Airbrake hand controller 'Trolley valve' install assistance needed.

[74M35A2]

Only partial explanation so far below. "2 two-way check valves" and signal venting is what I need to better comprehend. That would be a check valve on each trailer service signal input line, but how does it vent upon release?


https://en.wikipedia.org/wiki/Relay_valve

Service brake relay valve[edit]

With a service brake relay valve installed, the hose that connects to the primary delivery-port output of the foot-valve becomes a control-line (i.e., The air from the foot-valve “dead ends” at the relay valve's control-port.). Only low-volume air-signals are required to travel back and forth between the foot-valve's delivery port and the relay valve's control port; therefore, the air-volume supplied by the delivery port is now only a tiny-fraction of what otherwise would have been required had the relay valve not been installed. This reduces the delay between the application of the front and rear brakes to only a fraction of a second. When the driver depresses the brake pedal, a small amount of air momentarily opens the relay valve's supply port, which then directs air from the remote air-supply directly to the rear service brake chambers, and quickly applies the rear service brakes. The pressure delivered to the service brake chambers in this manner will equal the control-pressure delivered by the foot-valve to the relay valve. When the driver partially or fully releases the brake pedal, the control-pressure delivered by the foot-valve decreases; this causes the relay valve's supply port to close, and its exhaust port to momentarily open, thus preventing a pneumatic short-circuit from occurring while the air exhausts from all rear service brake chambers.
In order to control the trailer service brakes, the merged outputs (i.e., merged via 2 two-way check valves connected in-series to give three inputs) of the foot-valve and trailer-hand-valve (if applicable) are directed through the tractor-protection valve, and onward towards the trailer relay valve via the blue service line. In tractors that are not equipped with a trailer hand valve, only the merged outputs of the foot-valve (i.e., via a single two-way check valve) are directed towards the trailer relay valve; however, the fact that the foot-valve's delivery-port outputs are still merged enables the trailer's service brakes to still be controlled even if there is failure within one braking circuit of the tractor.

 

[simp5782]

Ok, Quit overthinking discoball. Typical engineers flaw. If that is the case you just need to install another KN23000 or KN23010 on that T valve on the frame rail for the delivery line from the trolley valve. So it won't allow air to go up that line but only to come out of it. I pulled my vent line off it hissed very little that I couldn't even hear it with the truck off. Mine is probably not venting much either cause I have the lines on the firewall with sealer on them so they only vent slow anyway as to not let air in.

 

[74M35A2]

You're fine. I just want to wrap my head around the signal drain part. Your installation aligns with what Wiki says mostly so far, if you were to also add a check valve on the signal line from the hand valve, but it still does not explain how the heck it vents when either is moved to off. I still think the trailer brakes should be locked on after you use your foot valve, but if they are not, then great. I just want to understand how the release of it works, from either actuation.

This vid is great for explanation of an air brake relay valve, since I was studying the signal input line. Good stuff starts at 4:35. https://www.youtube.com/watch?v=f3LD8M0HKjo

What I really need to look up next is how a treadle valve drains its rear brake signal output line, and then what happens if you are putting a check valve in that line like you and Wiki says.

For others, the KN23010 is a 3/8" version of the 1/2" KN23000. Haldex also makes an all in one, 3 connections, 2 inputs one outlet, both inlets isolated. You did almost same using a tee.

What size was the stock rear trailer service line/pipe?

 

[simp5782]

You're fine. I just want to wrap my head around the signal drain part. Your installation aligns with what Wiki says mostly so far, if you were to also add a check valve on the signal line from the hand valve, but it still does not explain how the heck it vents when either is moved to off. I still think the trailer brakes should be locked on after you use your foot valve, but if they are not, then great. I just want to understand how the release of it works, from either actuation.

This vid is great for explanation of an air brake relay valve, since I was studying the signal input line. Good stuff starts at 4:35. https://www.youtube.com/watch?v=f3LD8M0HKjo

What I really need to look up next is how a treadle valve drains its rear brake signal output line, and then what happens if you are putting a check valve in that line like you and Wiki says.

For others, the KN23010 is a 3/8" version of the 1/2" KN23000. Haldex also makes an all in one, 3 connections, 2 inputs one outlet, both inlets isolated. You did almost same using a tee.

What size was the stock rear trailer service line/pipe?

3/8 " DOT.

I put KN23010 since you can't go from 1/2" pipe to 1/4" DOT without a bushing reducer. They make a fitting that will but it isn't common stock. It makes more sense to use a 3/8" inlet and outlet than using extra reducer bushings.

My m322 trailer uses the same type of brake relay module that our trucks use. When the pedal is released the air to the modules is dropped and it is vented off using the relief valve. Same thing as if you pump your brakes while you are holding it to the floor. That extra "pop" of air is on the relief valve. Same thing.

 

[74M35A2]

OK, got it. To do it same as all the road tractors, you use what is called a "double check valve". The key point of this is as stated in its literature, it always allows pressure to drain in reverse flow, from either source used (not simultaneously). So, I really would not call it a check valve, I would more-so call it a "priority valve" or "shuttle valve", as there is no one-way check valve flow function to it. All it does, is shuttle the valve to use the higher side pressure. Once done, it allows that pressure to drain/vent/bleed off from the same source, while keeping the other blocked. The treadle valve and hand brake valve both have venting provisions built into them. I think using a single inline flow check-valve on one or both lines would cause the trailer brakes to not release. BW 280809N is one such part number for a "double check valve" used in hand brake applications in conjunction with treadle valve (foot pedal).

Bendix "Double Check Valve" description, usage applications, and system diagrams:

http://www.google.com/url?sa=t&rct=...umentID=4970&usg=AOvVaw3OfI9Ko15wtuBJ_eoqGutw

Hats off to Simp for doing it, I'm just going to use a different check valve. As always, he gets it done, and my dreams sit on a shelf.

 

[jimbo66348]

This is quite simple. You need a double check valve to feed pressure from both the primary and secondary brake systems to the trolley valve. The purpose of a double check valve, is simple. It allows the side with greater pressure, to pass through. Down line you need another double check valve where you tie into the trailer service line. This let's the control with the greatest pressure to operate the trailer brakes, and keeps the air from backfeeding. A brake light switch should be put on this valve to operate the brake lights. You stated that you want it original. If you plan on using it, all has to be dot approved. It doesn't really matter where you tie in, just that it is correct. You also need a trailer parking brake valve, and a tractor protection valve, in the system.

 

[74M35A2]

There is no such thing as “DOT approved”.

 

[Jbulach]

There is no such thing as “DOT approved”.

What’s you daddy’s name? We might be brothers after all...

 

[simp5782]

What’s you daddy’s name? We might be brothers after all...

His daddy's name is simp

 

[74M35A2]

 

[Castle Bravo]

There is no such thing as “DOT approved”.

I have found that it is difficult to get people to believe this.

 

[jimbo66348]

There is no such thing as “DOT approved”.

There most certainly is. You can't use compression fittings from a plumbing store. They are not dot approved. The same with air line. You can't use 3/8 polypropylene line. You need nylon reinforced dot approved airline. You stand corrected.

 

[Jbulach]

I had some DOT approved popcorn once, but someone told me the NHC250 was better than the 8.3 and I spilled it all...

 

[simp5782]

I had some DOT approved popcorn once, but someone told me the NHC250 was better than the 8.3 and I spilled it all...

Or how the Big cam can drag the ISL down the road.

 

[Castle Bravo]

There most certainly is. You can't use compression fittings from a plumbing store. They are not dot approved. The same with air line. You can't use 3/8 polypropylene line. You need nylon reinforced dot approved airline. You stand corrected.

Here is my take on DOT Approved -

https://www.steelsoldiers.com/showt...eel-pin-size&p=1947722&viewfull=1#post1947722

 

[jimbo66348]

Weather or not you people agree with me, doesn't matter. Any part of any vehicles safety systems, have to be dot approved. Look at any taillight lense, or headlight lense. They ALL have dot stamped on them. Get caught in a dot check, and they find non dot parts, your getting red tagged, and heavily fined. It's your choice to use them, but to say they don't exist, is foolish at best.

 

[simp5782]

Weather or not you people agree with me, doesn't matter. Any part of any vehicles safety systems, have to be dot approved. Look at any taillight lense, or headlight lense. They ALL have dot stamped on them. Get caught in a dot check, and they find non dot parts, your getting red tagged, and heavily fined. It's your choice to use them, but to say they don't exist, is foolish at best.

Do you have a A1 or A2 truck?

If you have combat wheels on your 5 ton the they are not DOT approved so you better park it.

 

[74M35A2]

I’ll just leave this here....

http://www.bikersrights.com/nhtsa/notapproved.html

 

[Castle Bravo]

Weather or not you people agree with me, doesn't matter. Any part of any vehicles safety systems, have to be dot approved. Look at any taillight lense, or headlight lense. They ALL have dot stamped on them. Get caught in a dot check, and they find non dot parts, your getting red tagged, and heavily fined. It's your choice to use them, but to say they don't exist, is foolish at best.

I'm not saying parts don't have DOT stamped on them don't exist - certainly they do, but it is because the FMVSS requires that that they do and not because they are some how DOT approved. Either 74M35A2's link or mine provides several examples of the NHTSA's own claims about DOT approval.

Nor am I claiming that the parts stamped DOT are not the parts all of us should be using. If the DOT stamp is also indicating FMVSS/DOT compliance, that's probably a good thing.

My point is that there is no such thing as DOT approved.

 

[snowtrac nome]

I'm not saying parts don't have DOT stamped on them don't exist - certainly they do, but it is because the FMVSS requires that that they do and not because they are some how DOT approved. Either 74M35A2's link or mine provides several examples of the NHTSA's own claims about DOT approval.

Nor am I claiming that the parts stamped DOT are not the parts all of us should be using. If the DOT stamp is also indicating FMVSS/DOT compliance, that's probably a good thing.

My point is that there is no such thing as DOT approved.

the dot stamp just says that the part complies with the standard. the dot stamp is a must for air brake systems because every thing is engineered around those dimension's and preformance. you can successfully use a crimped 3500 psi hydraulic hose, but there is no guarantee that you will get the required flow through that hose and this could cause one brake to apply faster or slower than another. Same goes for changing out a straight fitting for a 90 because you think it looks cleaner with out such a big loop. There is a lot of engineering that goes into an airbrake system because the hoses hold nothing in them when not in use like hydraulic brakes and Changes in the design will change performance.