Don't set your brakes!!!

If the scale isn't perfectly level, you're not getting an accurate weight either. Usually, I pull on the scale, put it in neutral and wait till the truck stops moving.

 

I'd say a lot depends on your typical trailers. If they dump the airbags when you remove the air from the trailer (as many do today), then I'm inclined to say "no, set the tractor brake only and keep the trailer at normal ride height"

And furthermore, if your truck will easily roll one direction or the other, as you try and axle scale, (such as on some private scales they use to weigh short raw materials truck's gross) then you're individual weights are not going to be all that accurate and potentially off considerably if any incline hang-off is considerable

 

I've seen as much as 700 lbs come back onto the drives [from a trailer that dumps air bags upon removing trailer supply] when the trailer bags are reinflated and the trailer level comes back up that 2-3 inches or so.

If the trailer doesn't automatically dump the bags, it's probably not so much an issue pulling the red button but I still don't see an issue setting tractor brakes and letting the trailer remain free to roll.

 

Scale is suppose to be level. Tanker drivers will get bad reading. I never set the brakes unless it will roll

 

Who has maxi-brakes on the steer axle?

Regardless, I never set the brakes either.

 

When I was a driver trainer for Matlack I got a; lot of strange looks from experienced drivers who were new to tankers when I told them to not set the brakes on the scale. they would walk away watching the whole rig roll back n forth about 5 - 6 inches. Setting the brakes makes the moving liquid influence the scale.

One stop in Tenafly, NJ had a huge sign...chock your truck, the scale is not level...

Another place had a short scale and made us drop the trailer. We would wait 5 - 10 minutes for the scale to stop moving.

 

I never set the trailer brakes on the scale, only the tractor brakes. Some trailers when you set the brakes will also dump the suspension changing the load dynamics.

 

The tractors drives and steers being on different platforms wouldn't matter...set the tractor brake and only the brakes on the drives are applied. No parking brake on steer axles, at least not in any truck I've driven.
The platforms wouldn't bind.

Some scales are a single platform. Set whatever brakes you want. Won't matter there lol

Spread axles - if both axles aren't on the same platform never set your trailer brake. Apparently some van drivers do that...