Can rusty brake shim effect braking

When changing the front brakes on my 2010 tacoma I cracked the valve on one wheel to release the pressure while retracting the caliper. I know I didn't have too. I've never done it before and will never do it again. But I did it. End of that story.
Anyway, since then my brakes have been low to the floor and when I pump once they stiffen up. I took it it a mechanic to be bled and it was the same afterwards.
So I took it to a Toyota dealer and the mechanic said they were fine and he couldn't make them any better.
Then I took it to another Toyota dealer and asked them to bleed the brakes. They said they bled them as per Toyota instructions, but they are still the same. They are telling me the problem is that my shims are rusty and that's what is causing the problem.
This makes no sense to me as every truck out there will have rusty shims in short order.
Has anyone had the same experience and can rusty shims mimic air in the brake line?

 

No. The dealer is full of shit just as you suspected. You have air that has probably worked into the ABS Unit. The dealer or mechanic will have to connect and cycle the ABS System while bleeding.

 

They told me they did bleed the ABS. I can't go back to them unless I replace all the brake components to prove or disprove that is or is not the problem. They pads and shoes don't need replacing yet.
I'm running out of options and don't want to keep paying other people to not fix the problem. I have tried bleeding the brakes myself many times trying different things I've read on line, with out success.

 

I'm not convinced the Mechanic at the dealership believed what he was telling me. I think the shop foreman told him that's why bleeding didn't work.
He did tell me it was the second Tacoma he had worked on in as many weeks with the same problem and they didn't solve the first one either.

 

Most new pads come with pad shims. The Wagner thermoquiets have the shims built into the pad. A rusty pad shim may cause a brake squeal but not a spongy pedal.

 

I'm in total agreement with Jimmyh. Quick question: did you monitor the fluid level in the master cylinder reservoir while you were working? I ask because I experienced the same issue you are having. After trying to bleed the brakes several times and then taking it to my independent mechanic, I still had a spongy pedal. I finally gave up and took it to the stealer and they told me there was air in the ABS unit. Worked perfect after that. The Yota tech told me that the fluid reservoir likely got too low and allowed air to get into the master cylinder, which then worked its way into the ABS modulator. So frustrating, good luck getting it resolved!