Man, I thought I was somewhat older Macks (I was weaned on a B61 Thermodyne, 20-speed Quadraplex transmission). I have operated Mack triplexes, duplexes, and 5-speeds:B-models, J-models, R-models, U-models; and as far as cabovers go, I've driven H-models and F-models, but yours is a new one on me. Although I retired as a Peterbilt-man, my heart goes to the Macks, maybe because I'm originally from Pennsylvania (Mack country back in my day).

You may need to loosen the slack adjusters and start banging around with a hammer and a good rust arrester. If you have "Maxi-brakes" you will want to address the, but they can be dangerous and I recommend you get some istruction from a mechanich before messing with then. I'm assuming you have taken some wheels off to look at things and probable can't get the drums off because of the situation. Call Mack Trucks and talk to an old-timer for some advice. I'm certain they would be glad to advise you especially since your baby is probably a Classic. Maybe they will want to byuy for their museum. The will, at least know about collectors, I bet.

I'm not a mechanic: I'm just an old truckdriver with a soft spot in his heart for the old Macks. Sorry if I 've wasted your time.

God bless you.
"The world famous Zig-Zag Man"