April 1, 2013

How to install a pressure washer O-ring kit

By Lyle Weischwill
How to install a pressure washer O-ring kit

Over time, the O-rings that seal the fittings on a pressure washer pump wear down, allowing leaks at the fittings. This step-by-step pressure washer repair guide explains how to replace the O-rings in a leaking pressure washer pump, using a manufacturer-approved replacement O-ring kit.

Use these steps to install the O-ring kit in Craftsman, Generac, Briggs & Stratton, Snapper, Husqvarna and Troybilt pressure washers.

Quick links
Tools required
Metric wrench set
Silicone lubricant
Thread-locking adhesive
Torque wrench (optional)
Work gloves
Repair difficulty
Time required
45 minutes or less
Repair difficulty
Time required
45 minutes or less

Instructions

  1. 01.

    Disconnect the spark plug

    Disconnect the spark plug wire from the spark plug.

  2. 02.

    Sort the O-rings

    Sort the O-rings in the kit by size.

    Tip: You may not need all of the O-rings included in the kit.
  3. 03.

    Remove the high-pressure outlet fitting

    Using the proper size wrench, turn the high-pressure outlet fitting counter-clockwise to remove it from the pump.

    Remove the high-pressure outlet fitting.

    Remove the high-pressure outlet fitting.

  4. 04.

    Install the O-ring on the outlet fitting

    Pull the old O-ring off of the high-pressure outlet fitting.

    Clean any residue from the old O-ring off of the threads of the high-pressure outlet fitting.

    Insert the new O-ring on the high-pressure outlet fitting.

    Lubricate the new O-ring with a small amount of silicone lubricant.

    Remove the O-ring.

    Remove the O-ring.

    Install the new O-ring.

    Install the new O-ring.

  5. 05.

    Reinstall the high-pressure outlet fitting

    Apply a small amount of thread-locking adhesive to the threads of the high-pressure outlet fitting.

    Reinstall the high-pressure outlet fitting onto the pump and thread it into place.

    Tighten the high-pressure outlet fitting securely using a wrench.

    Reinstall the high-pressure outlet fitting.

    Reinstall the high-pressure outlet fitting.

  6. 06.

    Remove the unloader valve

    Using the proper size wrench, turn the unloader valve counter-clockwise to remove it from the pump.

    Loosen the unloader valve.

    Loosen the unloader valve.

    Remove the unloader valve.

    Remove the unloader valve.

  7. 07.

    Install the new O-ring on the unloader valve

    Pull the old O-rings off of the unloader valve.

    Clean any residue from the old O-rings off of the unloader valve.

    Insert the new O-rings on the unloader valve.

    Lubricate the new O-rings with a small amount of silicone lubricant.

  8. 08.

    Reinstall the unloader valve

    Thread the unloader valve into the pump and tighten it with the wrench.

    Tip: If you have a torque wrench, tighten the unloader valve 10-12 ft.-lbs.
    Reinstall the unloader valve.

    Reinstall the unloader valve.

  9. 09.

    Remove the chemical injection valve

    If there’s detergent in the detergent reservoir, clamp the chemical injection hose near the chemical injection valve.

    Pull the chemical injection hose off of the valve.

    Using the proper size wrench, turn the chemical injection valve counter-clockwise to remove it from the pump.

    Clamp off the chemical injection hose.

    Clamp off the chemical injection hose.

    Pull the chemical injection hose off of the valve.

    Pull the chemical injection hose off of the valve.

    Remove the chemical injection valve.

    Remove the chemical injection valve.

  10. 10.

    Install the new O-ring on the chemical injection valve

    Pull the old O-ring off of the chemical injection valve. 

    Clean any residue from the old O-ring off of the chemical injection valve.

    Insert the new O-ring on the chemical injection valve.

    Lubricate the new O-ring with a small amount of silicone lubricant.

  11. 11.

    Reinstall the chemical injection valve

    Thread the new chemical injection valve onto the pump and tighten. Reconnect the chemical injection hose. 

    Release the clamp from the chemical injection hose, if used.

    Tip: If you have a torque wrench, tighten the chemical injection kit 10-12 ft.-lbs.
    Reinstall the chemical injection valve.

    Reinstall the chemical injection valve.

    Reconnect the chemical injection hose.

    Reconnect the chemical injection hose.

  12. 12.

    Remove the check valve caps

    Use the proper size wrench to remove the check valve caps from the side of the pump. Turn the check valve caps counter-clockwise to remove.

    Remove the manifold check valve caps.

    Remove the manifold check valve caps.

  13. 13.

    Install the O-rings on the check valve caps

    Pull the old O-rings off of the check valve caps.

    Clean any residue from the old O-rings off of the check valve caps.

    Insert the new O-rings on the check valve caps.

    Lubricate the new O-rings with a small amount of silicone lubricant.

  14. 14.

    Reinstall the check valve caps

    Place a small amount of thread locking adhesive on the check valve cap threads.  

    Reinstall the check valve caps and tighten them securely. 

    Tip: If you have a torque wrench, tighten the valve caps 18-20 ft.-lbs.
    Reinstall the manifold check valve caps.

    Reinstall the manifold check valve caps.

  15. 15.

    Reconnect the spark plug wire

    Reconnect the spark plug wire to the engine and test the operation and check for any leaks.

  16. 16.

    Test the pressure washer

    Start the pressure washer and check for leaks.

Warning: Undertaking repairs to appliances can be hazardous. Use the proper tools and safety equipment noted in the guide and follow all instructions. Do not proceed until you are confident that you understand all of the steps and are capable of completing the repair. Some repairs should only be performed by a qualified technician.

Symptoms for gas pressure washers

Choose a symptom to see related pressure washer repairs.

Things to do: tune up the engine, inject pump saver into the water pump when storing the pressure washer for the winter
Main causes: broken recoil spring, damaged recoil starter
Main causes: overfilling engine with oil, improper fuel/air mixture, choke system problems, dirty carburetor, engine needs tune up
Main causes: dirty air filter, stale fuel, clogged or dirty carburetor, bad unloader valve
Main causes: pump running for more than 5 minutes when the spray wand isn't being used, faulty pressure relief valve, bad unloader valve
Main causes: damaged recoil starter, oil inside cylinder, locked up engine piston
Main causes: using a high-pressure spray tip when applying detergent, clogged siphon tube, chemical injection system failure
Main causes: stale fuel, gummed up carburetor, engine needs tune up, throttle and choke controls need adjustment, bad recoil starter
Main causes: insufficient water supply, clogged water inlet screen, clogged pressure hose, faulty pump check valves, stuck unloader valve

Repair guides for gas pressure washers

These step-by-step repair guides will help you safely fix what’s broken on your pressure washer.

April 1, 2013
By Lyle Weischwill
How to replace a pressure washer pump

The pump can be damaged by air in the inlet water supply or by chemicals that remain in the pump body after using the chemical injection system. Follow these steps to replace a damaged pump.

Repair difficulty
Time required
 30 minutes or less
April 1, 2013
By Lyle Weischwill
How to install a pressure washer O-ring kit

O-rings seal fittings on the pressure washer pump. Damaged seals allow water to leak from the pump. Follow these steps to replace the O-rings in a leaking pressure washer pump.

Repair difficulty
Time required
 45 minutes or less
How to install a pressure washer chemical injection kit

The chemical injection valve draws detergent into the pump. If it’s not drawing detergent, use a repair kit to replace the chemical injection valve.

Repair difficulty
Time required
 15 minutes or less

Articles and videos for gas pressure washers

Use the advice and tips in these articles and videos to get the most out of your pressure washer.

January 1, 2016

Choosing the correct spray tip for a pressure washer

By Sears PartsDirect staff

Spray tips vary in pressure and angle of spray. This guide matches the spray tip to the cleaning job.

November 1, 2015

7 steps for winterizing and storing a pressure washer

By Sears PartsDirect staff

Follow this advice to winterize your pressure washer.

April 1, 2015

Pressure washer common questions

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