We have jsust had the same problem on our van, even though it is a 16 ft. It was our first trip in the van, we went over to Mudgee and stayed there for 10 days. On the way over the brakes kept locking up at times when we applied them it would alternate between either side, I just kept adjusting the controller down thinking I must have a problem with the controler, not thinking it would be the van as it is only 2 weeks old. Comming back home yesterday all hell broke loose, first the brakes locked up when I just slightly applied them, there was nowhere to stop safely there to check them so we had to drive for about another 2 or 3 kms. I got out to check the wheels etc and could notice a hot brake smell, felt the wheels and the left hand side was extremely/ burning hot to touch, the right hand side was very warm but not burning hot. We sat there for about an hour so they could cool down we were about 10kms out of Merriwa and no phone service, we crept into town and stopped at the NRMA there. We called Jayco in Melbourne and spoke to the service section and after talking about the problems he got me to check the hand break on the van, it only took 3 clicks to be fully on, from this he advised that this had not had any adjustment before hand over from the dealer, and the hand brake had been partially on all the time, and as we went along the van chassis would move and further apply the hand brake, on some occasions we were down to 40 Kms. We got the mechanic at the NRMA to have a look, and when he jacked the van up and went to move the passengers side wheel he could here a grinding/ loose sound, there was one of the springs broken. He tried to remove the wheel and two of the nuts were cross threaded so he couldnt get the wheel off, it was suggested to us from Jayco in Melbourne that since the brakes have got so hot they will need to be completly replaced.
We called RV Assist they were really helpful and would tow the van to Newcastle for us for repairs then it would be our responsibility to get it home, so we ended up going through our own NRMA road side service and got it toed back to the dealer we purchased it from.
Hopefully once these repairs are carried out the next trip will be more enjoyable.
Damien & Mel