Thanks for the info Greg. You are reconfirming what I have learned and heard over the years. I like to be cautious though.
Mike I am just giving information on the procedures and recommendations for our particular line of BCs. I know Oceanic recommendations are the same but others may be different. As for what can be replaced in an BC annual...For starters the exhaust valve poppets(the part of the valve that seals and opens and shuts when you pull on it to dump). Second the inflator valve is inspected and in some cases rebuilt or even replaced. If you have an alternate air/inflator it is rebuilt and inspected like any other regulator would be. Of course everything is inspected for good condition and replaced if necessary. This inspection would include springs, cables, etc.
As for filling the BC with water to rinse, the easiest way is to press the deflate button while pouring water into the inflator valve. The best way to accomplish this is with a hose but it can be done in a bath tub with the faucet. Then drain the water out of the dump valves or hold BC upside down and drain out of the inflator valve.
As for reuse of sealing parts this is not just an arbitrary dive business thing. Gasket materials have come a long way since days of old. Cars used to use lots of cork gaskets now things have moved more towards synthetic rubbers, crush metals, paper/fiber based; etc. They use whatever is most suitable. Many could be reused. But when working on critical things like fuel systems, I prefer replacing any old seals that are removed with new rather than reusing. That is that industry's standard as well.
In aviation many things are replaced and rebuilt on set schedules automatically. Wether they have failed or not. It is a proactive approach to safety. Getting a new gasket is cheap insurance in most cases.
You may be thinking a BC is not that critical. But it helps you go into and back from an alien enviornment safely. If it fails at 100 ft you will think it very critical.
At the very least if you proceed to reuse gaskets please leak test your equipment in water before going on dives. I still stand by what I said, and I can not recommend reuse of those gaskets on our line of BCs for the reasons stated above. I could not recommend it for any brand either. Unless, that is within that manufacturer's service guidelines. Ask them they would probally be glad to tell you what their recommendations are.
As for Durometer testing and the such tests at your LDS. It is far cheaper to replace the gasket than to go to those extremes. The risk of having a leak is probally small for reusing that gasket but so is the cost of that gasket, cheap insurance. But if they do not follow manufacturer service procedures please inform said manufacturer.
The engineers that designed the BCs put them through lots of tests. Do you not trust them. Maybe you should reevaluate the use of the BC if you do not trust the engineers that built it. I would if I were you. I implore you to find out their recommendations on any dive equipment you use. Some manufacturers even have their own sections on this board including mine Aeris for questions such as this.
I myself am a do-it-yourselfer at heart. I understand where you are coming from, and I can appreciate it. I wish that those that want to learn to work on equipment, and buy service parts could do so more freely. I wish those who would like to learn could recieve factory authorized training. But the policees in place are not likely to change anytime soon, and there are good reasons for them to be in place. Control over the quality of equipment service being one of them. For now one must be affiliated with a dive shop to recieve parts. Short of buying from gray markets.
Proper rinsing and anual service should be adequate. If you wish to be thorough, take care rinsing each valve separately while working the mechanism. Really drench the valves with fresh water while working them. If you do so; dissassembly should not be necessary until annual service. If you still have leaks, I suggest you get service. Most divers simply rinse their gear and get service anually without issue. I would hear about it otherwise.
I think you can understand my point of view obviously yours is different. I understand your point of view as well. But there is still a risk however small. I can not recommend it especially since the service procedures state otherwise. It would be negligent on my part to recommend your practice. I agree to disagree with this one. Like anything else in diving safety is in your own hands. Remove risks where and when you can.