Racor fuel filter filter guage

[Grumpymx]

I was wondering if anyone has any experience using a pressure gauge to monitor their Racor fuel filter and could save me some trial and error.

I currently have a vacuum gauge mounted on the top of my Racor 500 to monitor the filter but wish to pressurize the system by moving the Steward Warner electric pump from between the Racor and the engine filter to back by the tank to make bleeding easier and to ID leaks .

Does anyone know
If I put a 1-10 PSI fuel pressure gauge after the Racor will the pressure drop a little bit when the filter needs changing?

Or should I put the pressure gauge before the Racor and look for a increase in pressure as the filter clogs?

The pump produces 6-7 psi, but due to a pressure release bypass to the return line the system runs at about 3 psi.

Engine is a Perkins 4108 Diesel

Thank you in advance for any assistance you may be able to offer

[sailingdog]

The idea of using a vacuum gauge is that the vacuum level for the fuel line will rise as the filter gets clogged up. Putting the fuel pump upstream of the Racor filters basically kills most of the usefulness of a vacuum gauge on the Racor filter, since the Racor is now under pressure, rather than vacuum.

[Grumpymx]

I understand that the vacuum gauge will no longer work and I was going to just replace it with the original "T" handle for the Racor.

Would a fuel pressure gauge in one of the configurations above accomplish the same thing? By showing a pressure increase or decrease as the filter was getting near the end of it's usefulness ?

Or am I barking up the wrong tree ?

[sailingdog]

A pressure gauge really doesn't help much either...

[Grumpymx]

Ok thanks, I'll scrap the idea.

[sailingdog]

I think you'd be better off leaving the fuel pump downstream of the Racor filters, and leaving the vacuum gauge as a warning tool for filter quality. If the fuel pump is after the Racors but before the rest of the fuel system, it should allow you to bleed the fuel system pretty thoroughly... a small rubber fuel bulb upstream of the Racor filters will allow you to bleed any air from the Racors themselves pretty reliably.