Hello People.... I am new to this forum just joined it a minute ago..!
I am looking for some help here is the problem:

I have a trek 4300d, I was trying to clean the bike after a muddy ride so I removed the rear wheel from the frame.

I was then not able to get the wheel back in its place, so I took the bike to the station and got the wheel fixed.

I got the bike back in my car by keeping it on the roof of the car.

Now the moment I got the bike off the roof and on the ground the real brake got jammed and was not moving freely.

I went to the station again and they fixed it, same thing happed when I took the bike of the roof this time.

I just dont understand what is wrong, does this mean a bike with hydraulic disc brakes cannot be kept horizontal..!??!?!

PLEASE PLEASE HELP ME..!!