OBA -> On Board Air Mega Thread & BS

If the check valve is oriented correctly then any back bleed through he compressor should last only a few seconds at most. A check valve is just a ball bearing and a spring but they can still leak if the bearing is corroded or there’s a foreign body lodged. If the check valve is backwards then you get no air past it so it should be obvious.

 

The check valve was always oriented properly; it's worked ever since I installed it. Now, my OBA system has had a mysterious bleed-down problem for a couple of months prior to the relay failures that I could not pin down. Maybe I finally discovered the problem.

I ordered a new check valve. Stay tuned...

 

Me again.

OK. Replaced the check valve but I am still having the same problem. Now, are all Check Valves more-or-less the same? Or are their special Check Valves for air systems (as as opposed to liquids)?

This is what I installed:

$16 Control Devices P2525-1WA Brass Ball Check Valve, 1/4" NPT Female x NPT Male

https://www.amazon.com/Control-Devi...7&sprefix=control+devices+p2525,aps,45&sr=8-1

 

You can get plastic ones for sump pumps. Is it brass or chrome plated brass?

 

Brass.

 

Threaded fitting leaks can be hard to spot if you can’t get the soapy water everywhere. Ptc connectors as well. But if you’re sure of all of those that leaves the tubing itself. I’ve reached the point where I do a pressurized immersion test to spot problems before install and also switched to compression fittings instead of ptc.

 

Likely an air fitting then.

 

I've done the Soap Suds test on all my fittings. They don't indicate any leaks.

I guess I'll keep looking.....

 

Try slightly more soap or less water to increase the viscosity. Or not use windex as the alchohol also interferes. It might make the bubbles persist longer and get bigger. If they form on a side of the fitting you can’t observe directly they could be forming and popping out of sight.

 

I use water and dishwashing soap. No Windex or alcohol.

I'm also going to try letting the compressor pump the tank up to full pressure, then disconnect the fitting on the compressor-side of the check valve. Then soap up the check valve and see if I am am getting any back flow.

 

Do you have a drain valve? Those can leak since they’re prone to getting fouled.

 

I do.

I'll check it as well.

 

Good luck with it. Finding them can tax the patience.

 

OK.

There is no backflow through the check valve. Yay!

Found two more small leaks. Boo!

Fixed them both. Yay!

Checked the drain cock on the tank. No leaks. Yay!

Still have a small leak somewhere. Boo!

But the bleed-down is not as bad as before. Yay.

Still have one connection to check but it is in a very inaccessible location. Boo!

Will tackle that one tomorrow.

 

Read through most of this thread, bud didn't find my answer so I will ask a fresh question.

My ARB twin has been under hood for less than a year and working awesome. Just recently it is giving me a very high pitch/squeal sound after it warms up during use. So, it's not there during the first several cycles. Damn it's loud!!!

The squeal only happens just before it triggers off at max PSI. I am leaning toward the pressure switch being the culprit, unless anyone has another suggestion?

 

So I'm finally gathering parts to hard mount my smitty 2781. Currently looking for a relay/solenoid that can handle atleast 50A. I've been looking in the 80A range, but it seems like every relay or constant duty solenoid I can find on the internet have bad reviews, most including claims of getting extremely hot or failing pretty fast. Is there a go-to relay/solenoid that you guys have used? I'd like to hear what options people have had some good luck with, especially if you have experience with operating it in cold (sub 32F) temperatures.

 

Have you considered this one?

$29 Fastronix 50/30 Amp Weatherproof Automotive Relay and Socket Kit

https://www.amazon.com/Fastronix-We...t=&hvlocphy=9032898&hvtargid=pla-568736851419

 

I've been looking at the ones that use posts instead of leads or tabs because I need to use 4 gauge wire. I should mention I'll be running it from the battery to the bed, so I have to use the thick stuff.

 

I ran this directly off my arb twin. I was fine for a while but after filling 4 35’s and 2 32” tires the fitting melted blowing the line out. Switched to a viar stainless braided hose for 16 to a distribution block. Haven’t checked the temps there but you may be able to run it after a set distance.

 

I haven’t got around to doing this mod yet, but I did grab a stainless hose to come off the arb with. Hopefully I can get this done before wheeling season