In the continuing quest to re-furbish the Bofors (although this thread will be relevant to a whole range of vehicles), I got around to stripping down the hubs to re-pack the bearings and do a general clean up. The brakes had not been particularly effective, despite nearly binding on the drums. When I opened everything up, it became clear why.
The oil seal for the wheel bearings does not deserve the title of "Seal" as it's actually just a felt pad that catches the w.b. grease and prevents it from slopping out of the bearings. When the vehicle has been standing for some many years, however, all grease becomes fluid to some extent and the grease runs down inside the backing plate and pools at the bottom of the drum. Roll the vehicle any distance and you smear that grease all across the readily absorbent brake linings.
So here's the conundrum. The brake linings and drums are smooth and not scored at all. The linings themselves are full thickness and it would be wasteful to throw them away. Now the surface of the drum can be degreased quite easily, but what about the linings? Can they be cleaned of grease/oil sufficiently to render them serviceable?
I had thought of a couple of ideas:
1. Soak the linings in a solvent like Petrol, Shellite or (if I win the Lottery) Brake Cleaner to dissolve the grease. This might take some time and changes of solvent. Or,
2. Soak the linings in an alkali such as Caustic Soda to chemically degrease the oil out of the linings. Or,
3. Burn the oil out of the linings with a propane torch, as these are old spec linings made from Asbestos. And,
4. All of the above!
If these cunning plans are no good (and feel free to tell me why. I
am aware of the dangers of chewing on Asbestos), what would be better; buying NOS old linings or getting new-made bonded linings put on the shoes?