Sliding door catch problems

[Huyrob]

1971 lhd. I’ve started to experience problems with the rear catch of the door not engaging without slamming. I have always closed it by right hand on handle to slide and left hand pushing on rear of door to help. Never had a problem. Now I have to really push and slam. I haven’t tried yet but I reckon it would be really difficult to close from the inside. The mechanism looks ok and it is all lubed up. any suggestions please ?
The door slides to open smoothly, what I have just noticed is when it is at the point where the rear section pulls in …if I lift the bottom left of the door I hear a definite “ click “ in the sliding block where the chrome arm enters the block, It then hits some sort of resistance which requires a tug to clear it, once cleared the door slides to and fro with no problem

 

[sparkywig]

Have you checked that the rear of the door hasn't dropped? The roller splits and the nylon block wears, and the U hinge bronze bushes may need replacing as well.