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I just bought a new Senco Nail gun "Washer Firing Valve" Part LB3500 but can't figure how to get it into the groove. Do I need to heat it in hot water so it will "give" a little allowing me to "stretch" it a bit or is there another trick?

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I use a heat gun similar to hair dryer and get it pretty warm. The part is pretty tough and can be forced on but better to take your time and apply heat. Good luck with your repair

Posted on Aug 29, 2010

Testimonial: "Thank you very much for the "secret". I really appreciate you taking the time to respond to my inquiry. Buz"

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  • cab001 Nov 22, 2010

    I used your hot water method and it worked for me. I boiled water in a glass in the microwave and dropped the washer in the boiling water. Got the wife to help and used two small screw drivers to walk the washer around the groove. I have a heat gun but was fearful of over heating. The boiling water keep the temperature at max. 212 degrees which was enough to make it flexible.


  • John Trevino Nov 22, 2010

    Good job and its great to have an extra pair of hands helping on repair projects. We do use hot water to install hard rubber wheels onto large rims for walk behind mowers. We use a large pot similar to those used for frying turkeys. As you feared, hot air does not heat evenly over large surface. Rubber parts can not take much abuse and will break using hot air. Have a great thanksgiving.

  • cab001 Nov 22, 2010

    Check out this Youtube video on tearing down a Senco SN 4 nail gun to replace o-rings. There is a No 1 video also.


  • John Trevino Nov 22, 2010

    The guy on the video must be a pro working on air tools. Notice the oring measuring cone in the background. He most likely does not use factory orings instead relying on universal orings sold thru bearing houses. This is a good way to save money and gives the ability to slightly oversize the oring when possible/needed. Good video thanks!



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