I've got a dumb question

[fattboy123456]

Ok so I have only drove this truck now a hand full of times and i still cant figure out what this is....I feel dumb as **** right now LOL

 

[Rmtaunton]

Johnson bar or trolly valve , it is used to apply or test brakes on trailer with air brakes , you really should never use it while driving . Unless you really know what your doing

 

[porkysplace]

It is for trailer brakes . You really need to read the operators manual for your safety and everyone else on the road.
TM9-2320-272-10.pdf
TM9-2320-272-10 Operations manual for the M939 series trucks. Sept 2004

 

[NovacaineFix]

...

 

[Floridianson]

I like to hook up the air lines just as the tractor reaches the trailer and apply the trolly so when I back into the trailer to make the hook up to the pin the brakes are applied and it does not roll back.

 

[fattboy123456]

Thanks for that PDF much to read

So im assuming that lever only controls the TRAILER brakes....? Not the Trucks as well

I have drove it while adjusting that lever with seeing no change

and what position should it be in for Non towing setting (since It the moment i dont own a trailer with air brakes)

THank you!

 

[M35A2-AZ]

Thanks for that PDF much to read

So im assuming that lever only controls the TRAILER brakes....? Not the Trucks as well

I have drove it while adjusting that lever with seeing no change

and what position should it be in for Non towing setting (since It the moment i dont own a trailer with air brakes)

THank you!

It need to be up for normal driving and only used for applying trailer brakes. Like when your hooking up to a trailer to test if it is locked in the 5th wheel.

 

[98G]

Thanks for that PDF much to read

So im assuming that lever only controls the TRAILER brakes....? Not the Trucks as well

I have drove it while adjusting that lever with seeing no change

and what position should it be in for Non towing setting (since It the moment i dont own a trailer with air brakes)

THank you!

Randomly moving levers of unknown function while going down the road is not a recommended practice. Badness can and will ensue.

you're going to have a bunch of people tell you you need a class A CDL. I won't go quite that far, but you most certainly need the knowledge that would be required to get the class A. I strongly recommend that you read California's class A instruction manual as well as the TM for the truck.

These things don't behave like an oversized pickup truck. The next random control you push might disable your emergency brakes, or might dump all the air from your springbrakes and lock them up, kill your engine, and roll you over.... and while I am in full agreement that your life is yours to risk as you see fit, you may kill a bunch of other people as well....

And I'm not usually the one that is the voice of caution....

 

[fattboy123456]

Thank you for you concern should have posted I have drove many larger class C Trucks with air brakes Yeah I wont be wasting time or money with class B or A licence I did my research and got it registered as historic $80 a year reg and from what i have read and talked to people (dmv and hwy patrol) they dont care when it come to military trucks im guessing being patriotic and such...I have always been the kind of Person to bend a few rules here and there...

thank you all again

 

[98G]

I have drove it while adjusting that lever with seeing no change


u!

Let me change one variable in what you did, and illustrate what could have happened...

postulate for the moment that you had an empty trailer behind you when you were "adjusting that lever".

You pull the lever, trailer brakes lock, trailer goes sideways and totals the little econobox next to you, then trailer flips over into oncoming traffic and claims a couple of more victims. All this happens before you even realize the brakes locked.....

 

[dmetalmiki]

Let me change one variable in what you did, and illustrate what could have happened...

postulate for the moment that you had an empty trailer behind you when you were "adjusting that lever".

You pull the lever, trailer brakes lock, trailer goes sideways and totals the little econobox next to you, then trailer flips over into oncoming traffic and claims a couple of more victims. All this happens before you even realize the brakes locked.....

Too scary to even contemplate. Grab a T.M. appropriate to your truck. (not for good reason that some refer to that as the "dead man handle". Now if it had been the "ejection seat lever"!/?

 

[steelandcanvas]

opcorn:

 

[wreckerman893]

A quick lesson in military trailer brakes.

The older trailers with air over hydraulic brakes do not lock up when the air is drained off of them. If they are on uneven ground the ones with dolly wheels on the landing gear will wander downhill if they are not properly chocked. This is not amusing to Motor Sergeants, Battalion Motor Officers and other people that have to investigate vehicular accidents.

If you attempt to couple up to one without hooking up the airlines and/or chocking the wheels it will attempt to roll away from you.

That is why a lot of Motor Pool fences have dents in them.

If you read the Operators manual for any military tractor it will give you step by step instructions for coupling/uncoupling trailers.

Basically you back up until the 5th wheel is almost to the kingpin of the trailer (you should have adjusted the height of the trailer with the dolly crank).

You lock the brakes on the tractor (if it is a newer one with straight air brakes) or set the emergency brake if it has air over hydraulic brakes.

You get out and climb up on the deck of the tractor and hook up the airlines.

You get back in the tractor, release the brakes and pull the Hand valve/Johnny Bar/Trolley Valve to apply the trailer brakes.

You then back up until you hear the jaws of the 5th wheel lock around the Kingpin.

You put the truck in low gear and pull forward with the Hand valve still applied to make sure the fifth wheel is locked (it is very embarrassing to have a trailer fall off the back of a tractor going down the road).

Once you are sure the 5th wheel is locked you hook up the electrical cable (called an IV Cable) and dolly up the landing gear.

This Public Service Announcement brought to you by a former Motor Transport Operator/Master Driver/Drivers License Test NCOIC.

 

[73m819]

Let me change one variable in what you did, and illustrate what could have happened...

postulate for the moment that you had an empty trailer behind you when you were "adjusting that lever".

You pull the lever, trailer brakes lock, trailer goes sideways and totals the little econobox next to you, then trailer flips over into oncoming traffic and claims a couple of more victims. All this happens before you even realize the brakes locked.....

This IS WHY you SHOULD read the -10 BEFORE driving the truck, not after something happens

 

[fattboy123456]

Two pages deep on asking what a lever does LOL
Thanks for all the answers and over kill answers

 

[steelandcanvas]

No overkill answers, just answers and suggestions.