Feeders - Proper coupling/uncoupling procedure?

[Coldworld]

What is exactly happening when you hook to a trailer and hook the lines up then go back to cab and push red button in and pull down on the hand value... There's that sound that it makes on the trailer ... Is that the break chambers???

 

[Coldworld]

I've found if that spring is broke, or out of place, you will know if you give the handle a good tug. If everything is OK, it won't pop out. If it DOES pop out, usually that spring is above (if I remember right) that small round pin at the base of the slot. I know, I know, this should have pics, but when you pre-trip after you've snagged the back box, and tug the dolly handle and it slides easily out of the hole, that 6 or 8 inch bar below the handle is above that pin. If you have a screwdriver, you can flip that bar below the pin and the handle will stay put. This all looks confusing in print, I know, but what we need to remember, is if, after you're hooked, you tug on the dolly handle, and it pops out of the slot, you've got a problem, and most likely, it's just that little bar above the pin, instead of below it. Always tug, and if it comes out of the groove, head to the shop.

Bottom line, if you can jerk that dolly handle out of the slot without pulling it UP, it wouldn't take much, say a stray air line, to pull that handle towards the driver's side. If that happens, you better be looking in your mirrors, because you'll need to tell the tow company where to pick up your back box.

I'll see if I can take a clear picture of that 6 inch bar and the little pin it hooks below tonight and post tomorrow. And, of course, I'll make sure I'm on my meal while I do it. HAHAHA.

I also learned that if you pull the pin then put it back in again without even moving the rig at all that the box will drop...and yes that is a sound you will never forget ... Luckily it was at night with nobody around...

 

[olroadbeech]

Have you known anyone who has dropped the back trailer on a freeway??? If you were going 55 mph and the back box got unhooked would the trailer flip over or are they designed to stay upright ??

yes, we had a guy drop a back box going about 60 near Richmond.CA.( it was probably high pinned ) it was around 4 oclock in the morning. he said it just skidded straight down the road on the landing legs. he had to roll down the legs and backed the dolly up and reconnected before the CHP arrived.

he had a nickname after that..."dropbox"

 

[retiredTxfeeder]

Have you known anyone who has dropped the back trailer on a freeway??? If you were going 55 mph and the back box got unhooked would the trailer flip over or are they designed to stay upright ??

I've seen it happen a couple of times (not by me) In each case, the trailer basically just went down on it's landing gear and slid straight as an arrow.

 

[retiredTxfeeder]

I also learned that if you pull the pin then put it back in again without even moving the rig at all that the box will drop...and yes that is a sound you will never forget ... Luckily it was at night with nobody around...

I always just pulled up about a foot, keeping the 5th wheel under the trailer apron, then just back it back up and re-latch it.

 

[Coldworld]

Never buy a puller in a truck stop. Brown makes billions, and I'll pester the shop before I ever leave the yard without a pin puller. No way does my wallet open up for this company.

yes, we had a guy drop a back box going about 60 near Richmond.CA.( it was probably high pinned ) it was around 4 oclock in the morning. he said it just skidded straight down the road on the landing legs. he had to roll down the legs and backed the dolly up and reconnected before the CHP arrived.

he had a nickname after that..."dropbox"

if it was high pinned I'm surprised it didn't drop much sooner??

 

[retiredTxfeeder]

if it was high pinned I'm surprised it didn't drop much sooner??

Sometimes dollie latches fail. Doesn't happen often, but it does happen. Not necessarily a high hook. It would be hard to get feeder management or automotive management to admit it, but ask the mechanics.

 

[Coldworld]

Sometimes dollie latches fail. Doesn't happen often, but it does happen. Not necessarily a high hook. It would be hard to get feeder management or automotive management to admit it, but ask the mechanics.

So even after a test tug and visually checking the couple the trailer "could" still detach???

 

[Dracula]

I've never known it to happen, but, after hooking the back box, if that pin is in the slot, and can be easily pulled out of the slot without lifting up on the handle, I won't take it out on the road. Not s chance.

That dolly handle is connected to the ring that collars the pin that you see when you check around the back of the dolly. So if that handle, somehow, slides to the driver's side, then that means that safety collar isn't around the pin. And that means the only thing holding your box to the dolly is momentum and your cords. That's a bad place to be, however unlikely it might happen.

 

[Johney]

yes, we had a guy drop a back box going about 60 near Richmond.CA.( it was probably high pinned ) it was around 4 oclock in the morning. he said it just skidded straight down the road on the landing legs. he had to roll down the legs and backed the dolly up and reconnected before the CHP arrived.

he had a nickname after that..."dropbox"

And how did he get the name "dropbox"?The CHP didn't show up? Because he told everyone about it? There is no way in hell a feeder guy drops a box on the highway and gets away with it then talks about it. Double

 

[Mugarolla]

So even after a test tug and visually checking the couple the trailer "could" still detach???

Yes it can, if the dolly fails.

They also have problems with the new trailers. The kingpin is moved forward about 6-8 inches to accommodate the change in the front corners of the trailers.

By moving the kingpin forward, the dolly release handle sticks out in front of the rear trailer and UPS has had instances of the air lines to the rear trailer catching the release handle and releasing the latch.

Trailers have been dropped. Mostly at slow speeds turning a tight corner.

 

[olroadbeech]

So even after a test tug and visually checking the couple the trailer "could" still detach???

that 5th wheel locking device is a engineering marvel and if locked correctly hardly ever fails. look at all the roll-over accidents thru history. trucks on their sides or upside down are still coupled to the trailer.

the best advice is to couple the trailers exactly same each time and don't skip procedures. you'll be okay. and if their is ever a doubt in your mind , ask another driver or take it to the shop to have the mechanic inspect.

 

[Dracula]

Yes it can, if the dolly fails.

They also have problems with the new trailers. The kingpin is moved forward about 6-8 inches to accommodate the change in the front corners of the trailers.

By moving the kingpin forward, the dolly release handle sticks out in front of the rear trailer and UPS has had instances of the air lines to the rear trailer catching the release handle and releasing the latch.

Trailers have been dropped. Mostly at slow speeds turning a tight corner.

I avoid this by doing the triple twist with the cords and making sure there is a good three feet from the triple twist from the handle. This can also be done by putting the twist on the front side of the column of the dolly.

 

[Dracula]

that 5th wheel locking device is a engineering marvel and if locked correctly hardly ever fails. look at all the roll-over accidents thru history. trucks on their sides or upside down are still coupled to the trailer.

the best advice is to couple the trailers exactly same each time and don't skip procedures. you'll be okay. and if their is ever a doubt in your mind , ask another driver or take it to the shop to have the mechanic inspect.

Yes, but more times than I've been comfortable, jerking that handle--while it's in the slot--the handle easily comes out of the slot. If that happens, you've got a potential problem. But you are right, if it's secure in the slot, it's going nowhere.

 

[moldsporh]

What is exactly happening when you hook to a trailer and hook the lines up then go back to cab and push red button in and pull down on the hand value... There's that sound that it makes on the trailer ... Is that the break chambers???

When you push on the red handle, this allows air from the tanks to fill the brake chambers on the trailer, this air pressure compresses the parking/emergency brake spring and releases the parking brakes on the trailer. When you pull the red handle, you hear the big escape of air because the spring is setting and forcing the air out of the chamber and red lines.

Now what gets confusing.... with the red handle still pressed in, when you lower the hand valve, you apply the brakes to the trailer and the dolly if attached. This is possible because the parking prake chambers are called "Maxi" chambers which have 2 separate functions and are distinguishable by their large size....steer axle and dolly axle have service brake chambers only and are half the size.

The hand valve does not apply brakes to the tractor, it only allows air to flow through the blue lines behind the cab which is the same air as when you step on the brake pedal...only difference is when you step on the brake pedal, all brake chambers apply brakes, with the hand valve, only trailers and dolly get brakes applied.

The hand valve will only flow air from the blue lines if the red valve is pressed, the red valve is a combination valve. If the red valve is pulled out and you apply the hand valve, no air flows and only the brake lights are applied. The red valve basically "turns on" the hand valve and let's it flow air when pressed in.

So with the trailers hooked up, the hand valve supplies air to the blue lines and is verified by airflow from the rear trailer blue line valve. The red button pressed in supplies air to the emergency side and is verified by opening the red valve at the rear trailer.

You want to ensure air flows from the rear trailer, whether single or as a set.

But again, if you forget to push the red valve in, you won't get air from the hand valve either.

 

[UPS4Life]

I read a couple people say to hook up the lines and then pull the hand valve down, why? When your turn the key off keep the red valve in the yellow valve out and pull the hand valve, go back hook up your lines then turn the valves on the back of the lead.

Another thing I haven't seen yet that I was told years ago by a sr driver was that when building a set make sure your air pressure is above 100psi or your snubber may release when you release the brakes. It's happened to be before I was told about this by the time I'd get to the phones and recheck my couplings one last time before leaving.

 

[olroadbeech]

When you push on the red handle, this allows air from the tanks to fill the brake chambers on the trailer, this air pressure compresses the parking/emergency brake spring and releases the parking brakes on the trailer. When you pull the red handle, you hear the big escape of air because the spring is setting and forcing the air out of the chamber and red lines.

Now what gets confusing.... with the red handle still pressed in, when you lower the hand valve, you apply the brakes to the trailer and the dolly if attached. This is possible because the parking prake chambers are called "Maxi" chambers which have 2 separate functions and are distinguishable by their large size....steer axle and dolly axle have service brake chambers only and are half the size.

The hand valve does not apply brakes to the tractor, it only allows air to flow through the blue lines behind the cab which is the same air as when you step on the brake pedal...only difference is when you step on the brake pedal, all brake chambers apply brakes, with the hand valve, only trailers and dolly get brakes applied.

The hand valve will only flow air from the blue lines if the red valve is pressed, the red valve is a combination valve. If the red valve is pulled out and you apply the hand valve, no air flows and only the brake lights are applied. The red valve basically "turns on" the hand valve and let's it flow air when pressed in.

So with the trailers hooked up, the hand valve supplies air to the blue lines and is verified by airflow from the rear trailer blue line valve. The red button pressed in supplies air to the emergency side and is verified by opening the red valve at the rear trailer.

You want to ensure air flows from the rear trailer, whether single or as a set.

But again, if you forget to push the red valve in, you won't get air from the hand valve either.

that's why on your pretrip you go to the rear trailer and open up the valves to ensure air is going thru the system. BTW excellent post.

 

[olroadbeech]

I read a couple people say to hook up the lines and then pull the hand valve down, why? When your turn the key off keep the red valve in the yellow valve out and pull the hand valve, go back hook up your lines then turn the valves on the back of the lead.

Another thing I haven't seen yet that I was told years ago by a sr driver was that when building a set make sure your air pressure is above 100psi or your snubber may release when you release the brakes. It's happened to be before I was told about this by the time I'd get to the phones and recheck my couplings one last time before leaving.

you'll know if that snubber released, ha ha. going down the road and the trailers seem to be bucking.

 

[Coldworld]

I read a couple people say to hook up the lines and then pull the hand valve down, why? When your turn the key off keep the red valve in the yellow valve out and pull the hand valve, go back hook up your lines then turn the valves on the back of the lead.

Another thing I haven't seen yet that I was told years ago by a sr driver was that when building a set make sure your air pressure is above 100psi or your snubber may release when you release the brakes. It's happened to be before I was told about this by the time I'd get to the phones and recheck my couplings one last time before leaving.

Ive seen drivers leave without even putting the snubber on...

 

[Coldworld]

you'll know if that snubber released, ha ha. going down the road and the trailers seem to be bucking.

Like a bronco