Are the delivery lines the large ones from the brake treadle valve?

[belfert]

My brake treadle valve has five lines coming out of it.  Two are 5/8", two are 1/2", and one is 3/8".  Can I assume the two large 5/8" lines are the delivery lines?

I need to install a pressure sensor on the line going from the brake pedal to the brakes.  The sensor is for a trailer brake controller.

[zubzub]

Since no one else runs a Dina here I guess my 2 cents is worth maybe 0.0002 cents, but to me sounds right (was working on my valve recently).   If it's easy to get at,  crack a connection and see. While working on my old bus I was surprised that I managed to open some fittings that had been closed for 55 years, mind you you can heat a copper and brass connection, not sure what you do with plastic other than scrap the line if it won't open.
? what the 3/8 line is, maybe supply for spring brake?

[Len Silva]

My guess would be that the largest are the supply lines from the tanks, the 1/2" are delivery to the front wheels and the 3/8 is delivery to the rear relay valve.

[belfert]

Bryce runs a Dina.  Maybe he will jump in.

The air diagrams show a delivery line going to an SR-1 valve near the front of the bus.  The other delivery line goes to the service R-14 valve in the rear.  The unlabeled line coming off the valve seems to go to the front QR-1 valve per the diagrams.

I guess I can start te bus and see which lines have air in them when the brake is not depressed.

[zubzub]

My guess would be that the largest are the supply lines from the tanks, the 1/2" are delivery to the front wheels and the 3/8 is delivery to the rear relay valve.

oh yeah the front brakes!!! Duh!  Maybe0.000001 cents.

BTW since DOT says we are not supposed to put a splice in the line, the uptight in me says you should get a "T" fitting that screws into where the 3/8" was and "T" off  from there.  The upstart in me says any time I need a splice I'll get a "T" and run a dead end into a bulkhead.

[rusty]

Most valves have the opening marked ( DEL SUP etc) Scrape the curd from around the port and see if they are marked. Also there is usually more than one port for the same chamber. You can tap into the other opening.

Good Luck Wayne

[robertglines1]

they should be color coded..as to function..don't know if it is standard colors or not.if so red=secondary     green primary&supply     yellow parking brake     blue suspension     black accesories    does not say what color brake lines are...If you use the E-15 there is two stoplight switches on the valve / top one is primary and second is secondary are connected in parallel..maybe tee into one for pressure sensor? Just some vague info ,maybe..don't know for sure.... could tee sensor into inlet side of R-14 valve in rear and trailer would brake like rear brakes

[Busted Knuckle]

Shoot I don't know which one is which as I haven't had to work on them on the Dina and it's been so long since I had to work on that blue MCI of MAK's (had to put a brake light switch on it!) while you were at our place I don't remember!
Maybe one of our air system/compressor experts will chime in!
  BK 

[belfert]

It sounds like it is not legal to use a tee in a brake delivery line these guys want me to do.  They gave me both a 3/8" and 1/4" tee and an envelope to return the unused one.

Here is a picture of what I have.  It sounds like perhaps I can just install this directly without splicing a line.

[buswarrior]

I would expect that you will have a plug in an unused port in the delivery portions somewhere on the treadle valve.

Tap in to that. The trouble with a "T" is that it disrupts air flow, and being an add on, you don't want to bother with what, if any, effect it might have.

To be really trick, you would tap in to both front and rear circuits, and, via a 2-way check valve, supply your pressure signal to your trailer controller. That way, the trailer gets the signal no matter if you have an air failure in either side of the system.

On the treadle valve,

You will have two supply lines, one each from the front and back service tanks.

You will have a delivery signal line out to the rear relay valve.

You will have a delivery line to the front brakes via that QR-1.

And the line to the SR-1 is a delivery signal from the same part of the valve as the front delivery line.

In general, signal lines push on valve internals and are smaller, delivery lines fill brake chambers and are bigger. Delivery lines will be sized to move the desired volume of air in the time required, signal lines will be sized to get the pressure signal there in the allotted time. There are exceptions, in order to get the air to arrive where, when and in the pressure and volume needed.

happy coaching!
buswarrior

[belfert]

I was able to determine that my brake valve is a Bendix E-7.  It has extra ports so I put my pressure sensor directly into an unused primary delivery port.  If my primary brakes fail I think I have bigger things to worry about than my trailer brakes not working.

[buswarrior]

No, if your primary air fails, the SR-1 will do its job, but the trailer won't be braking, so you'll be wishing that you plumbed in the trailer brakes to be activated via either side of the system in order to help get you stopped.

When last did you confirm the function of your SR-1?

happy coaching!
buswarrior

[belfert]

I verified that both the primary and secondary braking systems work seperately while I was installing the pressure sensor for the trailer brake controller.  I'm not sure it would be prudent to basically tie the primary and secondary braking systems together to supply pressure to the pressure sensor.