I just reinstalled the rear wheel on my 70 DT1 after replacing the rim, spokes, bearings and seals. I am unable to install the hairpin clip through the end of the axle unless I leave the washer off between the two nuts. I have taken it apart and inspected it twice and everything seems to be together correctly. The only thing I am unsure of is the play in the brake plate which seems excessive. The torsion rod is not yet bolted up. The first photo I am pushing the brake plate towards the drum and the second pulling the plate away from the drum. There is about 2mm lateral play in the brake plate. Thoughts anyone?

It will be fine. Probably a bearing isn't 100% seated in the hub. Once you crank the axle nut down to spec everything will settle in. After a initial ride re-check the axle nut torque and you'll be good to go.

Thanks. Like I said, it all looks good, but just second guessing myself since it has been a long time since I have worked on this bike.