Quest For Air Leaks-Have a Question

SuiteSuccess · November 7, 2016

Gonna start my yearly quest to find and repair air leaks especially in light of my recent increased frequency of cycling of my air compressor. I'm using an external air compressor to pressurize my tanks and system either through a Schraeder valve on the the governor or more likely using Charlie Lord's air conditioner connector idea pre-air dryer. The question, other than monitoring the gauges should I leave the key in the "ON" position while the compressor is connected? I plan on leaving the compressor attached with max pressure set at 125psi.

Jeff.Sloan · November 7, 2016

We have a male quick connect fitting as the drain valve on the front of the three air tanks, with a female mated to it with a plug. Allows it to instantly connect to my 80 gal air compressor when needed. It charges the whole system up, no problem. All the self levelers work with the ignition off, no need for the key to be on. Sometimes I leave the truck stored with full air to reduce the 'deflation' fatigue on the air bags. (my compressor kicks on 1-2 times per day when I do this)

RandyA · November 8, 2016

Carl, I was recently told that when using the "Whisper" we should chock the wheels so the truck will not roll and release the service brakes so that we can check for leaks around the brake cans. Also have a second person press and hold the brakes while checking cans, valves and air lines to brakes. Sounds good to me so I have that on my to-do check list. The only part of the system I know of that will only work with key on is the dump valve for the rear air bags so I believe "key off" is fine for checking.

I think your truck has air bags on the front? Be sure to check for leaks all around the front bags, then the cab bags and of course the rear axle bags. hose fittings are on top of bags, cracks that leak can be anywhere.

Jeff has a good idea/solution. While the forward wet tank outside valve does not make for a good outgoing air connection ( must use the back drain valve on same tank for that) pumping air into the outside drain valve on the front tank should provide air service everything else. I think I will follow his lead and add a fitting there.

sclord2002 · November 8, 2016

Carl, the connector is a R-134A high side connector. The low side connector is smaller. Let us know what you find. Charlie

Jeff.Sloan · November 8, 2016

Thanks! Don't give me too much credit ;-) The truck was this way when I bought it - but it sure has come in handy!

SuiteSuccess · November 8, 2016

Thanks Charlie, Jeff, and Randy. The connector Charlie refers to above is pre-air dryer. That way I don't have to buy any extra accessories for my pancake compressor to put only dry air in the system. Am I correct that the air dryer is a passive system?

RandyA · November 8, 2016

Thanks Charlie, Jeff, and Randy. The connector Charlie refers to above is pre-air dryer. That way I don't have to buy any extra accessories for my pancake compressor to put only dry air in the system. Am I correct that the air dryer is a passive system?

Are you looking at the connector on the metal pipe that runs from the compressor around the front of the engine and then turns back on the left side to the dryer? Humm....... I knew it looked like a R134A connector sticking out on the hard line but never tried it for size - just figured it would be different so some one didn't try to hook up his A/C gauges there.. You know, that Charlie is a pretty smart feller. It is mighty hard to pull the wool over his eyes :lol: . How do you plan on making up the needed R134A female high side connector to go to your air compressor?

SuiteSuccess · November 8, 2016

Are you looking at the connector on the metal pipe that runs from the compressor around the front of the engine and then turns back on the left side to the dryer? Humm....... I knew it looked like a R134A connector sticking out on the hard line but never tried it for size - just figured it would be different so some one didn't try to hook up his A/C gauges there.. You know, that Charlie is a pretty smart feller. It is mighty hard to pull the wool over his eyes . How do you plan on making up the needed R134A female high side connector to go to your air compressor?

http://www.ebay.com/itm/New-Refrigerant-R134a-90-Degree-Quick-Connector-Adapter-Coupler-Air-Conditioning-/371725738331?hash=item568c94a15b:g:AVYAAOSwGtRXyTXI

Bought some like this, then 3/8" quick connect male with several wraps of Teflon tape to "snug it up" in the threads.

SuiteSuccess · November 10, 2016

Well found my leak and reason for compressor cycling. Coming from driver's side front air bag and is signicant with leak rate of 20psi per minute. Spoke to my good friend Charlie (sclord2002) and he said easy change out. Will get it done soon. Any words of wisdom or gotchas?

Randyretired · November 10, 2016

I changed the rear airbags on my truck. Pretty straight forward. It required removing the tires and wheels. That was the most difficult part. If one is leaking you might want to replace the others if it has been awhile.

MrSeas · November 10, 2016

Did you check the front leveling valve(s)? (some have one leveling valve and some have two)

Easy to change out....

Make sure you get the correct Part # for your setup.

Think about changing out the air line fittings while you have it apart.

SuiteSuccess · November 10, 2016

I changed the rear airbags on my truck. Pretty straight forward. It required removing the tires and wheels. That was the most difficult part. If one is leaking you might want to replace the others if it has been awhile.

Actually both front bags were changed out when I bought the truck 6 years ago. Mine is accessible without taking off the tires and wheels.

Did you check the front leveling valve(s)? (some have one leveling valve and some have two)

Easy to change out....

Make sure you get the correct Part # for your setup.

Think about changing out the air line fittings while you have it apart.

Thanks, will do.

sclord2002 · November 14, 2016

Carl, did you air up the truck with the engine driven compressor first or did you just go for it with your pancake compressor ? I questioned if the pancake would push enough cfm to enable you to find the leak without starting with a full load of steam, so to speak. Anyway, I am glad you found the culprit. My front air bag was amazingly easy to change.....hope yours is the same. Charlie

SuiteSuccess · November 14, 2016

Charlie,

Popped the hood before I got started and then aired up by starting truck so I could turn front wheels for access. When I shut truck off heard loud hiss in front driver's side. Got under truck and sure enough seemed to be air bag. Didn't have to use pancake. Also found one of my ET connectors is leaking so will fix that also. Going to try and remove air bag today and order new one. Volvo doesn't have one in stock so will try KW, Pete, and Freightliner dealers. Couldn't effectively check brake cans per Roger's recommendation because truck leaks down quickly, but will try again after changing air bag.

Jack Mayer · November 14, 2016

The ETs tend to leak in the fitting going into the bag from underneath. You can get to it with a thin-wall socket. Replace it - dope it up good - and you will solve the issue, if that is where the leak is.

SuiteSuccess · November 14, 2016

The ETs tend to leak in the fitting going into the bag from underneath. You can get to it with a thin-wall socket. Replace it - dope it up good - and you will solve the issue, if that is where the leak is.

Thanks. Gonna replace the t-connector also.