Air brake systems and diagnostics

[DMiller]

What you have is a Moron that had no clue set up a Trailer brake system on a truck not set up for it. Needs a TP Valve at the Rear, with GLAD Hand connections and a SECOND control Just for the Trailer. If DOT ever catches this on the road and inspects it, expect to be towed and not able to drive it until corrected.

 

[DMiller]

Truck and Trailer under DOT HAVE to be Separate systems capable of securing either machine if air pressure fails. YOURS will NOT.

 

[DMiller]

https://www.sgi.sk.ca/air-brake/-/knowledge_base/air-brake/simple-tractor-trailer-system

 

[suladas]

Truck and Trailer under DOT HAVE to be Separate systems capable of securing either machine if air pressure fails. YOURS will NOT.

If you had the work done at a shop and it wasn't plumbed legally because no tractor protection valve and the truck with air trailer cannot pass the air test, and you got stopped and ticketed, do you think the shop is liable? Even if they claimed the customer said to plumb it like that, they should refuse to do it if it's not correct right?

 

[doublewide]

View attachment 227494

The aluminum valve in that picture appears to be an R-7 spring brake inversion modulating valve.........

Yes. According to this, " R-7 modulating valve. Not inverted. I had it replaced 2 years ago June.

 

[doublewide]

......Sounds to me like you just have a gummed up check in the trailer relay valve, Just push in the parking brake, to be safe probably with the engine off and in gear so it doesn't try to roll away, then while it's all pressurized just pop the red trailer line off the quick disconnect, see if you actually are emptying the trailer tank there. If you look at the trailer brakes you may see them apply until the pressure drops too low to keep the cans extended. Relay valve failures are very common especially on a setup like this where it's really hard to keep dirt out of the open ends on the lines. YMMV

So when I got to work this morning I decided to see if maybe the shituation had fixed itself all on it's lonesome. But alass, the relay was still stuck and pissin' air. I did what you said and sure enough, air bleadin' out the red line. So, just to be a smart ass I disconnected the red air line at the valve and sprayed some WD into the valve, reconnected and charged the air system. After several applications of the trailer brakes that dang valve freed right up!

Guess I'll be ordering a new valve, at least to have on hand if the gremlins come back.

 

[doublewide]

If you had the work done at a shop and it wasn't plumbed legally because no tractor protection valve and the truck with air trailer cannot pass the air test, and you got stopped and ticketed, do you think the shop is liable? Even if they claimed the customer said to plumb it like that, they should refuse to do it if it's not correct right?

I guess they might be... What about the state inspection station. I've gone to two different places over the last 10 years. Maybe one of them might have noticed?

I'm not passing the buck. I just thought it was some old system that I just didn't understand. Ignorant you know.

 

[doublewide]

..... If DOT ever catches this on the road and inspects it, expect to be towed and not able to drive it until corrected.

Ha! Imagine the look on that DOT cops face when he came out from under that truck! Prolly bang his head on the way out to get me!

I actually went to the State Police Barracks in town here last fall to see if I could get an inspection as the DOT cop used to live right up the road from me. Guy had just retired though so I dropped it.

 

[doublewide]

What you have is a Moron that had no clue set up a Trailer brake system ......

Maybe, but I'm still not convinced that that moron was not Ford. It all appears to be too original to me. The pintle plate, trailer hand valve.

If you read the operation section of that Bendix R - 7 Modulating valve it sounds like it may be there to provide tractor protection.

Any other guys with similar vintage Ford trucks?

 

[DMiller]

NO manufacturer builds anything like this. Taking your life and the Legal way to build these as a joke now.. I am done

 

[Truck Shop]

The R7 valve does the same basic job of a SR1 valve, and neither one do the job of a tractor protection valve. that hand brake valve was generic some years back.

 

[doublewide]

NO manufacturer builds anything like this. Taking your life and the Legal way to build these as a joke now.. I am done

No need to get all bent there Mr Miller. I made an appointment this morning to take the truck in on Thursday.
Nothing wrong with a little comic relief.

 

[DMiller]

That is DANGEROUS, nothing comedy there but trying to fix it to work longer.

 

[doublewide]

I was able to identify the relay valve that controls the rear axle service brakes. A search for E6HT-2A449-AA comes up with
Bendix 103009X R-12 Relay Valve with Horizontal Delivery Ports
https://www.anythingtruck.com/product/061-103009X.html

 

[doublewide]

The foot valve... not too much luck with E0E0HT-2A270-AA.

 

[DMiller]

Standard E-7 Treadle valve.
The Ball valve on the R12 is not a factory install and DOT will not be happy it is on there.

 

[doublewide]

.....The Ball valve on the R12 is not a factory install and DOT will not be happy it is on there.

Yes sir. That will be going away promptly.

 

[doublewide]

So here's a thing. I've always thought that my trailer had great brakes. There are several small hills along my usual route and if I pick the right gear and tap the trailer hand valve I can just roll on down the hill nice and easy. So I woke up about 3 this morning thinking, how does that trailer hand valve control the trailer brakes with this setup? So when I got in to work I started getting into the dash. Based on the configuration of the valve body and the mounting brackets this valve sure looks to be factory. Then I actuated the valve. Now I know why my trailer brakes work so good....

 

[DMiller]

Because it also actuates the truck brakes. In all actuality it was installed for Just the truck brakes.

 

[doublewide]

You got it.