Dexter Fortress Threaded Cap - 10,000 HD - 15,000 lbs. K21-301-00

Keep your heavy-duty trailer rolling with confidence using the Dexter Fortress Threaded Aluminum Oil Cap K21-301-00. Designed for compatible 10,000–15,000 lb Dexter HD oil bath axles, this genuine replacement oil cap provides a secure, leak-resistant seal to help protect your trailer's hub and wheel bearings from contamination and lubricant loss.

A worn, damaged, or leaking oil cap can allow oil to escape and dirt, water, or road debris to enter the hub—leading to premature bearing wear, costly repairs, and unnecessary downtime. Replacing your oil cap is an easy and affordable way to maintain proper hub lubrication, extend bearing life, and keep your trailer performing safely on every trip.

Features & Benefits

• Genuine Dexter replacement part for compatible Fortress oil bath hub systems
• Fits select 10,000–15,000 lb HD Dexter trailer axles
• Durable threaded aluminum construction for a secure, dependable fit
• Helps maintain proper oil levels inside the hub
• Prevents dirt, moisture, and road contaminants from reaching wheel bearings
• Ideal for routine trailer maintenance or replacing damaged oil caps
• OEM quality for reliable fit, performance, and long service life

Ideal Applications

Perfect for heavy-duty equipment trailers, gooseneck trailers, flatbed trailers, lowboy trailers, livestock trailers, commercial trailers, and other trailers equipped with compatible Dexter Fortress oil bath hubs.

Don't let a small oil cap become a big repair bill. Replacing a damaged or leaking cap helps keep your oil bath hubs properly sealed, protects your wheel bearings, and reduces the risk of costly downtime. Trust genuine Dexter parts to keep your trailer ready for every mile and every haul.