151122 OR-100 O-Ring Replacement for Big Blue Filter Pentek Housings and Compatible Systems - Buna-N Rubber Seal
151122 OR-100 O-Ring Replacement for Big Blue Filter Pentek Housings and Compatible Systems - Buna-N Rubber Seal is backordered and will ship as soon as it is back in stock.
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Description
Description
#357 Nitrile O-Ring (Buna-N NBR, 70A) - 5-1/2" ID x 5-7/8" OD x 3/16" CS
Direct replacement for the Pentek 151122 / OR-100 O-ring used in Big Blue 10" and 20" water filter housings and compatible systems. Genuine 70A Buna-N seals the sump-to-cap joint and stops the slow drip that shows up when the factory ring flattens out.
Specifications
- AS568 Dash Number: -357
- Inside Diameter: 5-1/2" nominal (5.475" / 139.07 mm actual)
- Outside Diameter: 5-7/8"
- Cross Section (Width): 3/16" (0.210" / 5.33 mm)
- Material: Nitrile rubber (Buna-N / NBR)
- Hardness: 70A durometer
- Temperature Range: -40°F to 250°F
- Color: Black | Pack of 1
Material - Why Buna-N Nitrile
Buna-N is the workhorse O-ring compound: excellent resistance to petroleum oils, fuels, hydraulic fluids, water, and silicone greases, with good abrasion and tear resistance. Not recommended for ozone/direct sunlight exposure, brake fluid, ketones, or strong acids - for those, use EPDM or Viton.
Common Applications
Big Blue 10" and 20" water filter housings (Pentek 151122 / OR-100 compatible), large tank lids and canisters.
How to Measure an O-Ring
Measure the inside diameter (hole to hole) and the cross-section thickness of your old ring, or measure the groove: groove inner diameter = O-ring ID, groove width slightly wider than the cross section. Match both numbers to the chart below - the dash number takes care of the rest.
AS568 O-Ring Size Chart - Sizes We Stock
| Dash # | Inside Dia. | Outside Dia. | Cross Section | Metric ID |
|---|---|---|---|---|
| #010 | 1/4" (0.239") | 3/8" | 1/16" (0.070") | 6.07 mm ID |
| #011 | 5/16" (0.301") | 7/16" | 1/16" (0.070") | 7.65 mm ID |
| #017 | 11/16" (0.676") | 13/16" | 1/16" (0.070") | 17.17 mm ID |
| #121 | 1-1/16" (1.046") | 1-1/4" | 3/32" (0.103") | 26.57 mm ID |
| #228 | 2-1/4" (2.234") | 2-1/2" | 1/8" (0.139") | 56.74 mm ID |
| #230 | 2-1/2" (2.484") | 2-3/4" | 1/8" (0.139") | 63.09 mm ID |
| #238 | 3-1/2" (3.484") | 3-3/4" | 1/8" (0.139") | 88.49 mm ID |
| #357 (this size) | 5-1/2" (5.475") | 5-7/8" | 3/16" (0.210") | 139.07 mm ID |
Installation Tip
Wipe the groove clean and apply a thin film of silicone grease before seating the ring - it prevents pinching and doubles seal life on anything that gets opened regularly, like filter housings.
Why Buy From Rubberfeetwarehouse
Genuine 70A Buna-N, ships fast from our South Carolina warehouse. Need a different size or larger quantity? Contact us.
Buna-N Material Guide
Buna-N Material Guide
Buna-N (Nitrile/NBR) 70A: excellent with petroleum oils, fuels, water, and hydraulic fluids. -40F to 250F. Not for ozone, brake fluid, or ketones - ask us about EPDM or Viton for those.
Delivery and Shipping
Delivery and Shipping
Usually ships within 24 hours from our South Carolina warehouse. All orders include tracking.
151122 OR-100 O-Ring Replacement for Big Blue Filter Pentek Housing...
O-Ring Specifications
| AS568 Dash Number | -357 |
|---|---|
| Inside Diameter | 5-1/2" (139.7 mm) |
| Outside Diameter | 5-7/8" (149.23 mm) |
| Cross Section / Width | 3/16" (4.76 mm) |
| Shape | Round (torus) |
| Material | Nitrile (Buna-N / NBR) |
| Hardness | 70 Shore A |
| Finish / Color | Black |
| Temperature Range | -40°F to 250°F |
| Pack Quantity | 1 |
| Fits | AS568 -357 glands: 5-1/2" ID grooves, 3/16" cross section |
| Applications | Big Blue 10" and 20" water filter housings (Pentek 151122 / OR-100 compatible), large tank lids and canisters |
AS568 nominal dimensions. Measure your groove ID and cross section to confirm fit.
O-Ring Size Calculator
Enter your O-ring's inside diameter and cross-section — get the outside diameter and recommended static groove dimensions (25% squeeze).
Measuring a worn ring? Use calipers on ID and thickness — not the stretched old ring. Compound questions: rubber compatibility chart.
Frequently Asked Questions
How do I measure an O-ring?
Measure the inside diameter and the cross-section thickness of your old ring, or measure the groove: groove ID equals O-ring ID. Match both to the AS568 chart on this page.
Is Buna-N right for my application?
Buna-N (nitrile) handles petroleum oils, fuels, water, and hydraulic fluid from -40F to 250F. It is not for ozone/direct sun, brake fluid, or ketones - ask us about EPDM or Viton for those.
Should I lubricate O-rings at install?
Yes - a thin film of silicone grease prevents pinching and roughly doubles seal life on housings that get opened regularly, like water filter sumps.
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