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Loctite® Vibra-Seal®

Item #: Vibra-Seal

Pre-Applied Thread Seal

Temperature Range: -65°F to +300°F; -54°C to +149°C

Reusable Up to 5 Times

Vibra Seal® Preapplied Thread Sealant is a tough, non-hardening sealant engineered to be preapplied to parts. Vibra-Seal is designed to provide an instant seal on tapered pipe threads against most fluids, fuels and lubricants but can also be used on straight threads. Vibra-Seal performs to the demanding requirements of the automotive, truck and agricultural equipment manufacturers. It provides lubricity superior to Teflon® — at a lower cost!

Long-Lok can coat entire parts (frequently done on smaller fasteners) or can apply Vibra-Seal sealant to a limited band of threads, which is typical of larger fasteners and fluid fittings.

Available in white or burnt orange colors, Vibra-Seal coatings are highly filled water based liquids that are non-toxic and non-sagging. When dried, they become a resilient, tight clinging and non-curing sealant. Vibra-Seal coated parts also resist loosening because of the prevailing torque created by the coating.

Typical Applications:

  • Rear Axle Filler Plugs
  • Bearing Adjuster Nuts
  • Overhead Fire Sprinklers
  • Pressure Gauges & Sensors
  • Cable Connectors
  • Door Closure Hardware
  • Brake Fittings
  • Compressor Pipe Plugs
  • Shower Heads
  • Pipe Fittings of all Kinds
  • Adjustment Screws
  • Screws for Plastic Assembly


Loctite® and Vibra-Seal® are Henkel AG trademarks.

Download the information sheet


In the following, "NPT" means National Pipe Threads.

Pressure Resistance - Pipe Threads

Pipe Size Burst Rating Test Pressure Test Results (Test Fluid –10 wt. Motor Oil)
½" NPT
10,400 psi (72 MPa)
10,000 psi (69 MPa) Tests discontinued with no sign of leakage
2" NPT 5,200 psi (36 MPa) 4,000 psi (28 MPa)
3" NPT 5,000 psi (35 MPa) 3,000 psi (21 MPa)


Pressure Resistance - Straight Threads

In addition to NPT joints, Vibra-Seal products can also be used to seal straight threads. Test performed on 3/8-16 straight threads, torqued up snug, exhibited excellent sealing characteristics at oil pressures up to 600 PSIG (4.14 MPa).

Steam Pressure Resistance

Tests performed on 1/2” cast iron NPT assembled with 24 lb.-in. (2.7 N•m) seating torque yielded the following results:

Steam Pressure Steam Temperature Test Results
12 psi (.014 MPa)
200°F (93°C)
Test discontinued after 1,000 hours with no sign of leakage
30 psi (.207 MPa) 250°F (121°C)


Solvent Resistance

Tests performed on 1/2” cast iron NPT at 100 PSIG (.69 MPa) hydrostatic pressure after 30 days immersion in solvents indicated.

Solvent Solvent Temperature Test Results
10 Weight Motor Oil
300°F (149°C)
No Leakage
Water 200°F (93°C)
Gasoline 77°F (25°C)
Air @ 98% Relative Humidity 100°F (38°C)
50% Glycol and Water 188°F (87°C)


Break-loose and Prevailing Torque

Vibra-Seal coated parts will resist loosening because of the prevailing torque characteristics shown below:


  • Bolts — Grade 5, 3/8”-16 x 1-1/2” zinc phosphate and oil finish
  • Nuts — Grade 2, 3/8”-16 zinc phosphate and oil finish.
Test Specimen Seating Torque Break-loose Torque Prevailing Torque – 180°
Control (No Coating)
360 lb-ins (40.7 N•m)
243 lb-ins (27.5 N•m) 0 lb-ins (0 N•m)
Vibra-Seal Coating 360 lb-ins (40.7 N•m) 175 lb-ins (19.8 N•m) 21 lb-ins (2.4 N•m)


Torque Tension

The tension in the fastener can be reasonably controlled by controlling the torque. For any given fastener the torque tension relationship can be stated as follows:


where T = Torque, lb.-in. (N•m)

D = Nominal bolt diameter, in. (m)

F = Tension or clamping force, lbs. (N)

K is a universal constant for all sizes which can be established empirically.

(You can find safe stresses for bolts in manufacturers’ fasteners specifications or tool engineers’ handbooks).


NPT joint assembly is made quicker and easier because of the lubricating ingredients in Vibra-Seal products which resist thread galling. Line-up adjustments can be made several hours after assembly without loss of sealing quality. Joints can be easily disassembled with regular tools even after years of service.


Vibra-Seal products have exhibited the ability to be reused five times on 1/2” NPT fittings which are torqued up snugly. After five uses, these fittings still maintain 300 psi (2.0 MPa) hydraulic pressure without re-coating.


Resin Coating acrylic
white or burnt orange
On-part life 4 years, minimum
Toxicity none


K Values for Vibra-Seal® Sealants*

Material K Value
Dry zinc phospate
Zinc phosphate/oil 0.11
Vibra-Seal on Dry zinc phospate 0.11
Vibra-Seal on Zinc phosphate/oil 0.09


*3/8”-16 Grade 5 bolts with Grade 2 as received nuts. Example: Vibra-Seal on 3/8”-16, Grade 5, zinc phosphate bolt:T = -.11 X 375 X 5000 = 206 lb.-in.



Vibra-Seal coatings are slightly basic and may stain or discolor some metals, especially those containing copper. However, the effect on performance of the sealant and staining of the metals is inconsequential.

Vibra-Seal coated fasteners and components are produced to order by Long-Lok. We can process your supplied parts, or we can supply complete products, including the basic fasteners or fluid fittings.

To order Vibra-Seal coated fasteners and components, or to request a quote, please call us and speak directly with one of our Sales Engineers.