(Confusing)  Parts book says I don't have a roll over ball.  But service manual says I do have one.  Service manual says roll over ball is on top of fuel module.  But actually  holding the fuel module in my hand, I think the roll over ball is inside near bottom near "inlet" filter.  Or at least something that looks like pic in service manual is near bottom of fuel module.  It is white and about size of ping pong ball.

 

Do roll over balls go bad?  If so I would like to replace now as fuel tank is out of truck right now. 

 

BUT!!!!  and here is part I don't understand...the fuel is being sucked by a oversize fuel line added in 2005, and the line that has roll over ball is now being used as return line to put fuel from FASS/Airdog pump. So what good does a roll over ball do anyway?   

 

I must be missing something?  Your thoughts, please. 

Edited January 22, 20178 yr by 015point9

I always thought they were at the entry point at the filler neck to stop the fuel from pouring in a rollover situation. Never laid eyes on mine. Not sure what good it would do in the fuel module.

It's in the filler neck part of tank, there is a picture here someplace. 

There is a roll over valve in the sender top (vent) and then the other roll over valve is in the filler neck of the tank. Typically the roll over valves don't go bad because you never rolled the vehicle over on its top so the openings should still be open. They are not spring loaded. So it's possible the vent tube on the sender is plugged with dirt or mud. 

 

16 hours ago, 015point9 said:

So what good does a roll over ball do anyway?   

When you roll the vehicle up side down in an accident the balls will slide to close the fuel tank off. There is one roll over valve in the top of the sender that will slide shut for the tank vent. The other roll over valve is in the filler neck that will roll shut keeping fuel from running out the tank.

 

Here is the filler neck rollover valve.

 

That ball also makes it nearly impossible to siphon gas...

56 minutes ago, Buzzinhalfdozen said:

That ball also makes it nearly impossible to siphon gas...

 

It is impossible to siphon gas... Because there is diesel in the fuel tank not gas... 

40 minutes ago, Mopar1973Man said:

 

It is impossible to siphon gas... Because there is diesel in the fuel tank not gas... 

Dang...walked right into that one didn't I. 

My first gen has a flat bed and was difficult to fill with fuel because the fill tube is almost level as if you need a block of wood to drive over with the left rear wheel and tilt the bed some.

 

After years of trouble filling the tank (had to fill very slow) I cut my ball out of there and it fills much better.

 

This gets me to wondering... up your flipped in a roll over crash isn't the ping pong ball going to float in the fuel and therefore keep the fill neck open?

My trucks been neutered I guess you could say.

No. Its weighted with lead or steel core.