Back Brakes

I have a 2009 Tacoma and the back brakes squeak when I back up. They don't squeak when I put on brakes going down the road. I checked the shoes and they had lining on them. Have about 63,000 miles on them.

 

Easy fix that my mechanic showed me. Take of the drum, blow out everything with an air hose both inside the drum and the internals, spray brake clean liberally on the same parts to clean any left over dust out the reassemble. This should eliminate, or greatly reduce, any squeal. In my case it almost eliminated it so I'll have to do it again at some point, just doesn't bug me enough to deal with it currently. Oh yeah, wear a mask or respirator to keep the dust and break clean out of your lungs. It's not fun.

 

I'd say try a bed in procedure first but most of the braking is done by the front.
There's also different anti squeal lubricants. I've seen people scuff up pad surfaces.

it's specifically stated not to use compressed air around brakes. Due to making airborne hazardous particles.

It's not hard to take parts with a bucket underneath, and clean them with things like chemicals, water, brush. Things that are wet. Liquid reduces or prevents that.

Brakleen is also liquid. Cleans. Then quickly evaporates.

 

Brake dust & glazing can both cause squeaks.

What I do. Once the drums are off, just setting them down lug studs up will knock most of the dust off. Put a drain pan under the backing plate. Stand back, hold your breath, spray with brake cleaner to wet it. Then more brake cleaner to wash it clean. Look at the drum & shoe surfaces. They might look shiny. Use emery cloth to scuff the drum surface EVENLY AS POSSIBLE. Even if you’re not careful to do it evenly, you’re not taking much off so it shouldn’t cause any problems. The shoe surfaces, very lightly scuff the shine off. Lightly because you’re taking off friction material shortening it’s life. Then I like to wipe off the drum surface with rubbing alcohol and a clean paper towel.