Collection: Auto - Fitting Cap

Protect your vehicle’s sensitive fuel, oil, and brake systems with our selection of Auto Fitting Cap components. At DIY Customs, we provide high-quality aluminum AN fitting caps, durable brass flare plugs, precision-engineered thread protectors, and heavy-duty dust caps designed for a perfect fit. Whether you are temporarily sealing off lines during an engine swap, protecting exposed threads on a transmission cooler, or capping unused ports on a custom fuel rail, our professional-grade hardware offers the leak-proof seal and corrosion resistance you need at unbeatable prices. From specialized JIC caps to metric thread plugs, we carry the essential gear to keep your plumbing systems uncontaminated. Don't see the specific fitting size or specialized high-pressure cap for your build? Hit the live chat or call 412-882-8346—we can special order and drop-ship exactly what you are looking for directly to your doorstep!