How to control trailer air-brakes?

[zout]

Well - your welcome.

Basically on elec brakes all your doing is hooking a controller of of voltage into a proportioning system - you control the trailer voltage supplied by dialing it in from the main dash controller. This controls nothing to the lead vehicle.

Not so with air sytems. I gave the diagram only as basics - as said - they are many different systems and designs @Wedge brakes lot less moving components and therefore a more instant direct braking system but a PIA for some to work on.

In air systems there is no interchange of components from the main designs as these have all been calibrated and well thought out.

Braking with the foot treadle valve with trailer hooked on air system - it is a more regulated pressure thoughout the entire system.
Braking with only the hand trailer valve - you need to watch the gauge and nearly at 30# pressure your locking up the trailer brakes. Grab a handfull of trailer valve and hold on to your pants.

Hope this helps

 

[73m819]

Well if you knew me or knew what you were talking about then Im might care what you think. Ive known everything thats listed on this thread (stupid answers like explaining to me why a empty trailer locks its wheels or what trailer only braking is for) I just dont bother telling them because again like you they dont know me and unlike you are trying to be helpful... I was asking specifics on a truck that I dont know.
If it will make you feel better then delete the thread!

If you KNEW everything that was posted in this thread, WHY in the he11 did you ask your question in the first place ????

 

[racing4funn]

If you KNEW everything that was posted in this thread, WHY in the he11 did you ask your question in the first place ????

I asked something that still has not been answered.. Im assuming because it does not exist or it isnt relevant. trying to explain my question and what I know or dont know is exhausting.. I quit

 

[212sparky]

I have a tractor that has the separate trailer control to the right of the steering wheel but that’s for braking the trailer separate. How would I adjust the trailer to truck ratio? Meaning I need more trailer to truck or the other way? What if the trailer’s air supply line attached behind the cab for a 5[SUP]th[/SUP] wheel setup or what if its at the rear on a panicle. Are both of those locations controllable?

It has been answered, the Johnny bar is for checking brakes. If you want to fine tune the brakes, tweak the valves or use your foot.

 

[racing4funn]

Let me help you, Everyone missed this. His only experience is with electric brakes, 99% of electric brake controllers operate off of time. The longer the pedal is held the more current that is applied to the electric brakes at the wheel. When empty you turn the voltage down so the tires don't slide. That is his way of thinking. Air brakes on the other hand are controlled by the air pressure applied by the foot valve. The harder you push the more pressure that is put on the relay valve the more air pressure that is applied from the air reservoir tank the air chambers. Its regulated with your foot and your natural ability to do so. Some may say "well if I hook my 105 trailer to may deuce it will slide the brakes empty" and they would be correct because it is a air over hydraulic system and functions just like the electric brake. The longer you hold the pedal in the deuce the more air that is applied to the master cylinder, the harder the brakes are applied. Closing the valve on the trail air some will help that by limiting the air flow. Clear as mud

yeap.. just trying to understand from a mechanic or engineer point. Since I service everything I own, air brakes are new to me.

I hope this tread dies a horrible death. Similar to the way I orchestrated it. Someone delete this and put it out of its misery.. Im out of here.

 

[Floridianson]

There is another use for the trailer brake. I sometimes back allmost up to the trailer hook up the air lines, air up the trailer and put the trolly brake on then back up under the trailer. This is so the trailer does not shift.

 

[NDT]

The longer you hold the pedal in the deuce the more air that is applied to the master cylinder, the harder the brakes are applied.

This statement is incorrect. If this were the case, if you lightly applied brakes far away from a stop, by the time you got to the light, you would be in panic stop all wheels locked. It should say, the further down you press the pedal, the more air pressure is applied . . .

 

[5tonman1971]

Your hand brake is not adjustable. The only adjustment is simply less pressure on your brake pedal. Or if using the hand brake pull it down less.

Sorry so many people let thier prides take over and just start spewing irrelevant information. A lot of people on here forget that at one point they were in your shoes. No one comes outta the womb knowing everything, even tho a few people think they do. A CDL is helpful but that does not make you a super trucker. I know a few guys that have a cdl but that Dosent mean I'm gunna let them behind the wheel. Cdl is just a piece of paper and a bunch of fees and testing.

But like a lot have said it's not for daily use, I've only used it took hook to trailers and test brakes. There was one time I was running loaded and had to use it to help apply extra braking power to stop quickly when a Sunday driver decided to stop in the middle of the road around a fast curve to take a picture of fricken Halloween lights.... I was very mad.

 

[zebedee]

I guess 'racing4funn' has left the building.... But he kept saying that the orginal question hadn't been answered (I count 3 questions):

I have a tractor [m931A2] that has the separate trailer control to the right of the steering wheel but that’s for braking the trailer separate. How would I adjust the trailer to truck ratio?

First statement "for braking the trailer" - sort of correct in that all it controls IS the trailer... WHEN TO USE is the point others were making.
Truck / trailer ratio - only adjustable (if you really need to) can be achieved, as said, by the valve that supplied the 'hosetenna'(pogostick etc).

Meaning I need more trailer to truck or the other way?

Shouldn't need to do this if everything is in spec - brakes on all of combination and the use of trailer being within the trucks capabilities. Pulling too heavy a trailer for the truck gets you into a place you don't want to go. I guess you could drill a small hole in a quarter and put it in the trailer glad hand - that would adjust things a tad!!!

What if the trailer’s air supply line attached behind the cab for a 5[SUP]th[/SUP] wheel setup or what if its at the rear on a panicle [pintle?]. Are both of those locations controllable?

Both air line connections(glad hands) are operated from the same system, hand 'trolley valve' and foot treadle valve (pedal) but are not adjustable other than answers above.


Not totally sure how this thread fell off the rails and got so many people bent out of shape - if the answer received doesn't answer the question posed - why not re ask the question in another, more consice way? After all, "...one of the signs of insanity is repeating the same thing expecting a different result." Einstein I believe said that.

NB. If airbrakes are new to you (the OP) then can we assume that you don't have a CDL? (rhetorical question at this point I feel)