Real Time Help Needed - Air Brake Leak - 4106 W Spring Brakes

[travlinman]

Hey Guys need some help!

I am southbound on highway 97 at the Oregon/Cali border when I start dumping air. Pulled off the road and located the leak. It is coming from the "Shuttle Exhaust" portion of my spring brakes. Specifically from the plumbing type tee below the "Shuttle Exhaust" itself.The leak only happens when the spring brake knob is pushed, in otherwise nothing. The brakes will not release now. I am in an OK spot but it would not hurt to be able to move the bus. In the first photo the "shuttle exhaust" is on the left. Second photo it is on the left as well. Third photo shows one of the spring cans and a bus nut!

Any and all help would be appreciated!

TM

[travlinman]

Photo 2

[travlinman]

Photo 3

[Hard Headed Ken]

I'm sure someone will have a better answer, but in mean time you can be looking through your toolbox for the special release bolts.  If you end up having to use them BE SURE TO SCOTCH THE TIRES!!

Ken

[belfert]

Scotch the tires?  Is that the same as chocking them?  I always carry four wheel chocks in case of some sort of emergency.

If you can't maintain enough air pressure to release the spring brakes I would not want to drive the bus if you could release the spring brakes.  Sorry I can't help with fixing the actual problem.

[luvrbus]

bypass the valve spring brakes don't need that to operate hook up directly to the rear relay did you do the plumbing on your bus ? if you lost a spring brake just cage it and plug or tie the lines together that will get you down the road to a place for repairs or parts

good luck

[zubzub]

I was going to say something like Clifford said.  I looked up the shuttle valve, can't exactly work out why you need that on a bus.  you can plumb the springs with air from anything, if you can control said air you can control the spring brakes.  Fer instance...if my rear relay for the spring brakes went out and i was stuck, I might disconnect the  line from the relay "in" and connect it with a "t" to the 2 lines heading to the spring part of the rear brake, with this I could still control (slowly mind you) the spring brakes using the button in the cockpit.
This is just a get it to safety solution, and don't do it if you are also having problems with your service brakes/relay.  Often the service brake and parking/spring brake are incorporated in one big relay valve....this would make bypassing the spring side a little more complicated....Make sure you know what you are doing.  Also as others mentioned, if you can find the captive bolts for the springs brakes you can disable them 'til you are where you need to be, but this not wise or recommended and if you did imagine doing it, make sure you have plenty of air pressure and  if you are losing pressure, stop the bus.

[travlinman]

Hey guys;

Thanks for the replies. Here's an update: Managed to get to Napa just before closing to pick up a new shuttle valve. Jury rigged it in and got the bus to move. We are in a safe location for the night. The air lines are shot, so I will have to wait until tomorrow to replace those. But it looks like I have a potential bigger problem. If this is in fact plumbed incorrectly, I guess I need to redo it. Any tips on how?

TM

[zubzub]

FYI I just said I don't know why it has a shuttle...doesn't mean it doesn't need one, just that I don't understand why it needs one.
 Also your pics make it hard to see/comprehend how your system is assembled

[Hard Headed Ken]

Scotch the tires?  Is that the same as chocking them?  I always carry four wheel chocks in case of some sort of emergency.

If you can't maintain enough air pressure to release the spring brakes I would not want to drive the bus if you could release the spring brakes.  Sorry I can't help with fixing the actual problem.

It seems they mean the same

scotch (skäc̸h)

transitive verb
to block (a wheel, log, etc.) with a wedge, block, etc. to prevent movement

Origin: earlier scatch < ? OFr escachier, to crush < es- (L ex) + VL *coacticare: see cache

noun
such a block, wedge, etc. used to prevent rolling, slipping, etc.

chock  (chk)
n.
1. A block or wedge placed under something else, such as a wheel, to keep it from moving.
2. Nautical A heavy fitting of metal or wood with two jaws curving inward, through which a rope or cable may be run.
tr.v. chocked, chock·ing, chocks
1. To fit with or secure by a chock: The plane's wheels were chocked and chained down.
2. Nautical To place (a boat) on chocks.
adv.
As close as possible: had to stand chock up against the railing.

[kyle4501]

The shuttle valve is needed to allow the brakes to release quicker - otherwise, all that air will have to exhaust thru the dash valve.That will be messy & noisier up front . . .

[zubzub]

but that is what a relay does...or are we calling a relay a shuttle valve?

[kyle4501]

shuttle, relay, quick exhaust. . . . . can be the same thing, just depends on what it is being used for. 

[luvrbus]

Quick release guys but springs need air to release they don't necessary need one,hate to say it but that is not a neat plumbing job the guy has with the galvanized fittings

[travlinman]

Awesome information - love it!

OK, so the plan for tomorrow is to replace the crapped out air lines and lose the galvanized fittings - brass only. Anything else I should be thinking about while I am under the beast? I already know beer is at the top of the list when I'm done.

Clifford, no I did not plumb it but I would like to make it right now. Any advice is much appreciated.

HHK, yes the tires were scotched. Thank you for expanding my vocabulary.

TM