Unlocking a fifth wheel that has accidentally tripped shut......

They crank landing gear until it touches the ground and then throw in a few extra cranks "because one time in band camp..." or their first company said the FMCSA required it, or who knows.

 

Far more variation in trailer drop height is due to driver preference and ground at different doors. You have angled doors instead of warehouse being built dock-high above ground, they dig out a ramp below ground level. Or trailer is being dropped in gravel yard with one concrete strip where landing gear is supposed to be placed. Inevitable, the ground in front of concrete strip is dug out. Then that trailer is put in a door by yard truck and dropped somewhere else with asphalt. When road truck goes to hook up to that trailer the trailer is too high or too low.

EVERY NEW DRIVER ON OUR ACCOUNT DROPS TOO HIGH. It doesn't matter if they drove 30 years in Chicago, coast-to-coast, all 48 states. It doesn't matter if they got their CDL last week in a grocery store. Once they are shown the proper way, and more importantly experience getting a too high trailer from the other new guy, then they see the light. At first, they all say the same thing. "I don't leave my trailers too high, I just touch the ground and put in a few extra turns for good luck." Yep, driver. You are the guy dropping too high. "Oh no, not me. I think the yard truck driver comes over when nobody is looking and raises my dropped trailer and cranks the landing gear too tall to make me look bad." No, driver the yard truck drivers are moving 150 trailers in 8 hours, they don't have time or the cartilage in their knees for climbing in/out of their truck one unnecessary time. You know what happens if you don't stop this high trailer stuff, you will start getting trailers dropped too low until you get tired of that.

If you do it right you will feel resistance when backing under the trailer, that's the weight being taken by the tractor. If you are doing it wrong, you won't hear a sound when you pull away from the trailer. You might be able to hear the next driver cursing you and your ugly momma for dropping the trailer too high, but I doubt it.

 

Absolutely, if you are backing under a trailer you should be lifting the front several inches.

 

In over 20 years i have never used one.

Op, get a pipe and 3 pound sledge. Give it a whack at a rear angle to unbind it the carefully push the jaw back with the pipe. Position yourself to be out of striking angle in case it snaps back while pushing the jaw with the pipe.

 

Screw that. You have any idea how much work it is to tear the floor up to replace the king pin plate? A half an inch is enough to make sure you get a good lock, but not so much it puts extra strain on the front edge of the plate.

 

I'm sorry but I don't buy that. The pressure is on the 5th wheel. All you are doing is sliding the strike plate up the 5th wheel. I'm not a rookie, I know better. Edited to add this is why the 5th wheel pivots.

 

Ya I know you're a guy fifth wheel puller are for sissies,lol.Alot easier then your method in my opinion.

 

There is never ever, any reason to allow the trailer to touch the tractor frame.

 

Equal pressure is applied to the kingpin plate. A solid piece of steel. If you got a grossed out load that's how much force being applied at the very edge of that plate? I'm to lay to do the math but it's a crap load. Not to mention your fifth wheel rides on nylon bushings. There is a reason every heavy haul truck has ramps welded rear of the fifth wheel.

Keep in mind, you said several inches. A couole us 2, A few is 3 to 4, how many inches is several?

 

I can think of one. To use the air suspension to raise the trailer enough to get under it cause the last jackwad dropped it several inches low. Even brand new landing gear is a ##### to lift a fully loaded trailer up.

In case its not clear, i mean dumping the air so the truck frame goes under the trailer without actually touching it. Blowing the suspension up to raise the trailer. Crank the landing gear down and repeat with a 2x4 on the truck frame. Add more blocks as needed.

I've had to do this often moving customer trailers off of job sites. Sitting 3 months on soft soil makes those easy power only loads a bit more time consuming.

But in normal situations, i agree, no reason and anyone that does so obviously doesn't care about his equipment.