Hydraulic Seal (61821)

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What it's for:
  • Hydraulics
What it does:
  • Cleans
  • Lubricates
  • Stops Leaks
  • Repairs
  • Preventative Maintenance
  • Keeps hydraulic seals soft and pliable
  • Reduces friction and wear in hydraulic systems
  • Cleans and prevents harmful formation of sludge and varnish
  • Helps hydraulic systems run cooler and last longer
  • Mixes with all factory approved hydraulic fluids and synthetics
  • Will Rislone Hydraulic Seal work with all regular types of hydraulic fluids?

    Yes, Rislone Hydraulic Stop Leak is compatible with all petroleum based, mineral oil, and synthetic fluids. Do not use with water-glycol or phosphate ester flame retardant hydraulic fluids. Do not use in brake fluid systems.

  • How does Hydraulic Seal work?

    After time, hydraulic seals and o-rings tend to dry out and shrink. Rislone revitalizes these seals and o-rings and makes them soft and pliable again.

  • How much Hydraulic Seal do I install?

    61821 is designed to be installed with one ounce per quart of fluid. When using the 61812 (Hydraulic Jack Oil with Stop Leak) top off fluid levels as needed.

  • How much Hydraulic Seal does a package treat?

    61821 (3.8L) and bulk are designed to be installed with 30mL per liter of fluid. When using the 61812 (Hydraulic Jack Oil with Stop Leak) top off fluid levels as needed.

  • If first application does not completely stop leak, may I add another dosage?

    Yes, you can install a second application for hard to stop leaks. If your leak still persists after a second application, then mechanical attention is needed, and replacement of seals may be required.

  • Can Hydraulic Seal be used for preventative maintenance to help prevent leaks?

    Yes, this is a great product to use in older systems to keep them working properly not only to prevent leaks, but keep the system lubricated and protected. The recommended preventative maintenance dose is 15mL per liter of fluid capacity.

  • How long does it take to start working?

    Rislone Hydraulic Seal starts working the minute you install and start using equipment. Most leaks are sealed within a few hours of application and usage. Some leaks can take longer, up to a few days. Old accumulation of fluid on outside of system may drip for a few days after leak has stopped.

  • My hydraulic system uses motor oil, can I still use Hydraulic Seal?

    Yes, Hydraulic Seal will mix and work perfectly in a hydraulic system using motor oil.

  • Will Hydraulic Seal change the fluid viscosity?

    No, we have designed the formulation using a multi-viscosity hydraulic fluid as a carrier which when used at the recommended dosage will not take ISO 22, ISO 32, ISO 46, ISO 68 or ISO 100 out of grade specification.

  • Will Hydraulic Seal harm painted surfaces?

    No, this product will not affect painted surfaces any differently than straight hydraulic fluid.

  • Will Hydraulic Seal harm hoses?

    No, this will not harm or affect hoses in any way.

  • What is the difference between hydraulic fluid and hydraulic oil?

    Nothing, they are the same thing, just a terminology difference.

Rislone Hydraulic Seal is specially designed to repair hydraulic fluid leaks, reduce friction/wear and renew seals and O-rings in hydraulic systems. This product is engineered to be professional-grade and is safe to use for consumer applications as well as commercial use cases. Rislone Hydraulic Seal works with all petroleum and synthetic fluids, pump seals, control valve seals, actuators, rams, cylinders, O-ring boss fittings and hydrostatic transmissions.

In addition, Rislone Hydraulic Seal:

  • Keeps hydraulic seals soft and pliable
  • Reduces friction and wear in hydraulic systems
  • Cleans and prevents formation of sludge and varnish
  • Helps hydraulic systems run cool and last longer
  • Mixes with all factory-approved hydraulic fluids and synthetics

All of our leak repair solutions are the result of over 70 years of extensive research. Since our first year in business, we’ve been synonymous with stopping leaks in consumer, commercial, OEM applications. When you choose Rislone, you can depend on proven performance at a reasonable price, backed by a company that knows leaks better than anyone else in the world.


You have a job to do, or jobs to oversee, or heavy duty applications that cannot suffer downtime. We get it. With Rislone leak repair products, you’ll find solutions for not only hydraulic systems, but also cooling systems, head gaskets, engine oil, power steering, and transmissions. Each Rislone solution is easy to use, which means you need no advanced skills or expertise to install it.

Made in the U.S.A., just an hour northwest of Detroit, Rislone formulas are developed and manufactured by a crew that’s dedicated to making leaks a thing of the past. We’re always looking for the best methods to keep pace with automotive and hydraulic technologies and innovations. When you want a pro-grade hydraulic leak seal you can rely on, choose Rislone, the most trusted name in chemical repairs.

Part Number: 61821
Dosage: One bottle treats 121 liters
Size: 3.8 L

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