Mazda 616 rear koni shocks

[kv77]

I have a 1975 Mazda 616 (capella 1600) that had cut springs and koni shocks when i got it. I now have bought a parts car that has original springs and koni\'s and replaced these on my car. Front works okay now, the back is giving me troubles.

When i swapped the rear shocks with the new koni\'s and original springs, it worked okay for a few kms, but after that the left side seized. I couldn\'t push the car down, but when I jacked up the car the strut would decompress, so it\'s not totally seized.
I then took the old Koni (with the cut spring) and put the new spring on and put that reassembled strut under the car. Again, it worked fine for a moment, but then exactly the same problem occured! Again no more movement in the strut, except when i jack up the car.

The trailing arms and panhard bar are okay. I pulled the shocks from the car again and the left one is broken . You can\'t compress it anymore with the spring removed. I now have two f*cked shocks in a week time.

I have a last spare shock ready to install but before I do : is there anything that can go wrong when mounting the shocks? Does the position (rotation) of the strut top make any difference at all? Can the spring be faulty? It appears to be straight. The manual says that you need to install the strut with the protection plate towords the front of the car. The Koni\'s don\'t have a protection plate...

Are red Koni\'s for Mazda Rx2 (or 616) adjustable?

Thanks
Kenny