olroadbeech

Happy Verified UPSer
How do you test the service brakes on a dolly? How about the rear box? Once your hooked and use trolley bar how do you know it's not just your front box holding you stopped
if there is no air to dolly or rear box , they will not move. they need the air to release brakes. that is why when you do your walkaround you turn on the air valves on the back box to see that air is going thru the system. if not , then you did not turn air valves on from back of front trailer. Or you did not hook up air lines right.

Just like Trick said. This is part of pre-trip. When in doubt ask another feeder driver to walk you through it. Better safe......
 

olroadbeech

Happy Verified UPSer
When the pin won’t release, just get back in the tractor, put it in reverse, and bang it backwards enough to jerk the trailer. Works every time.

This is one of about 100 things an on road supe won't tell you because most of them don't know. It comes from experience.
 

Indecisi0n

Well-Known Member
Are you saying if the emergency air (red) is turned on but the service air (blue) is not the trailers won't "freewheel"?
So as I understand it , if the blue pops off then you will only have the tractor brakes for both the tractor and the trailer correct? I know if the red pops off it will lock up and make you :censored2: your pants.
 

Rick Ross

I'm into distribution!!
So as I understand it , if the blue pops off then you will only have the tractor brakes for both the tractor and the trailer correct? I know if the red pops off it will lock up and make you :censored2: your pants.

Some shifters only hook up the red airline, no blue or light cord. The 10 seconds they save can be put to better use playing on their phones :)
 

Johney

Pineapple King
So as I understand it , if the blue pops off then you will only have the tractor brakes for both the tractor and the trailer correct? I know if the red pops off it will lock up and make you :censored2: your pants.
Yes that is correct and when that happens you will know as soon as you come to the first traffic light if you're pulling a full load.
 

Indecisi0n

Well-Known Member
Or you could put the red on the blue and the blue on the red then call the mechanic and tell him they brakes are locked up and look like an idiot when he shows up.
 

trickpony1

Well-Known Member
Yes that is correct and when that happens you will know as soon as you come to the first traffic light if you're pulling a full load.

This is why you're supposed to tap your brakes several times before the actual stop because:
-it flashes your brake lights warning those behind you and;
-most important...it tests your brakes to a slight degree.

Methods....some of them make sense.
Crazy, I know.
 

Hadjabear

Well-Known Member
if there is no air to dolly or rear box , they will not move. they need the air to release brakes. that is why when you do your walkaround you turn on the air valves on the back box to see that air is going thru the system. if not , then you did not turn air valves on from back of front trailer. Or you did not hook up air lines right.

Just like Trick said. This is part of pre-trip. When in doubt ask another feeder driver to walk you through it. Better safe......

But how do you know that the service brakes on the dolly and rear box are 100%? If I'm building a set I can tug test the front box before hooking up, if the wheels drag with the trolley bar down I know that the service brakes are working 100‰. Once I'm built doing the same thing for the whole set how do I know the dolly and rear box have 100% brake strength
 

trickpony1

Well-Known Member
how do I know the dolly and rear box have 100% brake strength

You probably never will.
You could take each trailer for a ride in the yard and then apply heavy brakes and look (in mirrors) for:
-one set of duals still turning and the other skidding or;
-pulling to one side.

The dolly can't be tested in this manner.

OR you can use common sense and your methods and give yourself plenty around ahead to slow/stop.
 

Indecisi0n

Well-Known Member
But how do you know that the service brakes on the dolly and rear box are 100%? If I'm building a set I can tug test the front box before hooking up, if the wheels drag with the trolley bar down I know that the service brakes are working 100‰. Once I'm built doing the same thing for the whole set how do I know the dolly and rear box have 100% brake strength
If your tug testing when hooking up and moving the kit then you know the brakes work. Then when you check to make sure air is escaping from both the service side and emergency side out of the kite there is no reason why the brakes shouldn't be working on the kite. We were never taught to tug or test the brakes on the dolly.

I assume you could charge the front box and dolly together then disconnect the dolly air lines (dolly remains charged) then release the brakes on the trailer and tug teat the dolly.
Ain't nobody got time for all that.
 

trickpony1

Well-Known Member
If your tug testing when hooking up and moving the kit then you know the brakes work

You know the spring brakes work but not the service brakes.
There's a reason they train you to:
-release tractor brake, pull hand lever down and tug on trailers (assuring your tractor is hooked to trailer)
 

Indecisi0n

Well-Known Member
You know the spring brakes work but not the service brakes.
There's a reason they train you to:
-release tractor brake, pull hand lever down and tug on trailers (assuring your tractor is hooked to trailer)
Honestly , they never once told us to tug test like that but it makes total sense.
 

trickpony1

Well-Known Member
I know someone who attempted a "carrier landing" into a truck stop but there was a slight problem...

He forgot to turn on the service air to his back trailer.
Luckily, he realized the problem and diverted to run off onto the shoulder.
He said the brakes on the front trailer were still stinking when he came out from the store.
 
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