stud, 5/8"-11 UNC
• Stud Spacing: ~4.75"
• Chamber Height: 9.25"
• Sealed spring chamber design
• Epoxy-coated, corrosion-resistant
• Breather tube design (severe service)
• Tamper-resistant, stroke alert compatible
Applications:
Designed for drive and trailer axles on severe-duty commercial trucks and trailers. Ideal for environments requiring extended rod lengths and high durability.
CROSS-REFERENCE(S):
3030S2521, SB3030S2521, 3030STD2521, 3431954, 3030TN2-2521, GC3030STD2521, R955207, K121570, E-11799, AS1142, P3030STD2521, 701075, KN31002, 90557159, 5050-3030STD21, 650-3030STD21, RA3030STD21, 7-3030STD21, 170.3030S2521, Silverback SB3030STD21, S-3030STD21, 3430051, 3431951, 3531952, GC3030L, NT3030ELS80
A cross-reference listing means this part may be a compatible replacement for these part numbers based on OEM or distributor data.
IMPORTANT INSTALLATION NOTES:
✔ Block wheels securely before removing brake chamber
✔ Depressurize the air system before disassembly or installation
✔ Confirm push rod length matches application before cutting or installing
✔ Torque mounting studs to OEM spec (typically 35–40 ft-lbs)
✔ Route service and emergency air lines to correct ports
✔ After install, check for leaks and confirm full actuation
✔ Compatible with aftermarket yoke kits (e.g., #8130004, #8130016)
✔ Ensure Stroke Alert system (if equipped) is functioning properly
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Warranty Information
