svg Image How to repair a Spray Gun - MTM Hydro Parts Powered by Veloci | MTM Hydro Parts - Powered by Veloci Performance Products - MTM Hydro

How to repair a Spray Gun - Inside a Spray Gun

Posted by on

MTM Hydro spray guns are among the best in the industry. The SG line being the most popular. Because of their ergonomic and easy pull design...not to mention their durability. While extremely durable, parts wear can happen, especially in high volume use cases such as construction, industrial, detailing, and restaurant cleaning industries. For this reason, Veloci Performance offers repair kits for all MTM Hydro spray guns.

In this blog, we’re going to walk you through how to service the SG28, SG35, and SG35 Acid Spray Guns. Follow these steps to get your spray gun back up and running!


What you’ll need:

T15 Torq bit
2 ½" mm allen wrench
¾” socket
Standard screwdriver


 spray gun mtm hydro repair kit


  • Remove all the 6 torq screws that hold the plastic body of the spray gun together. These can be found around the edges of the spray gun. 
  • Once opened up, remove the trigger plug and set aside
  • Now, remove the whole interior body of the gun from the plastic casing. Set the plastic body to the side.
  • Take your allen wrench and remove the trigger from the spray gun piping. This pin will only come out in one direction so make sure to try both ways.
  • Identify the front and back plugs of the spray gun. The front plug is smaller and faces the direction that the spray gun would spray. The back plug is larger and sits at the top of your spray gun handle.
  • Use the allen wrench to remove the back plug from the spray gun piping. You may need a vice to get this part loose
  • Remove all contents from the back plug chamber.  You should end up with a spring and ceramic ball.
  • Next, insert your allen wrench into the front plug to push out the pin located inside the back plug chamber.
  • Use any tool necessary to remove the “seat” – where the ball sits inside of the back plug chamber.
  • It’s time to remove the front plug! Unscrew the front plug from the spray gun piping with a standard screwdriver.
  • Remove the contents of the front plug chamber. This should be a gasket and an o ring.

Now it’s time to replace parts and reassemble.



Use one of the Veloci Spray Gun repairs kits available on our website or sold with our Dealer Network.

  • Starting with your front plug, place your new o ring and gasket back in place where the old pieces were sitting
  • Screw on the front plug and secure tightly
  • Flip the spray gun over and start replacing your parts with the back chamber
  • Replace the “seat” first. Make sure to place the flat side down and the shoulder side up.
  • Replace the pin through the middle of the seat. You may need to push the pin up through the front plug.
  • Insert the new ball into the back plug chamber so that it sits on top of the seat
  • Next, take your back plug and place your new spring into its shuttle. Together take that combination and place into the back plug chamber over the ball and pin.
  • Use your socket to tighten the back plug to the spray gun piping. Make sure this is tight, as it will be under intense pressure when the spray gun is engaged.
  • Reinstall the trigger to the spray gun piping by using the pin. Remember it will only fit one direction.
  • Place your spray gun piping back into the plastic spray gun body.
  • Next place the trigger guard into its notch.
  • Bring the plastic spray gun body parts together around the piping and tighten your Torq screws.

Congratulations! You have replaced your spray gun internals successfully!


If you are struggling with this process, call or email our Customer Service team with questions.


Blog MTM Blog spray gun

← Older Post Newer Post →

// back order