Air line size needed between air tanks??

Gary LaBombard · January 06, 2008, 05:36:04 AM

Hello Everyone,

Believe it or not I am in the planning stage of putting new STUFF back on my bus after 5 years. Most of all the reinforcing & reframing of the undercarriage is done now and hopefully no more undercarriage work will ever be necessary.

What I am trying to do is accumulate the things I plan to start soon and one is reinstalling all my new air lines, valves etc. My question here is the air lines connecting the 5 air tanks I will have, (one wet tank, two torpedo drive brake tanks, one front wheel brake tank and one "SPARE" in line tank used primarily for my windshield wipers. I know, I know, electric wipers is better way to go, but the the bucks have to be spread more thinly here to do all that is really more important for safety. Anyhow, my question is what size DOT plastic air line is recommended for filling between all the tanks? (1/4 - 3/8) or what do you recommend? I want to start getting the appropriate check valves and all parts needed for the air system but this baffled me as to the size needed between the air tanks for filling etc.?

Thanks ahead of time, as I start putting back new parts I hope to ask your advise and this is now getting to the fun part of a conversion (putting stuff back on)!! The $$$ part not so much fun!! Sonnie, now is the time I could sure start to use your expertise.

Gary

JackConrad · January 06, 2008, 05:43:17 AM

Gary,
I think you will find that different sizes are used, depending on what that tank supplies (larger volumes of air require larger lines). Do you still have the old fittings in the tanks? These might give you a clue as to what size tubing to use. Jack

PS: Thanks for posting Mom's photos on youir photo albums, She really got a kick out of seeing that and I sent a link to my brother.

Stan · January 06, 2008, 05:46:33 AM

I think the original lines on MCI were 5/8". HTH

jackhartjr · January 06, 2008, 07:42:23 AM

Sonnie, now is the time I could sure start to use your expertise.
Who's Sonnie Gary?
Thanks, and congrats on start the fun part!
I'm so new at this it's all fun right now!
Jack

buswarrior · January 06, 2008, 08:19:34 AM

Hello Gary.

Between tanks, a larger line will allow the air to travel to the tank that needs it more quickly.
So, bigger or equal to the lines that take the air away from the intended tank, can't go as wrong here, unless you pick too small.

The tricky bit is the delivery lines.

Length, diameter, bends and fittings all play a part in the timing and strength of a brake application.

You want to be very careful what you do with the lines between the treadle valve and front brake chambers, the line from treadle to relay and between the relay valve and the rear brake chambers.

They need to be faithful to the origianl design, or you will not get the proper performance from the brakes, uneven application, side to side or front to rear, too slow or too fast application and/or release.

happy coaching!
buswarrior

JackConrad · January 06, 2008, 08:57:05 AM

Quote from: jackhartjr on January 06, 2008, 07:42:23 AM
Sonnie, now is the time I could sure start to use your expertise.
Who's Sonnie Gary?
Thanks, and congrats on start the fun part!
I'm so new at this it's all fun right now!
Jack

Sonnie Gray (AKA Catskinner) is a gentleman in Texas with a beautiful Eagle conversion with a big Caterpillar engine. Jack

Gary LaBombard · January 06, 2008, 10:34:19 AM

And Sonnie Gray is certainly my converter hero. I will see If I have the air schematics, which I should of done in the first place, Dahhhhh!! Thanks for the tips as usual. I hope you are staying nice and warm up there in Beautiful Canada Ewen!!

Jack, I do not have all the original tanks or fittings any longer as this rusted out stuff all took up room in my shop area and that was over 5 years ago. My bus only had 3 tanks as well as they took out 2 of them, no tanks in the front for the front wheel or wiper?? Everything in the front was supplied off the main wet tank!! I had holes behind the brackets holding the two drive wheel air supply tanks. No wonder the air compressor never shut off in the 100 miles I drove it!!!LOL

Anything I do will certainly be a much safer situation I believe.

Thanks to all again,
Gary

Catskinner! · January 06, 2008, 11:06:23 AM

Gary

I used 5/8" on all of my air lines when I re plumbed all of my
air tanks. This was the original size from back to front so
this is what I used between all tanks. I used a diagram
from a tractor setup and it was all color coded which helped
out a lot. I think it was a Bendix diagram that I picked up
from a truck parts house. They are normally on the service
counters. Gary hope this helps, or call me if I can help you.

Catskinner!
Sonnie & Patti Gray
72 0/5 Eagle 3406 Cat
Pottsboro, Texas

gene lewis · January 06, 2008, 02:14:07 PM

Gary,

I have just gone through my Eagle Parts Book and Eagle Manual and I cannot find the sizes of the fittings and lines.

I want to say that the lines connecting my two air tanks in the rear are 3/8". I do know that I installed a 3/8" copper drain line from each tank coming out in the wheel well. Put a brass valve right out at the edge of the wheel well so I could drain the moisture easily.

All the air line on my Eagle are copper, steel or braided metal over rubber. I have yet to find any plastic lines on my Eagle.

Its a grand feeling to start putting it back together. I did not strip mine to the point you have stripper yours, but I do remember the GOOD feeling that came when we starter back up. Fun days!!!!!

To me this is exciting news. Congrats.

Call me if I can help you.

Enjoying the journey from NC,

Gene 05 Eagle

belfert · January 06, 2008, 03:22:37 PM

My bus is a 1995. I'm not sure what the main air lines are made of, but all accessory lines are plastic. The line from compressor to the air dryer is rubber. (Can't recall if braided or not.)

Gene, I suspect plastic either was DOT approved when the 05 was made or nobody trusted it yet.

Gary, I highly recommend installing an air dryer if you don't have one already.

NJT 5573 · January 06, 2008, 04:22:49 PM

Gary, What Sonny said about the Bendix truck schematic is right on. I think you can throw alot of air valves away and run all your service brakes from the treddle valve into one R6 valve. The R6 has 6 out ports, one for each diaphram. You should keep a tank to pull the spring brakes off in an emergency. Ca requires it.

If electric wipers were better, they would all have electric wipers.

Plastic DOT will save you alot of money and unlike Aeroquip it will last forever. The only problem I have ever had is welding around it, but super glue seems to make a lasting repair.

Sappony Eagle · January 08, 2008, 05:00:38 PM

Hello Gary, I'm Ken Munford ,we talked on the phone about a year ago about fuel tank removel and we also talked about up dating our brakes to the dual brake system. If I remember correctly no one wanted to help you with that. Well, I just finished doing mine and it was a job. If you are still interested E-mail me kenmunford @yahoo .com and I'll give you me phone # and I'll tell what I did.

Gary LaBombard · January 08, 2008, 05:59:36 PM

Ken, I had to send you a MAK personal message back to you as your email address in your profile sent it back to me. Thanks for the contact and remembering me from last year's conversation. I look forward to us talking.

Gary

Sappony Eagle · January 09, 2008, 06:49:26 AM

Hello Gary, Sorry about that. My profile was not up to date. My e-mail in ken munford@yahoo.com.Phone # is (804)744-0065

compedgemarine · January 09, 2008, 06:00:26 PM

try the Bendix commercial site and download the air brake handbook. dont know if it has the line sizes but does have lots of useful info. http://www.bendix.com/en-us/service/library/Pages/Home.aspx if all else fails contact them and I am sure they have a tech service.
steve