Jeff , That is a ride height control valve. It’s important to determine exactly where the leak is. Is the valve leaking or the plumbing? Get the area as clean as possible and start by spraying soapy water.
1993 Newell (316) 45' 8V92,towing an Imperial open trailer or RnR custom built enclosed trailer. FMCA#232958 '67 Airstream Overlander 27' '67GTO,'76TransAm,'52Chevy panel, 2000 Corvette "Lingenfelter"modified, '23 Grand Cherokee.
I just changed out a ride height valve for one of our Guru's and leak he had was from the vent which is normal, they will bleed a tad bit of air when the coach is turned off but it should stop after everything is settled, like Dean said make sure it's not just bleeding off then stops or it's a fitting thats leaking.
After rereading the OP post, I realized the question is about the elbow fitting which should be a 1/4" Male NPT to 1/4" tubing like this Push Fitting . Those fittings are easy to replace but will eventually leak again. Many Gurus will replace the fitting with a compression fitting like this Compression elbow . I go a slightly different direction and install a Street Elbow like this Street Elbow and a straight compression fitting like this 1/4" Compression Fitting . Most hardware stores have 1/4" Brass Elbow and 1/4" Brass Sleeve which will also do the job.
Jim
2014 Newell Coach 1482 Mid Entry 45'8" Valid Slides and Valid Levelling
Most hardware stores will sell fitting that are not DOT, threads on the nut are different, makes it harder in the work on in the future, the PO for 712 use lots of hardware store fittings
