Brake pads fell out

Usually due to lack of grease on the caliper slides..causing the caliper to no longer "float" and sticking making it wear one side much faster than the other.

 

This is a common problem. Usually a sticking rotor though will cause a pull to that side, and also typically only wear the pad that is located opposite the piston. That being said, the piston could be stuck, or a brake line failure that keeps pressure applied at all times. OP, I suggest also looking to see if the piston will compress back inside the bore, and also, as mentioned above, make sure the caliper slides are lubricated as well.

 

Every brake job I've done has had the piston side pad worn more than the outside pad. I couldn't say by how much, though.

 

If the piston side has worn more, then there is something wrong. A properly lubricated and operating disc brake system will wear evenly.

 

The inboard pad had worn more than the outer, but not by much. And the left side more than the right. When I replace all this stuff, I'll do a proper post mortem exam. I like to understand how things work. In this instance, the patient is ten years old and some parts had seen some hard miles before we met. I can't afford to replace everything right now; it'll have to wait awhile. Thank you guys, for all the insight and advice.

 

I didn't mean it as a contest. I'm always amused by creative automotive survival techniques. I don't see as much of that as I once did, now that there are laws about things like driving a car that is likely to fall apart without warning.

 

If you go by Toyota's recommended maintenance, you are supposed to "service" the brakes every 10k, which means lubricating the sliders, checking pad thickness and re-shimming if necessary. How many miles did you put on since you changed the pads?

The four-piston non-floating caliper in six-lug models can withstand a bit more neglect, but sliding calipers do require timely maintenance to function correctly. In northern regions with a lot of road salt, it is sometimes necessary to lubricate the calipers after every winter.

 

from the pick it looks like the pads were completely worn down? the rotors look grooved enough to replace.

 

+1

Rotors that far gone will likely be under spec once turned.... and I wouldn't turn them even if the shop said they'd be okay. I don't like anything more than a light surfacing every 2 or 3 pad changes. If I get "into" the rotor or any pulsing, I replace them.