Brakes pulling

2017 Freightliner Cascadia. Roughly 16,000 miles on truck. Problem has been exhibiting since I got in the truck with roughly 2000 miles.

The brakes have been pulling hard to the right, but only intermittently and occasionally. Seems like some days it is happening a lot. Some days it doesn't seem to happen at all. Even when it's happening it isn't happening with every brake application. First time I noticed it happening a lot it was raining really hard, but I had good traction, since then I've been in all kinds of weather conditions and there seems to be no rhyme or reason to when or why this is happening.

Two dealerships have looked at it. The first one diagnosed it as a faulty quick release valve. I've since been told that that doesn't fit the symptoms (pulls on brake application not on release) and that there is only one valve for both of the front brakes. The second one checked brake adjustment, brake thickness, tire pressure, and then called it quits because they don't have a CDL driver available to test drive the truck outside of their lot. Clearly none of those issues would cause the problem I'm having, and they tell me they won't do any tear down of the brakes until they've test driven it. I leave tomorrow to take a load up north and they won't make any more progress on this vehicle before then.

Anyone have any ideas on what would cause this intermittent problem? On juice brakes I'd be looking at greasing the slides in the calipers, but I'm not as familiar with the maintenance/repair of S-cam air brakes. I'm assuming there is something in there that can be greased or should be checked for manufacturing defects to see if something might be hanging up and stopping the brakes from applying properly sometimes?

 

No, sorry, drum brakes. No calipers, I probably made that confusing by mentioning it.

 

Yes. And it is generally pretty hard, it's not a gentle drifting to the right, I'm talking about you better have a good grip on the wheel kind of thing.