Stemco 300-4009 Oil Hub Cap 6-Bolt 5.5" Circle for Dexter 22.5K–27.5K Axles | Replaces 021-038-02

✅ STEMCO 300-4009 Oil Hub Cap – 6-Bolt, 5.5" Bolt Circle w/ Gasket & Plug

Fits: Dexter 22,500–27,500 lb. heavy-duty air brake axles
Includes: Pre-installed red plug (359-5990) and gasket (330-3009)
Stemco Part Number: 300-4009
Dexter Cross-Ref: 021-038-02
Non Bulk Equivalent: 340-4009

This is a genuine STEMCO aluminum hub cap engineered for long-lasting durability and trusted performance. Built with a 6-bolt pattern and cast aluminum housing, it’s made to withstand high temperatures and resist warping in severe-duty air brake applications.

🔧 Key Features:

• Fits Dexter 22.5K–27.5K air brake axles

• 6-bolt mounting, 5.5" bolt circle (5/16" bolts)

• Includes gasket (330-3009) and vented red plug (359-5990)

• Made from cast aluminum for superior strength and heat dissipation

• Overall depth: 2-11/16" | Inside depth: 1-15/16"

• Flange ID/OD: 4-3/8" inner, 6-1/4" outer

• Suitable for oil, semi-fluid grease, or hard-pack grease

• Red plug design allows controlled venting

🔩 Common Applications:

• Dexter heavy-duty trailer axles with air brakes

• 22,500 lb. and 27,500 lb. hub systems

• Suitable for fleets using oil bath or semi-fluid lubrication

📦 What’s Included:

• One STEMCO 300-4009 aluminum hub cap

• Installed red plug (359-5990)

• Gasket (330-3009)

🔁 Replacement & Related Parts:

• Stemco 359-5990 Red Plug for Oil Caps

• Stemco 330-3009 Gasket for Oil Caps

• Bulk version of Stemco 340-4009 (no retail packaging)

🛠️ Engineered to Last:

STEMCO has been the industry standard in hub caps for over 60 years. This cap uses cast aluminum to reduce heat and resist warping—essential for high-load, high-heat environments. The trademark red plug allows venting and pressure equalization, extending hub life and reducing service needs.

Designed for heavy-duty commercial fleets looking for premium, long-life performance.