These confirmed to work well on the 939(a2) air brake drums, front and rear? Not sure there is any difference as compared to the fluid 809 series drums. I’ll take one if so, don’t cut it up, I can provide a UPS or Fed-Ex account number to ship on. I have a new 24v gear reduction starter or 70a 24v alternator to trade if you’d rather. Either fit 809 series 250 engines which I think you have. Or cash is OK. Please and thanks. We can PM details. I want the yellow one, will look cool hanging on the wall, will tell everybody it is for something different.