Just make one from a bug sprayer, clear hose, plumbing fittings and a used MC cap. Buy the smallest sprayer you can find. You don't need a gallon of fluid but that is a common size sprayer. Drill a hole in the cap, insert plumbing and JB Weld.

Make the hose long enough to reach from the MC back to the rear wheels - even when working on a long bed truck. Lots of ideas on line. Total cost ~ $20 + your time collecting parts.

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.