Description
RA4020 – FRUEHAUF HUB CAP
PART NUMBER(S):
Fleet Products: RA4020 (New) | OE: Stemco 340-4975, Pro Trucking M1052, 4975, 340-4975, 180.10618, 7538-900, 7538-900 Automann 180.10618
DESCRIPTION:
Model: Fruehauf Screw-On Hub Cap
Vehicles: Fruehauf Pro-Par trailers, GMC, Mack, Wabash, Great Dane, and other heavy-duty trailers with threaded hub assemblies with HM518445 bearings and screw-on hub caps
• Mounting Style: Spin-On (Threaded)
• Screw-On Thread Diameter: 6.250"
• Overall Height: 2.313" (2-5/16")
• Inside Depth: 1-9/16"
• Flange Outer Diameter: 6-7/8"
• Flange Inner Diameter: 5-3/4"
• Material: Clear Lexan
• Side Fill Plug: No (standard screw-in design)
• Gasket: O-ring seal type (RA4021)
• Application Type: Oil or grease-filled wheel hubs
• Function: Retains lubricant, prevents contaminants, supports hubodometer fitment (Stemco 640-0003 variant)
Applications:
Designed for Fruehauf Pro-Par trailers and other heavy-duty wheel-end systems using threaded hub caps. Provides OEM-grade sealing to protect bearings, retain oil or grease, and allow easy maintenance. Compatible with hubodometer-style caps when specified.
CROSS-REFERENCE(S):
RA4020, 340-4975, 3404975, 340-4977, 3404977, 340975, 340-975, 640-0003, 6400003, 742-6400003, M1052, M-1052, 130-M1052, 110670, 11-0670, 1282, 1283, 1382, 203-456, 203456, 8-295, E-04075, E04075, E-04975, E04975, H075, ACC7538-900, GL-4913, L-885, L885, 7843-3404975, MER04975, R004075, WA14-5000, WA145000, WA340-4975, WA3404975, THC-9918, 9013, GT-4020, GT4020, GT-4020B, GT4020B, MST404975, IMT340-4975, STE340-4975, ST340-4975, STM3404975, STM 340 4975, STM3524009, SM-340-4975, PL-340-4975, RB-340-4975, SAP-HC124975, S-B359, SIR9013, HC04075, HC4975, HC4975B, DGP, U51L885, NOS1282, ZCP3404975, CRI1283, 3918032, 401911P, 64075P, DG-P, 23001, 1282CHR, 340975BK, 180.10618, 18003005, 11001005, MU180385, PB180108, ROS11001005, G543, M-1052, M1052, 110670, 11-0670, E-04075, E04075, ACC7538-900, GL-4913, L-885, 7843-3404975, WA14-5000, WA340-4975, THC-9918, 9013, WA3404975, WA145000, L885, GT-4020B, GT4020B, E-4075, 1284, CR1284, 3404975, L885
A cross-reference listing means this part is a suitable replacement for the part numbers listed. Always confirm thread size and hub type before installation.
IMPORTANT INSTALLATION NOTES:
✔ Designed for spin-on (threaded) installation — verify 6.25" thread match.
✔ Ensure O-ring gasket (330-3077) is properly installed before tightening.
✔ Tighten by hand until seated, then torque carefully to OE spec to avoid cross-threading.
✔ Do not overtighten; overtightening can crack Lexan versions.
✔ Always inspect sealing surfaces for debris or wear before installation.
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Warranty Information
