You want to know why no one mentioned that before your first post? Because it isn't true. I am sorry, but your contention that rust has spring like qualities that it will compress and expand and can cause a spongy pedal is total nonsense. You need to learn a little more about hydraulics before jumping in here and giving bad advice. Please go back to your fantasy world of being a super tech because it simply isn't true. No I don’t need a picture of someone’s box or certificates. My guess is you are probably a shop monkey and will just take a picture of a real tech’s box and claim it is yours.
And no, citing nonsense from another super tech lends no credibility to your story. An ASE master tech once told me to use a left handed crescent wrench. Does that mean there is such a thing? The problem I see with many of your web based auto techs who have never really turned a wrench is that you hear something and think you know what you are talking about because you heard it from someone special. For someone like Mike and I we see right through it, but for someone who is learning your bad advice can end up costing people money that may go out and replace parts that are really not needed.
You seem like you don't being told you're wrong. Didn't like the word 'no' as a child?
Again, no reason to lie to you. Why would I just simply make up the fact that rusty shims, compared to new shims, can add a different feel to the brakes? To impress you? To impress any of you? I could care less. I'm 28 years old and have been paid to work on cars since I was 15. And I'm honest enough that when I don't know the answer to something, I'll be the first to admit it.
Rusty shims are physically wider and have to be crushed down compared to newer shims. And again, let me clairify. If you look at the OEM shims, they're layered (we're not talking aftmkt here). When the shims rust, the layers seperate. Hydraulics doesn't have anything to do with it. Think of 10 pieces of paper laid down on top of each other. They'll lay flush pressed together. Now you put a kink in one or two of those layers of paper, and you'll have gaps.
You know what rust also causes? On the last gen Camry, it causes the rear caliper bracket shims (not the ones on the back of the pad) to start tightening up around the pads and locks them up which eventually causes uneven pad wear.The rust builds up on the bracket in between the shims and the bracket itself. So badly in fact, that Toyota issued a TSB stating to replace the caliper brackets and shims. People don't always want to pay for that (like my current customer in the shop) and you have to try and use a wire wheel to clean off the rust.
I've been the new guy on forums before. I get it, I'm the noob on the forum, you've been here since 2003 so you must be a king of some sort. Get over yourself.
And, just for you (even though you wouldn't believe me cause you're the best and smartest ever), I'm going to post pictures later of the Tundra frame I did last month, and the Corolla 2ZR motor I had to build 2 weeks ago. I'll post a picture of my toolbox, not someone elses. I'm too proud of everything I've done and accomplished to let someone on a message board degrade me because he thinks he's the king of the world.