I have a broken reverse drum in a 26 engine I am building. Does anyone know what years are interchangable? Has anyone had good luck welding or brazing these trans drums?
Reverse drums are very common to find and any will interchange. Welding/brazing can and has been done but will put the drum out of balance a bunch from what I have seen. Find a replacement drum, you will be better off IMO.
Broken like in pieces or just a crack from the rivet to the lightening hole in a couple of places?
Here are a couple of pictures posted by Joseph Magedanz in 2009:
Most reverse drums seems to develop cracks. It's commonly thought that if a drum only has small cracks from the rivets out to the lightening holes like in the second picture (but not anywhere else) then they can be used without much fear - but cracks going towards the outer rim is something much worse and could result in a drum failure.
Remember the tales about using the reverse as a brake? It should only be tried when in a catastrophic emergency - a reverse drum isn't beefy enough to stand for more than a fraction of the abuse a regular brake drum can take.
Here is my post on cracked revers drums:
http://www.mtfca.com/discus/messages/257047/276198.html