I am due for new brake pads and pulled the RF to take a look. This is how the slotted shim looks:



You can see there is a plastic-like film covering part of the shim that has started to peel. Do the shims have plastic coating that is intended to be left on when installing, or did someone fail to peel it off? If it's supposed to remain on there, is the shim now useless or can i peel it entirely and use grease or some sort of anti-squeal?

the pic isn't showing up.

my guess, is that it was supposed to be removed. a lot of times the shims have a sticky side, and that plastic it meant to be removed to expose it. its not a big deal either way. pull the shim, and remove the plastic, reinstall the shim.

Pic is there now, I always forget that Google drive requires me to jump through some hoops to embed a shared image.

Whatever it is it's not easy to remove. I tried soaking in brake fluid with no results. Next tried mineral spirits... maybe loosened it a little where its already peeling but not much.

Finally hit it with a little torch and made it bubble a bit, now soaking in mineral spirits again. Tough adhesive.

Mine didn't have shims, do I need them?

I don't think that they are necessary if you get replacement pads that have the metal backing where the caliper pistons make contact.

You should have had a second shim that goes over the slotted shims. They come coated with a black rubber/plastic film and are placed between the pad and outer shim with a light coating of brake grease on both sides. They are supposed to be cleaned and re-used with new Toyota brake pads if in good condition. Unfortunately they are now technically ruined.

As you can see in the following picture in section 04945 you can see how the shims are intended to be placed on the pads.



If you are using Toyota brake pads (the good ones, not the cheaper ones, they come with their own shims), then you need to buy a new set of shims. If you are using non-Toyota brake pads you don't re-use the shims as most aftermarket pads come with their own shims.