So, with the wheel cylinders I currently have, a couple of things, and this may not matter to most folks, but the bleeder shaft is 1/4 diameter, originals are supposed to be 5/16, and the bleeder is much longer then the original or correct OEM replacement at 1.25inches, should be 1.0 inch length. It also has odd size head, 9/64. Now, most standard wrench sets don't have that size so it makes it more difficult when bleeding as you have to open close by hand instead of using a wrench to open close, and may not fully seat when closing by hand. This is a also a problem when using speed bleeders as they don't fit because the cylinder has this odd size bleeder.
Aside from that, I read through a lot of comments from people that have purchased the ones currently on my car and on various sites, people have reported an issue due to the design of the thread and shaft length that these can actually pull air in around the threads when bleeding, and I believe I have seen this problem when bleeding as I have seen very tiny bubbles in my bleeder hose and this leads to never being able to completely get the air out of the cylinder.
I guess this is a symptom of stuff being made in China, as most of the aftermarket replacements are made there, so in my hunt, I found the Bendix site, and they have ones with the correct OEM bleeder size etc. So I will give these a try and see how it goes!
