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C73-744_1 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Polished
capsizes Easy Turn Fill Cap with O-Ring
1-5-8FillCap Easy Turn Fill Cap with O-Ring
2FillCap_46445667-a7e7-485b-9e89-4bade3cd7f79 Easy Turn Fill Cap with O-Ring
2-3-4FillCap Easy Turn Fill Cap with O-Ring
4-1-4FillCap Easy Turn Fill Cap with O-Ring
C73-740_1 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Black
C73-740_2 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Black
C73-740_3 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Black
C73-740_7 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Black
C73-740_6 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Black
C73-740_8 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Black
C73-741_1 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Red
C73-741_2 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Red
C73-741_3 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Red
C73-741_6 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Red
C73-741_7 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Red
C73-741_8 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Red
C73-742_1 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Blue
C73-742_2 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Blue
C73-742_3 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Blue
C73-742_6 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Blue
C73-742_7 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Blue
C73-742_8 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Blue
C73-744_1 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Polished
C73-744_2 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Polished
C73-744_3 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Polished
C73-744_6 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Polished
C73-744_7 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Polished
C73-744_8 Easy Turn Fill Cap with O-Ring 1-5 8 Inch without Lanyard Boss Polished
C73-760_1 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Black
C73-760_2 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Black
C73-760_3 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Black
C73-760_6 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Black
C73-760_7 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Black
C73-760_8 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Black
C73-761_1 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Red
C73-761_2 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Red
C73-761_3 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Red
C73-761_6 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Red
C73-761_7 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Red
C73-761_8 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Red
C73-762_1 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Blue
C73-762_2 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Blue
C73-762_3 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Blue
C73-762_6 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Blue
C73-762_7 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Blue
C73-762_8 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Blue
C73-764_1 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Polished
C73-764_2 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Polished
C73-764_3 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Polished
C73-764_6 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Polished
C73-764_7 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Polished
C73-764_8 Easy Turn Fill Cap with O-Ring 2 Inch without Lanyard Boss Polished
C73-780_1 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Black
C73-780-LB_2 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Black
C73-780-LB_3 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Black
C73-781_1 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Red
C73-781-LB_2 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Red
C73-781-LB_3 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Red
C73-782_1 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Blue
C73-782-LB_2 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Blue
C73-782-LB_3 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Blue
C73-784_1 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Polished
C73-784-LB_2 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Polished
C73-784-LB_3 Easy Turn Fill Cap with O-Ring 2-3 4 Inch with Lanyard Boss Polished
C74-780-LB_2 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Black
C74-780-LB_3 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Black
C74-780-LB_4 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Black
C74-781-LB_2 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Red
C74-781-LB_3 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Red
C74-781-LB_4 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Red
C74-782-LB_2 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Blue
C74-782-LB_3 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Blue
C74-782-LB_4 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Blue
C74-784-LB_2 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Polished
C74-784-LB_3 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Polished
C74-784-LB_4 Easy Turn Fill Cap with O-Ring 4-1 4 Inch with Lanyard Boss Polished

Easy Turn Filler Cap with O-Ring

SKU C73-744
Cap Size
Fill Cap Color
Regular price $40.99

Spend $175 to get free shipping
Crafted-in-USA Stiletto Replacement Boot and Wire Kit 2-1 4 Inch OD x 1-1 2 Inch ID: 9 Peaks: Dwarf Mod-lite Rack N Pinions

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MaleAlumFull AN Thread Weld Bung

AN Thread Weld Bung

FemaleSteelFull NPT Female Weld Bung

NPT Female Weld Bung

ORingFull Easy Turn Fill Cap Replacement O-Ring, Buna Material

Easy Turn Filler Cap Replacement O-Ring, Buna Material

1-5/8 Inch Fill Cap
1-1/4-12 Straight Thread
Cap Weight: 1.06 oz.
Without Lanyard Boss
Includes O-Ring
(Cap Replacement O-Ring is C73-749)

2 Inch Fill Cap
1-1/2-12 Straight Thread
Cap Weight: 1.62 oz.
Without Lanyard Boss
Includes O-Ring
(Cap Replacement O-Ring is C73-769)

2-3/4 Inch Fill Cap
2-1/4-10 Straight Thread
Cap Weight: 3.32 oz.
With Lanyard Boss, Accepts Lanyard Chain Kit
Includes O-Ring
(Cap Replacement O-Ring is C73-788-A)

4-1/4 Inch Fill Cap
3-3/4-8 Straight Thread
Cap Weight: 7.86 oz.
With Lanyard Boss, Accepts Lanyard Chain Kit
Includes O-Ring
(Cap Replacement O-Ring is C74-788-A)


The lightweight, non-vented cap features positive grip finger notches that are easy to get a hold of. Prime 6061-T6 billet aluminum is precision CNC machined into a lightweight, attractively designed cap; featuring quick-start coarse threads. Each screw on Cap is fitted with a Buna O-ring; positive sealing and "radially squeezed" to hold the cap secure. 

 

 

Fill Cap with O-Ring

This design uses a radial squeeze action on a Buna O-ring for a secure seal. Precision machined quick-start coarse threads make using these caps a breeze.

The large selection of Pro-werks’ mounting bungs are crafted from Steel, Aluminum or Stainless Steel and available in both weld and bolt-on styles.


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, 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

Popular Uses:

  • Custom-fabricated tanks
  • Fuel cells
  • Rear End housings
  • Valve covers
  • Overflow tanks
  • Ice boxes for intercoolers
  • Ballast tanks
  • Inspection viewing ports



Proudly Made in the USA

Be sure to check out the entire line up - Billet aluminum Easy Turn Fill Caps are a Pro-werks specialty.

You can always count on Pro-Werks to do it right!


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.

"I upgraded my fuel cell to an Easy Turn fill cap assembly. It wasn't long until all my friends did the same. Great product!"
– As shared with us at the PRI Show



Frequently Asked Questions

Q: How much do I need to tighten a fill cap?
A: It is not necessary to bottom the fill cap into the bung−just adequately seat the O-ring. The radial squeeze action on the O-ring creates a positive seal and helps prevent the cap from coming loose.

Q: What should I use to lubricate the Buna O-ring?
A: Applied periodically, a light coating of Dielectric grease has proven to work well as an O-ring lubricant.

Q: Is Buna rubber compatible with my fluid?
A: Buna is a synthetic rubber compound suitable for use with many fluids. Buna components may need to be replaced by a material compatible with the specific chemistry of some fluids.