Splicing air lines.

DOT approved push to connect fittings will have stamped into them, usually on the ends, "DOT". "Compression" type air brake fittings will either have "DOT" or "AB" stamped on the nut. The nut will have "rounded" ends, the ferrule or sleeve will be tapered with a raised ridge in the middle.

You are correct. If it is a primary line to primary or secondary air tank they can not be spliced. Same goes for any line going to brake valves and brake canisters.

WILDEBILL308 wrote:

FIRE UP wrote:
Well Gang,
Yep, I have to agree with the "Push on" type. The Freightliner chassis under my coach is loaded with them. Now, I will admit that about 99.9% of them are at solenoids or mounted fittings of some sort but, non used for "Splicing". But, if I had to do what the OP had to do, I'd use the push on/in type all day long. In fact, I plan on adding a short line to the shrader valve on the bottom of my coach and run it to just inside a nearby compartment.

My coach looses about 10 lbs. of air a day, while parked in it's home, next to our home. Every once in a while, I have to crawl under it and feed it some air, to bring it back up to normal height. So, I'm planning on using those push-in/on types when I construct this little addition.
Scott

Why do you feel you have to add air? Just dump the air and leave it it will set on the stops till you start it and get ready for the road. Why do you crawl under to add air? there should be a air chuck in the front above the generator that the wrecker hooks into your airline to release the parking brake so it can be towed.
Bill

Bill,
Well Sir, without hijacking this thread about the OPs question of splicing air lines, I'll briefly explain why I do what I do. You see, we park our coach indoors, inside an RV garage which, is attached to the two-car garage. It's a brand new home. Because this coach does loose air, it will over a week or two, loose almost all the air. Now, you and I and just about every one else who has a diesel coach, knows that low air means the brakes are set and, you cannot release them until a proper amount of air is built up in the system.

So, what that means is, the upon start up after sitting for a couple of weeks, the engine needs to run for quite a few minutes prior to the ability to release the brakes so, I can move it outside the RV garage. And, what that means is, I'm filling the inside of that RV garage and the two car garage next to it, with diesel smoke and all that smell.

I only let that rig sit about two weeks maximum without starting it and moving it outside so I can mop and clean the floors of both garages.

But, if I know I'm going to move it out side and, the air system is really low, I creep under it, remove the cap to the shrader valve and fill the system enough so that I can start the rig, immediately release the brakes and, move it outside without running it too much indoors.

Now, as for your statement about "there should be an air chuck up front", you are correct. But, I'm not going to say you're wrong in what you say, I'm only going to say what "I" have to do to fill that air system if, it drops waaaaaay down to say, oh around 20 lbs. or so. You see, if that system drops below 65 lbs., there's a check valve some place that prevents filling it, (at least on my coach) by using that air chuck in the front of the coach. I know because I've tried it several times. It will NOT fill when it's that low.

But, if I crawl under it and, use the shrader valve on the base of the air drier, it will allow me to fill the system completely or, I can fill the system to somewhere "over" 65 lbs. and, then, I can go up front and utilize that air chuck you mentioned, and finish filling the system to 120-130.

Now, again, I don't know if or, how different my air system is from anyone elses but, I've proved that method, several times. I've lowered the air pressure by pumping the brakes, 'till they set themselves. Then I've tried to fill the system using that front air chuck, NOPE ain't happening. And, to prove my point here, a buddy's Vectra of the same model year, '04, with the same engine, a C-7 CAT, died and wouldn't start while camping in the Sierra Nevada mountains.

A wrecker came to tow it to a diesel shop to get it to run. I was not there, at the time. The driver of the Wrecker, attempted to fill the air system via the front air chuck. He couldn't fill the system enough to release the brakes. He apparently did not know about the one on the air dryer. He tried several times.

Anyway, that's why I do what I do.
Scott


" A better question is why do you lose 10 lbs of pressure a day? Mine rig often sits for 3 weeks at a time and I have no noticeable ride height change and very little (if any) pressure loss on the gauges. Rather than adding a fill connection, I would look for a leak with soapy water and fix that. Good luck."

Lou,
I most certainly agree with you on, search for the air leak and fix it. I spent most of my career under fire trucks, (as well as driving them and operating them) doing things like searching for air leaks, water leaks, oil leaks, and more. It's a pains taking operation to try and follow every inch of air line(s) from front to back, up and over axles, Omni-directional around valves, fittings, around wire looms, and much, much more, in search of an air leak.

It is good that yours is more sealed then mine is. I envy that. But, mine is what it is. Maybe some day I'll finish ALL of my projects and then, climb under that coach, and start searching for the leak. It may be that I'll find it in 10 minutes, or, I could be under there for days, who knows? But, in the mean time, based on the explanation above to Bill, if I take a 1/2 day, create that little air line, from the shrader on the air dryer to an accessible compartment, only a couple of feet away, I can fill that system without getting under the coach. And, so can a wrecker, if and when the need ever arises and he has to fill it. Hope this explains why I do what I do.
Scott

Sorry to the OP, certainly did not mean to hijack the thread with my explanations.
Scott

Thanks for all the positive replies regarding push-on fittings.
At this particular time I am going to splice the lines with DOT approved fittings.

From what I can see underneath and through the floor in the bedroom, it will take many hours to trace where all the lines go.

I'm not even sure I can find where the lines are that go to the front, but I'll try and figure it out.

I think I need to find a contortionist monkey to help me:)

Fire Up: I have always been anal about air leaks. When I started driving long haul part time I was amazed at how many trucks would leak down to almost 65 lbs. overnight. These were all late model trucks. The maintenance guys would give me a strange look when I complained. The answer I would get is that some vehicles can hold air for a week and others maybe a day. The DOT requirement for leaks is liberal. Part of the brake test is to shut off the engine, block the wheels and build up air. With park brake off you hold down the brake treadle for a minute. For a bus you can lose 3 psi in a minute. So in 40 minutes you would be out of air. Keep in mind this only tests the brake system. There are lots of other places where leaks occur: leveling valves, air suspension and even lines to the air horn. As you stated finding the air leaks is a daunting task.

Moisheh

moisheh wrote:
Fire Up: I have always been anal about air leaks. When I started driving long haul part time I was amazed at how many trucks would leak down to almost 65 lbs. overnight. These were all late model trucks. The maintenance guys would give me a strange look when I complained. The answer I would get is that some vehicles can hold air for a week and others maybe a day. The DOT requirement for leaks is liberal. Part of the brake test is to shut off the engine, block the wheels and build up air. With park brake off you hold down the brake treadle for a minute. For a bus you can lose 3 psi in a minute. So in 40 minutes you would be out of air. Keep in mind this only tests the brake system. There are lots of other places where leaks occur: leveling valves, air suspension and even lines to the air horn. As you stated finding the air leaks is a daunting task.

Moisheh

Moisheh,
I'm not "proud" of having an air leak on this coach and, I'm in no way, lazy when it comes time for maintenance. If anyone's ever read my threads on any of the maintenance or repairs I've done on this coach, they're all proof positive about me not being lazy. But, based on the fact that the loss rate of air on this rig is not all that bad and, it's not that hard to supply air to it while it's parked in the barn, I've simply not jumped on the search for the leak.

I will, at some point in time but, not just right now. And yes, as part of being a Engineer on the Fire Department, we had to know all the rules and regs on specs for air systems, leak down tests, build up tests, timed leak downs, pressure tests, static tests and much, much more. If this rig would loose 90% over night, that kind of leak would be easy to find, even with my really bad HEARING!

I'll get to it, someday.
Scott

Scott I think the best/easiest thing for you is to run that line so you don't have to crawl under the coach to add air. My coach doesn't have a nice warm garage to sleep in. I know you are aware of the recommendation that if you start a coach it should be driven for about 25 miles to get everything up to temperature. Otherwise it is better to not start one. Have you thought about running a exhaust vent to pull the exhaust out of the garage when you start it?
Bill

WILDEBILL308 wrote:
Scott I think the best/easiest thing for you is to run that line so you don't have to crawl under the coach to add air. My coach doesn't have a nice warm garage to sleep in. I know you are aware of the recommendation that if you start a coach it should be driven for about 25 miles to get everything up to temperature. Otherwise it is better to not start one. Have you thought about running a exhaust vent to pull the exhaust out of the garage when you start it?
Bill

X2,I was just going to make the same suggestion. Besides on most of the school buses I drive,the E brake doesn't pop till it's below 65 #s. We are required to do a tap test EVERY time a bus is used the first time that day and as I'm a substitute driver,ten + years as a regular before retiring the second time and now 5 more as a sub after being begged to come back,I will do the test even if it's been used that day by another driver. I usually do it every day in the motorhome when I'm on the road and boy,do I get some funny looks from other owners sometimes..

BIGDOG & WildBill,
Yes Sirs, I have thought of an "exhaust outlet". In the FD, we had "traveling" exhaust accordion tubes that clamped onto the tip of the exhaust of the fire truck. That way, when you started the rig, everyone jumped on and, you headed out the barn, the tubing would just "self-disconnect" from the exhaust due to the fact that the magnetic connection was not strong enough to damage itself and or, the tubing.

But, I've looked into portable exhaust extraction units and, some are, well, "Kind-a" in reason, in terms of price. But, I've also thought of just cutting a hole in the outside wall and run the tubing through it. But there's a couple of problems associated with that. One, the exhaust pipe, is on the passenger side rear corner and, the outside wall of the RV garage is on the drivers side.

So, what that means is, I'd be tripping over that thing every minute I'm in there tinkering around as, the portion of the RV garage right behind the coach is my PROJECT area where, I do about 99.9% of my tinkering, projects, jobs etc.

So, as stated, I will at some time try and do a diligent search for this leak. But, not at the time. So, by adding that little auxiliary air fill line. It will enable me to keep the coach's air system up much more efficiently which, will allow me to almost instantaneously pull it out, within 15-20 seconds or so after start up.

At that point, I can close the RV garage door and let it run 'till full air is built and or, just simply take off for a cruise of the Lake Havasu area so it warms the beast up proficiently. I do thank you two for thinking of a remedy for this situation. Much appreciated.
Scott