Unusual trailer brake issue

The spring brake valve sounds like it could be the problem.If you have pulled the red button but the brakes are not applying you need to remove an air hose from the spring brake side of the chamber and see if has air (it should not) that is the problem.They are simple and inexpensive to change if thats the problem.I just ran into this problem last week on a road call.

 

Yes you would hear the air exhausting from the spring brake valve when pulling the red button if it was operating properly and conditions allowed you to hear it.It is more LIKELY the problem than 3 or 4 brake chambers with broken springs.

 

OR

Your slack adjusters are just out, and all the brakes on the trailer are out of adjustment.
Had that on a trailer awhile back. Went to slide the tandems, and she's just rolling across the lot.

Got 7/16's?

 

Sometimes spraying the sliders down with a water hose and some wheel chocks helps. That does not fix bad brakes.

 

Had exact same problem last winter when temp dropped.

Trolley brakes worked but no brakes on red knob and couldnt adjust tandems.

Roadside came out and tourched the air valves on trailer and it immediately resolved the issue.

I never had the problem come back and still using same truck and trailer.

here is the thread i posted.

http://www.thetruckersreport.com/tr...supply-not-holding.304670/page-2#post-5009863