How to change fuel filter on NH 3930

AlbertC · 2025-08-23T11:31:01-0400

I am past due on changing the fuel filter on my NH 3930. I have never changed it because I don’t really know how and am concerned that I might screw it up and not be able to start the tractor. I am aware that if you let t diesel run out of fuel or get air in the lines it can be hard to fix.

I have attached pics of the current filter set up and a pic of the inline valve that I would assume you have to turn off before you remove the existing filter. I think this current filter set up is a modification from when the tractor was new. Can anyone walk me thru how to change this filter so that I don’t encounter any problems with it?

Thanks

TractorTech · 2025-08-23T12:47:37-0400

That is original on the emissionized engine.
Before you start, make sure you have at least a half tank of fuel. Turn the fuel off. Unscrew the black ring at the top of the filter and pull the filter down. Look to make sure there are not any seals stuck in the filter head. Push the new filter into the filter head tighten the lock ring. Turn the fuel on. Now loosen the large cap at the top of the filter head and let fuel run out until few bubbles are noted. Tighten the cap back. Set your throttle to about half speed and start the tractor.

Lineman North Florida · 2025-08-23T14:11:48-0400

Good info above, the only thing I would do different is fill the new filter full of diesel fuel before installing it.

Harry in Ky · 2025-08-23T14:55:25-0400

I don't worry about filling the filter, that's what bleeding is for. More importantly, with that style system you have no bleeder on the pump. For a novice who doesn't want to get caught with an air bubble, I would suggest you reach in and pull the wire off the shut off solenoid. After bleeding the filter I would crank the engine over at least five or six revolutions before putting the wire back on. Maybe even a little more. You stand a better chance of eliminating any air between the filter and the pump that way and minimize the possibility it will start then die two seconds later requiring bleeding the injector lines as well.