Thanks Mildman. I will check that link, if needed I will ask you to help in w the pixes.
I did the work today. There was a mass of dried ( on the surface,chewy underneath )up gunk, some glue , in the mating surfaces of the assembly. It looked nasty...all mixed up with dirt that collected there. Got Acetone and with it I got rid of all that crap. It was not easy...but done.
Once cleaned , I used JB weld. The silicone solution sounded attractive but I was a little aprehensive because in case of loosing that lens.....chances are finding another one would had been an incredible endevour. Perhaps overseas because I do not see any cars like this ever more.
Well, mixed the JB weld..... ... that stuff dries up fast!!! and I needed a quite large supply because the lense is large and a one pice deal....so I sweated bullets trying to manage before it went bad. It is very thick stuff...not an easy compound to spread hastily . I think I did it fine. I used 2 C clamps to hold it tight ....looks good. We will see it on the car, the final test .

I will try to post the pixes.

I can see the previous owner did not succeed in his bid to glue the lens to the assmebly because there was a ton of gunk saturating the mating area, making any attempts to glue the parts back together fruitless...the parts could not seat properly....and to leave the lens floating like that detached from the assembly on fifty percent of its mating surface would had resulted in breaking the lens and more water damage to the inside reflectors.

Jaime - I can help you with the pictures too big thing - never glued a tail light but I would use an epoxy resin.

Anyway here's a link that shows easily how to resize images with a free piece of software.
http://datsun1200.com/modules/newbb/viewtopic.php?topic_id=23067&forum=1

Sleeper. what lense did you use silicon on?. I was thinking about silicon, but I do not know if it could hold on tight as an adhesive would. I just would not want to se the lense fall off...sounds good the fact that it can be separated later on and cleaned...but is it hold tight?? I am about to do that work today....I will clean the mating surfaces with acetone free from old glue and posibly silicon residue...and then I will proceed to afix it together.

i took mine apart and cleaned the inside and cleaned up the lens, then re sealed it with SILICONE. works nicely, and can be taken apart if needed.

Tried to load my pixes...but aparently the pixes are way big.....

I will work on it later on and post them.....what a drag.....

I am repairing the tail light assembly. It is not a 1200, but still a Datsun, and this information can help any Datsun owner situation presents.

The tail light assembly was full of dirt and crap. The residents got mad at me and came out in full force trying to deter me from my endevour!!
{ yea, a bunch of spiders, bugs and a centipede }

I submerged the assembly in water...all electrical connectors and wires taken away previously....and the bugs either learnt how to swim or passed away promissing to get even some day!!!

The lens was held in place by a short piece...one of about 8 pins that are plastic welded in place. I had to break that remaining one to separate the lens. I am glad I did, seems like this lens has been under a glue attack for a while, covering all the mating surfaces to the point of making the bonding ( in place) imposible.

I will clear all the mating surfaces and the mounting channel with a dremmel tool and then I will use good glue. I think perhaps model airplane/car glue might be the appropiate one. I will drive by the closest Model Hobbist store and find out.

I am posting some pixes of the lens and assembly after cleanup.

Yea...no "Rigor Mortis" pictures...those bugs deserve to rest in peace.

You guys know how the tailight is a one assembly , lense and reflector case.
In one of my Datsun cars the lens is separated from the reflector case, not completely, but enough to remain ajar.It is not broken, but it seems that the factory gluing agent is lost its binding power.
I will clean the assembly thoroughly and then I plan to use some adhesive to glue it back in place. I will clamp it to asure good bonding.
Has anyone done this before?? what would be a good adhesive/ glue for this matter???