Adjusting wheels on a 1970s sliding alumimium door

[OldKettle]

Hi,
I am trying to adjust the wheels on a sliding aluminium patio door (circa 1970s).

The door is misaligned so that, on the lock side, the bottom slides into place, but the top is about half an inch out.

I've located the adjustment screws. The one nearest the lock side turns freely, but the one on the opposite side will one do, perhaps, one turn.

Before I look at this further, I wondered if anybody could advise whether this might be by design, rather than just seized up.

 

[Gazman16]

Probably seized or broken. Replacements are cheap but can be a little tricky to find the exact ones and to fit as you generally need to completely dismantle the door.

It should be pretty easy to lift the door out and take a good look

 

[OldKettle]

Thanks. Door was almost impossible to close, so I took it off, cleaned everything and then put it back out. Hope I didn't damage the wheels when getting it back on. Had underestimated how heavy it would be