Pick up 504 cardan problem

Hello everyone, I am having problems with the rear stress of the cardan of my truck, weld it and cut every two or three months, the cardan new step the same. The truck is used in a normal way, it is not loaded, it normally walks by route to no more than 100 km, I always handle it, that is, I don't know what will be happening if someone expert can help me, I will appreciate it very much !!

Hello friend, that is not a soldier, you have to change the cardan and the Manguito of coupling because it takes play in the stretch marks and you will always have those problems, greetings.

Thank you Jal for your answer, we already tried new cardan. Now they are seeing if the gun is crooked or something. I will also take into account your advice.