It looks like your brake shoes have beveled leading edges. This is the thing that is done on normal cars but Amphicar left the shoes with square leading edges to better wipe the water off when coming out of the water.
As much as I love Hylomar for normal gasket applications, I continue to use red brake grease up to and including where the boots snap down on the cylinder. I rely on really tight fitting boots to do that job. I found such boots that are tight on the small front cylinders at Whitepost brakes service. I couldn't find them anywhere else even though they are an American make brake boot. Whitepost did sell them to me but it's not there main activity. They were also able to supply the larger push piece for converting a VW master cylinder to be correct for the Amphicar push rod and it's larger diameter. They've been in business forever and know just about everything about brakes.
This is the way my set came from being re-lined by Gord. The material that his vendor uses is supposed to be excellent at stopping -but I imagine I could take a fiber cutoff wheel on my Dremel and carefully make a cut to remove the taper and create a more perpendicular "wiper" leading edge .
Sounds like something I could try I will try to reply back with pictures
gord – share any thoughts on this if you happen to see this post !
Thanks John F - I happened to talk to John Bevins, and he said that the square edges were regarded by the design engineers as important for the increased "wiper action" to shed grit and water more quickly - I looked at the rivet locations on Gords linings, and theres not much room to risk trying a perpendicular cut to eliminate the taper. John B also mentioned that a plumb edge helps "bulldoze" away grit or waterborne debris...that the sedge shape might trap and scrape the inside of the $$ drums.
I called Gord and he said he has supplied tapers on his super-stopping-power linings for 15 years without an issue and that they are softer to begin with (maybe 10k miles), and that reduces the chance of scratching. People seem quite pleased with the great stopping power, so i i will leave em as delivered and see how they work for me.
I know this is an old thread, but time to update it as I finally pulled my drums off the front just to see what was there. The picture is my drivers (LH) side.
As I suspected, someone (me) put the backing plates on the wrong side, and thus poor braking performance has been the result. I guess it is possible I put them back how they came off, but either way they are not right.
I am actually happy to find this as removing them and switching them is going to hopefully make a pretty significant improvement in braking.
They also were adjusted a little loose, so that can be tightened up a little too.
I had a feeling this thread was going to be important to me when I read & responded to it so many days ago. I really appreciate everyone who provided input and information to the forum record!
I fought lousy brakes on one of my cars for years before solving this one out. I'm embarrassed to realize how many other ideas I tried before figuring this backing plate issue out. You will find this will make your brakes MUCH better. Nothing subtle about the change.