Steering pinion casting

More steering problems!

I stripped my rack and pinion right down to the main tube. I wanted to get the tube powder coated. The aluminium pinion casting stayed in place. Unfortunately, while it was hanging in the coating shop's oven, it fell off. Now if it came off that easily, an apparent result of differing rates of heat expansion as between disimilar metals, I shouldn't have too much trouble putting it back on the same way, I being possessed of both a propane torch and a yard full of snow. The troubling part is getting it back on at exactly the right alignment. I have another old rack I can use a a guide, but it seems it would be very easy to be off by a few degrees. How critical is this? Also, there was some dried sealant or adhesive left in the casting where it joined the tube. What do you think - JB Weld, silicone ?

Thanks.