2021 Rust Behind Drum Brakes

Did Toyota intend to bolt a chunk of rust between the rear axle housing and brake shoe backing plate? This 2021 2WD SR5 has less than 3000 miles on it. After drizzly weather, the rust runs down over the inside of the rear wheels and makes rust puddles in the driveway. It seems to me that Toyota might be willing to do something like a POR-15 fix or parts replacement for this. I don't know if anybody else has this problem or if it was related to a temporary supply chain problem. The truck was built in San Antonio.

 

Yes, this is normal

 

What was the purpose of this design feature?

 

to get you to go in and pay to have it replaced

 

These are mating surfaces, you dont really want paint on them. So they dont paint them. That plate will in all honesty live longer than you. The titanic is only 3/4 inch thick steel, and its still sitting on the bottom of the ocean.

 

It’s not just yours. It’s normal.

 

I guess I could stop the rust on the exposed surface without creating a safety issue. Thanks.

 

Yes you can. Now that things are bolted together, shooting some paint on them isn't going to hurt a thing.

 

A lot of the forged parts aren't painted, another example would be the front suspension spindles (aka knuckles). Toyota has been building them this way since 2004 (might even be earlier). Unlike the thin-walled parts (frame, body panels), the rust on forgings doesn't seem to get worse or cause material loss. The wheel bearing will give out long before anything bad happens to its housing.

 

That's the bearing.

 

It isn’t something to worry about mechanically. There are dozens of parts in vehicles that will just rust over time. Not to say I like seeing rusty parts, but other than improving cosmetics, painting it won’t do much else.

 

The op should look at some castings on/around the front differential. That cost even more to replace if rusty.

 

I coated all of that with some HD metal protector. Still looks brand new after a few snow storms and lots of salt on it. You could also put some paint on it if you'd like. Use a wire brush and knock off anything on the surface and then put a few coats on. Not gonna hurt anything down there. Like others said, this will just keep the rust stains off the concrete...no structural damage will come of leaving it as is.

 

Buy a can of FluidFilm and just spray any rusty coloured parts underneath your truck....

 

I'd say it will take about 80 years for that to rust through. Better get it taken care of!

 

Oh my, thats a tragedy. I hit the brake backing plates with some cosmoline 2 years ago. So far seem's to be still good after all this snow and salt. I thought it might burn off.

 

Isn't that cardboard between the drum and axle stupid? I ripped it off and put anti-seize instead.

 

It is. I did the same.

 

Yes, it's mostly double stick paper like and yes I scraped it off and added anti-seize

https://www.tacomaworld.com/threads/rear-axle-brake-drum-gasket-why.710012/