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Old 08-11-2019, 04:38 PM
NDM NDM is offline
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Join Date: Dec 2017
Location: Midwest
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Quote:
Originally Posted by Jack 1957 View Post
After my last post a couple weeks ago, I noticed that I had leaks in my air suspension system. Horror of all horrors.. I decided I needed a couple weeks off so I shut it down and Captain Morgan and I floated around in the pool for a few days.
I was thinking about it and I think I have installed 7 air suspension systems prior to this one and never had even one single fitting leak.
When I bought this set it came with push on (Shark Bite) hose fittings. I have always used compression fittings in the past. So, 7 successful installs and 1 failure. What is the only variation?... Great, I have to change out all these fittings now.

If you look at the first picture below, you can see that the push in fitting has barbed jaws slanted inward and just below the jaws there is an O ring. These jaws have sharp edges and when you push the nylon tube in, it makes lengthwise scratches on the tube. When the tube goes into the O ring, those scratches might be deep enough to cause a leak. Also, if there is any side tension on the tube it might be putting more pressure on one side of the O ring and less on the opposite side. IDK, but what I DO know is that these fittings are going in the dumpster.

The brass compression fittings I'll replace them with are almost fool proof and will take just about any abuse you can throw at them. These hoses and fittings are commonly used in heavy truck air brake systems. Notice that the compression fitting has an inner support tube to keep from crushing the tube when tightening it down. Also, look closely at the ferrule. It has a raised rib around the OD in the middle. That keeps you from over tightening the nut and cutting into the tube. That rib will act as a stop when tightening the nut and allow just enough dig of the ferrule edges into the nylon tube to seal and hold it in place, but not enough to cut too deeply into the tube.
I'm sure some will prefer the convenience of the push in fittings and haven't had any problems, and that's fine. I prefer to avoid any potential problems so I won't be using the push ins again. Once bitten...

Best price I've found for fitttings and tube are here --> https://www.anythingtruck.com/SFNT.html

Attachment 53590


Attachment 53591

I started with the front bags. I switched out the fittings, then set the car on blocks and put enough air in to lift the car front and back. I measured from the ground up to the bottom of the rockers to see if it drops any over time. I'm going to replace all the fittings but I want to know which ones were leaking

Attachment 53592
Although I an not worthy of even commenting in your thread, I will say that those compression fittings are the absolute best in terms of leak free. There are however push to connect D.O.T. approved fittings that are very good too. I have done a very large amount of airride installs and have found that sticking to good D.O.T. fittings (never ever plastic) you will be good to go.

My second "magic cure" for leaks is loctite 565. I use it exclusively now and will never use anything else. It is immediately ready for pressure up to 160 psi and begins to cure to a resistance to I believe 3000 psi. I use it on my custom chopper airride and pretty much everything requiring thread sealant for air fittings.

Lastly, beware of valve leaks. Depending on which valves you use, they may need back pressure. I have used everything kind of valve and many require you to have a tiny bit of restriction on the exhaust valve. You also should put a check valve between the tank and the fill valve. This prevents air from "leaking" back into a tank that has lost pressure.

I would talk forever about airride with you but I want to see you get back to this amazing project! Bravo Sir!!
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