While we are discussing Racors

[jpendoley]

What's with the SAE fittings (inlet and outlet) and the O rings? I just installed a new Racor 500 FG-2 and its leaking slowly drip drip drip. How tight should the fittings be? I'm concerned that I might distort or damage the o ring-but the fittings still can be turned now without a wrench. Should I use pipe sealant?

[a64pilot]

The Racor fittings are proprietary, I don’t know what they are exactly, but only the “proper” fitting will work.
Where did you get your fittings?

If you have the proper fittings they should be tightened just like a normal fitting, do not use any kind of sealant, maybe lube the o-ring.

[scherzoja]

The fittings and o-rings are not proprietary. The input/output ports are standard J1926 straight-thread fittings. If the fitting and o-ring are correct, you tighten up the fitting and it bottoms out, compressing the o-ring, sealing the port.

See this site for examples
https://www.discounthydraulichose.co...hread-orb.html

Earlier this week I confirmed my suspicion that the o-rings are standard, found matching o-rings at McMaster-Carr, and tested them in my Racor 500. Perfect match without the extraordinarily-perfect price. For fewer than $2.00 you can have a most of the o-rings needed, instead of the $40 price tag for "Racor Seal Service Kit - RK 1521". I did not find a match for the beveled

I added details and uploaded supporting documents, including my cross-reference sheet for Racor/McMaster.
https://pearson365.com/forum/index.php?topic=2107.0

[svtrio]

Scherzoja,

I’ve been wrestling with this issue and I’m really grateful that you shared the results of your work with us on the forum.

Svtrio

[jpendoley]

I ordered the fittings thru Defender-they are Racor fittings and they were ridiculously overpriced. I did tighten them, but at a certain point the fitting turns and the resistance doesn’t change-my assumption was that continuing to turn would cause o ring extrusion and leaking. As of now, the leak is very slow, more like a weeping leak so I am thinking that pipe sealant might be the next step (which, interestingly, Racor recommends).

[Chotu]

I may have botched my filter change when stupid from hunger and posted about it, but I’d always use pile sealant on every single fitting I ever tighten.

It’s necessary.

[SV Bacchus]

Due to a tank of excessively bad fuel and being in the islands under Covid lockdown, I had to disassemble a Racor 500 twice. The inlet and check ball inside the housing but prior to the filter was plugged solid with a mass that looked like an oyster!

Both times I disassembled I never replaced an O-Ring as I had none and I never used sealant or tape on the threads. I tightened the fittings pretty tight with a wrench and no leaks, either time. That is no leaks, at all, when reassembled; never had to go back and correct a drip or seep. Same held true for the compression fittings.

Was I lucky? I doubt it, never had luck on any of my other repairs!

I think they are made to be tightened down tight as mentioned earlier in this thread.

[a64pilot]

Why would anyone put thread sealant on an O-ring seal?
So far as still turning after being tight, I assume you have the 90 degree fittings?
No one ever said O-rings are proprietary

On edit on an O-ring seal fitting the O-rind does the sealing, the threaded portion hold the Assy together.

[Midnight Son]

A64 +1

[Dougtiff]

Being a retired commercial diver, and also responsible at one time to build diving system's, like diving bells and decompression chambers, lots of O rings being used on various equipment, never use any sort of thread sealant for various reason's.

[jpendoley]

This from Racor manual. Mine is weeping-I did not use sealant, but maybe the engineers at Parker know something about diesel.

These customer supplied materials should be on hand before beginning installation.
• Shop Towels
• Mounting Hardware
• Inlet/Outlet Fittings
• Fuel Hose
• Clean Diesel Fuel
• Parker Super O-lube or Clean Motor Oil
• Thread Sealant (no thread tapes)

[Midnight Son]

Originally Posted by jpendoley

This from Racor manual. Mine is weeping-I did not use sealant, but maybe the engineers at Parker know something about diesel.

These customer supplied materials should be on hand before beginning installation.
• Shop Towels
• Mounting Hardware
• Inlet/Outlet Fittings
• Fuel Hose
• Clean Diesel Fuel
• Parker Super O-lube or Clean Motor Oil
• Thread Sealant (no thread tapes)

I'm pretty sure they mean the thread sealant for the other end (JIC end of the fittings).
Best wishes

[Pauls]

The thread sealant is to seal the THREADS where they screw into the filter. O-rings never use a sealant. The compressible rubber is the sealant. A little oil on the o-ring is a good thing.

O-ring seals cannot be damaged by "overtightening". The o-ring sits in a groove whose depth is typically 80% of the o-ring thickness. When you tighten the fitting the metal faces of the fitting come into hard contact and the o-ring, in its groove, is compressed 20%. You can't harm the o-ring by overtightening.

[OloteleMtn]

As a marine and industrial mechanic, i repaired lots of assemblies with O rings damaged by over tightening....your mileage may vary.

[Pauls]

If that is the case then you have had the misfortune to deal with poorly designed or machined components. As an engineer who has designed hundreds of o-ring sealed things and has built and maintained many of them, a correctly built o-ring seal cannot over compress the o-ring. This is inherent in basic o-ring design logic.