Continued progress on my '90. After trying to correct the 'low washer fluid' indicator, then watching the fluid run all over the floor, I managed to remove both parts of the washer bottle and attempt to patch. I wasn't sure what to try, but Harbor Freight had plastic welding rods for $6 (then added a 20% off coupon and free flashlight) so I thought I'd try it.
I found the green rods to work the best, and a big iron. A Weller gun has the power, but not the contact area, so I dug up an old 'pencil' iron that was probably 80-100 watts, with a big tip (lots of reserve heat and surface area). Placing some rod in the gash, I worked the iron into both the old and new material, then kept adding more rod.
Once my welding was done, I put water in the tank and checked for leaks...none! I then added some RTV over the patch as a precaution and also where the support strap would go for cushoning Reinstalled and fluid added. No leaks!
Dave

 

That's great Dave, but where are the pics?