Hello Elwood, I am quite certain I was the first to dismantle the front brake caliper of my 74 CB550. What I found behind the puck and on the atmospheric side of the piston was a transluscent, white-ish grease. Felt like silicone. The Honda maintenence manual has a note in the reassembly instructions, which reads: Apply silicone sealing grease to the pads sliding surfaces of the caliper before assembling pad A and B. This serves as a dust preventive as well as a water repellant. Do not apply grease on the pad friction surface.
I have doubts that plating the puck is going to offer a solution to the caliper corrosion problem. It will still be a different metal than the aluminum alloy caliper body. Plating will likely delay the rusting until the plating wears off. However, as long as the bare aluminum is exposed to atmospheric humidity, water vapor, or plain water, the exposed aluminum in the caliper is going to corrode and build up the white product typical of aluminum corrosion. The cleaning method of the aluminum should also be noted. The cleaning of aluminum should NOT be performed with any steel product. Steel wool, or even stainless steel wool should not be employed as it leaves tiny bits of the abrasive embedded into the aluminum surface. Once again setting up for dissimilar metal corrosion on a microscopic level. Aluminum oxide or silicon abrasive paper is acceptable as is Scotch brite type abrasive. The aluminum treatment recommendations come from the aircraft preservation sector. Aluminum, their alloys, and Alclad are prevalent in the aviation world. Airplanes don't tolerate the loss of much of their structure. Pure aluminum will make its own protective surface layer of oxide which is effectively resistant to further corrosion of normal atmospheric elements (not including acid rain). However, aluminum alloys do not form the same level of protection. I'm pretty sure the caliper on our Hondas are made of an aluminum alloy. So, it will need to be protected from exposure to the elements to prevent corrosion. Honda engineers determined silicone grease was effective for this application. And, I agree with their decision. I've already posted my recommendation of High Temp Vacuum grease from Dow Corning. This stuff will not mix with or be washed away by water. And, it is a transluscent, white-ish grease that provides an effective film coating over the bare aluminum of the caliper. Cheers, Lloyd SOHC4 #11 72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F, 78 750F [EMAIL PROTECTED] wrote: >-------------------------------1073938838 >Content-Type: text/plain; charset="US-ASCII" >Content-Transfer-Encoding: 7bit > >This brings up my thoughts on your problem, Hoyt. The chemical reaction of >the two dissimilar metals... The corrosion of the AL and the rust of the >puck... The plating sounds like a solution. > >Elwood > > >
