all i need to know, when putting a mechanical fp guage in the truck without an isolator, does the fuel line just hose clamp on the back of the guage, or is there something else recommended?

 

All the pressure gauges I've dealt with use compression fittings.

 

is that really necessary or is it possible to just hose clamp the hose to the threads, will the seal be just as good.

 

No, I would use the nylon tubing and the compression fitting.

 

Do it right the first time, and you won't have to do it twice.
Mechanical fittings only , IE: Compression fitting or -AN fitting.
No Mickey Mouse connections on a fuel line, especially inside the cab.

 

ok, that's what i figured, but now another question, why the nylon tubing, can i use rubber tubing?

 

and another, can ya'll explain how the banjo bolt works?

 

I like threaded fittings. I use 60" of grease gun lines and fittings sealed with permatex non-hardening thread sealer. My cheapo setup is in my picture gallery.

 

Use the nylon, it's compression, you don't have much of a choice (ulness you want to fight copper) then "sheath" it with a 6' piece of 1/8" or 3/16" fuel hose from NAPA. This way it is protected from abrasion or kinks. We are only taking 15 psi here.
I used the 1/8", I had to soap it up a little to get it to slide though, but this way you don't have a big clunky hose behind your gauge.

DON'T over tighten!

 

The banjo bolt and fitting is a compression fitting with 2 sealing washers. The bolt is drilled up through the center of the bolt to the shoulder then is drilled into the side of the bolt intersecting the center drilled hole. The fitting has a feeder line and a cavity that surrounds the banjo bolt. One sealing washer seals the bolt to the fitting and the other seals the fitting to the device they're connected to.
Fuel can travel through the fitting feeder line to the fitting cavity, enter the banjo bolt through the side hole then out through the center hole into the device receiving the fuel. It can flow in reverse to the description too.
Clear as mud huh?

 

Like PJ said, your choices are nylon and copper. Nylon is better than copper in automotive applications because it does not work harden and become brittle from vibration.

 

If you don't use some kind of isolator, the pulses will probably wreck the gauge in a very short time. You can use a brass needle valve for an isolator.

 

Actually the Needle Valve works as a snubber, not an isolator.

 

Got that backwards. A needle valve will not "isolate" anything (unless you keep it shut?)