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Aluminum Bolt-On Bung Cap Assembly

Choose your size. Choose your color.

Bolt-On Cap & Bung Assembly
Cap Size	Black	Red	Blue	Silver	Polished
1-5/8" Cap	C73-735-B	C73-736-B	C73-737-B	C73-738-B	C73-739-B
2" Cap	C73-755-B	C73-756-B	C73-757-B	C73-758-B	C73-759-B
2-3/4" Cap	C73-775-B	C73-776-B	C73-777-B	C73-778-B	C73-779-B

Image	Part Number	Description
	C73-735-B	1-5/8 in. BLACK FILL CAP WITH ALUMINUM BOLT-ON BUNG 1-1/4-12 Straight Thread 4 on 2 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-749 & Bung Replacement O-Ring is C73-748)
	C73-736-B	1-5/8 in. RED FILL CAP WITH ALUMINUM BOLT-ON BUNG 1-1/4-12 Straight Thread 4 on 2 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-749 & Bung Replacement O-Ring is C73-748)
	C73-737-B	1-5/8 in. BLUE FILL CAP WITH ALUMINUM BOLT-ON BUNG 1-1/4-12 Straight Thread 4 on 2 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-749 & Bung Replacement O-Ring is C73-748)
	C73-738-B	1-5/8 in. SILVER FILL CAP WITH ALUM BOLT-ON BUNG 1-1/4-12 Straight Thread 4 on 2 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-749 & Bung Replacement O-Ring is C73-748)
	C73-739-B	1-5/8 in. POLISHED FILL CAP WITH ALUMINUM BOLT-ON BUNG 1-1/4-12 Straight Thread 4 on 2 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-749 & Bung Replacement O-Ring is C73-748)
	C73-755-B	2 in. BLACK FILL CAP WITH ALUMINUM BOLT-ON BUNG 1-1/2-12 Straight Thread 4 on 2.25 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-769 & Bung Replacement O-Ring is C73-768)
	C73-756-B	2 in. RED FILL CAP WITH ALUMINUM BOLT-ON BUNG 1-1/2-12 Straight Thread 4 on 2.25 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-769 & Bung Replacement O-Ring is C73-768)
	C73-757-B	2 in. BLUE FILL CAP WITH ALUMINUM BOLT-ON BUNG 1-1/2-12 Straight Thread 4 on 2.25 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-769 & Bung Replacement O-Ring is C73-768)
	C73-758-B	2 in. SILVER FILL CAP WITH ALUMINUM BOLT-ON BUNG 1-1/2-12 Straight Thread 4 on 2.25 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-769 & Bung Replacement O-Ring is C73-768)
	C73-759-B	2 in. POLISHED FILL CAP WITH ALUMINUM BOLT-ON BUNG 1-1/2-12 Straight Thread 4 on 2.25 in. Dia. Bolt Circle 9/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-769 & Bung Replacement O-Ring is C73-768)
	C73-775-B	2-3/4 in. BLACK FILL CAP WITH ALUMINUM BOLT-ON BUNG 2-1/4-10 Straight Thread 5 on 3.125 in. Dia. Bolt Circle 11/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-788-A & Bung Replacement O-Ring is C73-789)
	C73-776-B	2-3/4 in. RED FILL CAP WITH ALUMINUM BOLT-ON BUNG 2-1/4-10 Straight Thread 5 on 3.125 in. Dia. Bolt Circle 11/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-788-A & Bung Replacement O-Ring is C73-789)
	C73-777-B	2-3/4 in. BLUE FILL CAP WITH ALUMINUM BOLT-ON BUNG 2-1/4-10 Straight Thread 5 on 3.125 in. Dia. Bolt Circle 11/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-788-A & Bung Replacement O-Ring is C73-789)
	C73-778-B	2-3/4 in. SILVER FILL CAP WITH ALUMINUM BOLT-ON BUNG 2-1/4-10 Straight Thread 5 on 3.125 in. Dia. Bolt Circle 11/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-788-A & Bung Replacement O-Ring is C73-789)
	C73-779-B	2-3/4 in. POLISHED FILL CAP WITH ALUMINUM BOLT-ON BUNG 2-1/4-10 Straight Thread 5 on 3.125 in. Dia. Bolt Circle 11/16 in. Bung Height Includes mounting hardware and Buna O-rings. Made in the USA (Cap Replacement O-Ring is C73-788-A & Bung Replacement O-Ring is C73-789)

Bolt-On Bung and Cap Assembly

The Pro-Werks Bolt-on fill assemblies require no welding; this produces a very clean finished installation every time. The base of the bung is machined to accept the provided Buna O-ring for a positive seal, mounting hardware is included.

Leak proof.

There are many very useful applications; ideal for composites when welding isn't an option and thin gauge materials that are too difficult to weld, or any installation that already has a sensitive protective finish applied. These are a favorite of engine builders for valve covers.

Fitted with the popular non vented Easy Turn Fill Cap, featuring positive grip finger notches that are easy to get a hold of. The 6061-T6 billet aluminum cap is CNC machined into a lightweight, attractive design with quick-starting coarse threads and positive sealing "radially squeezed" Buna O-Ring – which also holds the cap secure.

Great caps. Great colors.

To compliment the color coordination of your project, the caps are finished off in Pro-Werks Brilliance anodized colors in your choice of black, red, blue, silver, or beautifully Micro-polished aluminum – the finishes are impeccable.

The right size matters.

Easy Turn Fill Caps come in many sizes and are packaged as complete assemblies with your choice of one of the many versatile mounting options, or each component is also available separately.

Be sure to check out the entire line up - Billet aluminum Easy Turn Fill Caps are a Pro-Werks specialty. Watch the Video below to learn more !

Proudly Made in the USA

Customer Comments:

"I use your bolt on caps and bungs on my carbon fiber Cummins common rail valve covers. Love the quality. Thank you."
– Randy Davis, Owner of OldSkoolFab, Inc.

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Finish Your Tank

We also offer a full line of weld-in plumbing bungs to complete your tank project.

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