2023 Tacoma, 32k miles, rear wheels locked up, snapping noise

Heres a really shitty picture I screenshoted from a youtube video. The Reaction arm is down on the bottom with the end circled in red.

Now, in a conventional system like was used on everything toyota made from the 70s through 2004 on the Taco and 2006 on the Tundra, all this bullshit wasn't there. Only the lever (circled in green) which pivoted high on the shoe and when pulled, spread the tops of the shoes by bearing on the adjuster (circled in blue).

The new system still does that, but ALSO, as the lever (circled in green) is pulled, it pushes the top of the secondary lever (circled in purple) outwards, which causes the bottom of the secondary lever (circled in purple) to move inward, spreading the bottoms of the shoes via the reaction bar (circled in red). The interface here is a rounded end that fits into a corresponding shape on the bottom of the secondary lever.




Now, one of 2 things is happening here. Either that sort of flat ball/socket type joint (circled in red) is getting hung up, or we have a shoe geometry issue. Keep in mind, the wheel cylinder ONLY spreads the tops of the shoes, creating a wear pattern as such. Then when we actuate the bottoms and the tops of the shoes, we're applying them in a manner that very well could jamb the shoes in the drum, if the shoe arc and the drum arc are not the same, which they never are. EVERY time I've experienced this problem, it has been with somewhat worn shoes (70% or less remaining)...not worn out, just not new.

If I find time, I might modify this back to a conventional type system and see how it works. The primary lever (circled in green) is typically pivots in a round hole or pin in the shoe...but in this case, it sort of moves in a slotted hole and pivots on the top of the secondary lever…and once it sees a load pushing on the adjuster assembly to spread the tops of the shoes, it forces the top of the secondary lever out (secondary lever pivot pin is right in the center of the shoe) and pushes the bottom of the secondary in, actuating the reaction bar to spread the bottoms of the shoes. The hole in the shoe will have to be welded up, redrilled, probably a new pin made, and then throw the secondary lever and the reaction bar in the trash.

My 05 did this every morning....parked in the driveway which was on a bit of slope, release the parking brake and the truck wouldn't roll...dump the clutch in reverse and it would pop free and we're good. Did it once on the launch ramp and that was not fun at all.

My 2016 does it after launching the boat...but again, no signs of anything on the drum friction surface.

I think the issue lies in the fact that there are 6 or 7 pivot/contact points in the mechanism for the parking brake on this style system vs 1 on the old style system...If each one of those has a little more friction than they should for whatever reason (wear, brake dust, moisture, etc...) it's game over.

 

Im 99.9% sure its your drums locking up.

I had exact same symptoms last winter, adjusted my drums and been fine ever since.

 

No shit?

 

sorry was too lazy to read the whole thread.

 

Tried to take the drums off, was extremely difficult (More then any other drum I've take off) and the shoes seem to be worn unevenly. Cleaned it out with some compressed air and brake cleaner, hopefully did the trick for now. LOTS of dust / worn pad came out. Seems to be driving better now, occasional grinding noise (happening in reverse only). I've notice they only lock up or make bad noises when I go in reverse. I was going to upgrade the brakes anyways since my front rotors are warped so I'll just do it all sooner.