BTFD 3227

Thanks guys. Makes sense. I appreciate the information. Hopefully I can find drums now and get this old girl back on the road soon.

Getting ready to start rebuilding the rear hubs on our B85 and have a couple questions. First, are both bearings oil bath or is the outer oil bath and inner greased? Second, if both are oil bath, what’s the purpose of the inside seal between bearings and how does oil get back to the inner bearing? When I disassembled there appeared to be grease residue on both bearings. Sludge. Looking for guidance from the masters.

Thanks Geoff Aftermarket seems like it may be my best option. I’ve talked to a couple of individuals up north that may or may not have drums laying around somewhere in their collection. The stamped steel piece you mentioned, is it separate from the drum and hub? How does it attach? Just wondering if something like that would solve my concern in case a seal fails. I need to figure out if it’s even needed.

Yeah, I’m finding out that the hydraulic brakes on these older Mack’s are rare and rather unique. Especially the rear brakes. I’ve got a casting number off of the good drum but nothing crosses over. The rear shoes are 15x5 and are rare as well. I’m wondering if I source a set of drums without the concaved bowl, which I’m guessing is by design in case of a seal failure to stop oil from entering the drums, will there be any issues. Unless there’s a seal failure. which brings me to another question,,, is the inner bearing a grease bearing or oil bath? If it’s oil bath like the outer, then why is there a seal in the middle of the hub? Another topic for another day I guess.

Greetings all and thanks for letting me in. New here but have been reading along as a guest for a while but can’t find the information I’m in need of. I’m working on a 55 B85F for our local Firefighters Union and need some help locating rear hydraulic brake drums. At some point the rear brakes have gotten really hot and the pass rear drum broke. The driver side is intact and can hopefully be turned out. Does anyone out there have or know of a source for these drums? Or an aftermarket alternative. I just need to find drums to get this old girl stopping again. Any help would be appreciated.