Brakes delay releasing when supply air

When you pull your dash air valve handles out your brakes are being set.

Pushing said brake valves in releases your brakes.

Usually, when there is a delay in releasing the brakes, it means the brake springs need more time for the air to work. A common occurrence, especially in older trailers.

My tractor brakes don't always release quickly. It's just taking time for enough air pressure to build enough to compress the brake springs.

Not a big deal.

 

Sounds like the 4 way valve is sticking.

 

Some trailers have big air tanks and small air lines to feed them. Which is has its positives if the trailer has very few leaks and is pulled everyday. It maybe that the trailers you’ve been hooking to just take that long to air up and release the brakes.

The other thing, you said that your not in you normal truck. It could be that the tractor protection valve is hanging up on this different truck and not letting full air back to the trailer initially.

 

Look at the inside of the drums for a big lip indicating that the drum inner diameter is wore out, making the ID too large. This big drum coupled with thin shoes can let the S cam try to "cam over" and jam up with a brake dragging even though your chamber has released the pushrod. Last night i had the back left corner on the trailer catch fire from this without ever feeling a thing. Dont keep changing shoes without doing the drums too.