Spring and ball

[DIESEL/VETTE]

Going to rebuild my filter head with primer, what is the purpose of the spring & ball, i read that people that change there filters to the nick tane system, remove the ball and spring. If you use the gm filter should you leave the spring and ball in place? Thank you

[Kennedy]

My take on that ball and spring is that it is there to prevent backflow/drainback of the lines when the filter is removed. The mounting location of the filter housing really does not allow drainback anyhow so there is no reason that it cannot be removed and left out.

I would never run a nicktane, but the reason that they remove is because the adapter lacks the "poker" in the middle that the OE filter has to displace the ball. With the adapter it would just be wide open anyhow when the filter was removed so no reason to keep it.

[More Power]

My take on that ball and spring is that it is there to prevent backflow/drainback of the lines when the filter is removed.

Would this apply if an owner didn't loosen the truck's fuel tank cap before removing the old fuel filter, and some amount of vacuum existed in the tank?

[Kennedy]

The ball and spring would only affect the system from the filter head center post to the CP3. I probably should have clarified in my earlier post, but the filter head is at a high point and the hoses exit at a downward angle so minima drip will occur with the ball and spring removed. This drip back will occur about immediately when you break the seal if not sooner. If the truck does not have a lift pump the fuel will just go back to the filter as you will undoubtedly have a half full filter anyhow.

The fuel filter housing has a pair of butterfly check valves that allow the hand pump to do it's job. When the pump is depressed the one at the inlet needs to be closed so that the pump can build pressure otherwise it would just push back to the tank. This should prevent excess drainback to the tank when the filter is removed as well.

Side note: There is no real measureable vacuum in the tank with a properly functioning cap. It will most always be pressure if anything. Otherwise we'd have the tanks suck air when opened cold. To test the cap function all you have to do is put the cap in your mouth and see for yourself. I know it tastes bad, but wipe/wash as best you can. Inhale and it yields VERY easily a somewhat metered amount of air. Exhale and it locks up resisting flow.

[DmaxMaverick]

Would this apply if an owner didn't loosen the truck's fuel tank cap before removing the old fuel filter, and some amount of vacuum existed in the tank?

I've not read the operational description of the valve (or filter assy, for that matter), but it appears the spring/ball is on the clean side of the plumbing. Meaning, it's there to prevent drain-back from the pump, intended to prevent loss of prime.

Also, I've noticed it makes little difference, if any, when the vacuum is relieved via the cap or not. Unless you are really fast at getting the filter sealed up, gravity will beat you to it, anyway. Anymore, I use a modified filler cap and apply low pressure air after a change (on trucks w/o a lift pump). A couple/few pumps and done. It will also immediately show if the O-ring isn't properly engaged or sealed.

[DIESEL/VETTE]

Thank you both for your reply, i left the ball and spring in place. Removed the nicktane adaptor, and am using the new racor pff-50216 filter along with john's single lift pump and all my start and die problems have disappeared. I still use the cat ir-750 after the lift pump and before the racor filter. After 1500 miles my truck run's like it did when new. Thank you