Rear drum brake locking up after getting wet

I was hoping to get some input from the forum on this situation.

So today is the third time I take my 2018 TRD off road to the dealership for the same issue. For some reason, every time my truck gets wet (after a car wash for example) one or both of the rear tires tend to lock up. Sometimes it's mild, and other times the car is not drivable.

So I first noticed this after buying the car. The morning after a car wash, I would shift into drive and the car would not roll forward. After accelerating a bit it would make a clunk noise and bounce forward like something was seized up and just released. Out of habit, I pull the parking brake every time I park. I noticed if I didn't pull the parking brake it wouldn't seize up as bad but it would still happen.

Eventually one morning I couldn't drive out of my garage. The driver rear tire was completely seized. The opposite rear tire would spin in place basically. If I placed it in 4wd I could inch forward but the seized tire would just skip along and not turn. I disassembled the rear drum and while doing so it was obvious the brake was engaged for some reason (car is in neutral and of course the parking brake is not pulled up into the "on" position). After bumping it with a hammer and using the release bolts I was able to take the drum brake off and everything inside looks completely fine. Nothing broken, rusted or unusual looking. There was really no moisture inside either. I reassembled it and it ran completely fine up until the next time it got wet. Same situation except it was the passenger side wheel that locked up this time. Repeated the same process and again worked fine, up until it got wet again.

I took it to Toyota and explained it was both sides, even showed them video clips of what was going on. They kept it for a few days and eventually said one of the parking brake cables (I think it was the left one) had a crack in it and was letting moisture in which was causing the line to seize up and not release the drum. Before driving away I pulled the parking brake, felt fine, put it in reverse and couldn't even drive out of the parking spot. The opposite rear wheel had locked up. They kept the car for a total of 10 days. They said they replaced the cable on the opposite side as well. Apparently they didn't have the part in stock and thats why the kept it 10 days.

I washed my car a few times afterwards but out of fear this would happen again I didn't touch the parking brake. Today however, I washed it and needed to go out for groceries afterwards. I pulled the parking brake out of habit and when I went to go drive it again it was locked up again! After rocking it back and forth between drive and reverse it free'd up and I took it straight to Toyota.

The shop manager says he hasn't seen this before. I looked online and some posts mentioned similar issues after boat ramps or car wash, but it sounds like no one had it lock up the same way mine has.

Anyone have any idea why this could be happening? It doesn't seem right that I can't use my parking brake after the car gets wet. I don't understand why both sides lock up at different times. It's obviously not the parking brake cables. The car only had 12k miles on it when it locked up the first time so it's weird that both cables would have cracks in them. Also it's now happened with brand new cables. I can't think of why it would be working perfectly fine, and then gets wet and locks up completely.

They said they would call me tomorrow at noon after they have a chance to run diagnostics or whatever. I'll let you guys know what they say.

Anyways any input on this would be appreciated. I feel like there's more knowledge in the forums than in the dealership most times. I'll try to upload a video of what's going on too.

 

Mine does this too, but mine does it from freezing. I gave up on the parking brake in winter.

 

I thought about this too but the car sleeps in a garage that never gets below 40. Also it's immediate as in it's working fine, gets wet and now it's locking up.

 

Here's a clip

https://vimeo.com/392133937

 

Yeah, that’s not right at all.... isn’t the parking brake on these trucks self adjusting? Perhaps when pulling the brake it’s adjusting too much.

 

I suspect water in the brake drums, but it shouldn't be that bad. I washed the salt out of mine the other day and htere was an audible pop when i moved it out of the garage later, but nothing like that.

Does it still do it if you take it for a drive immediately after washing?

 

Today I drove just a few blocks and it happened. The drums may have been wet but every time it happened and I took the drum apart it was actually pretty dry inside.

 

New water activated braking system... normal.

Kidding of course. Evidently, this is a pretty common problem in the automotive world:

https://www.google.com/search?q=rea...rome..69i57.7631j1j7&sourceid=chrome&ie=UTF-8

https://www.brakebleeder.com/rear-brake-drag-lockup-drum-brakes/

 

Yea it does. This happened once immediately after a car wash. I pulled forward and it locked up. I cant remember if I had the parking brake engaged or not while I washed it.

Also, I don't use a pressure washer or anything like that, just a regular old garden hose.

 

Thats gnarly. They replaced the parking brake cable, seems like replacing all the rear brake components would be a relatively inexpensive fix for this issue. Why haven't you/they just replaced both rear drum assemblies?

 

Holy shit... It looks like you made it to the freeway before yours started locking up?

I know other folks that reported this issue here on the forum only had it after letting their car sit after a car wash. If they drove it after it didn’t happen anymore.

 

Clearly you should never, ever, under any circumstances, wash your truck.

Reminds me of my neighbors boat for some reason. At the factory they installed the fuel tank vent backwards, and so it would always pick up water and he'd have water in the fuel. Eventually turned it 180 degrees and never had water issues again. Makes me wonder if maybe there's just something a little off about yours. Not sure what that would be though, drum brakes are a pretty well-understood technology.

 

I almost wonder if the brake shoe is loose and getting caught up and jammed against the inside of the drum. That doesn't explain the car wash issue though.

 

The brake bleeder site is pretty helpful. I think when they refer to lock up they are describing a scenario when while driving you press the brakes, the rear tire or tires lock up, you release the brake and the tires spin freely (sounds like its from the sensitivity adjustment).

This I think is different. Once one of my wheels locks or seizes up, it will not free itself unless you manually remove the drum, or like today where I was able to rock it back and forth and free it.

 

Yea I agree. I'll see what the dealership says when they call tomorrow. But I think all of it needs to be replaced unless they can definitely prove they know what caused it. So weird that its both sides though, on car with less than 15K miles.

 

This has happened to me a few times.
Not after a car wash though. Every time I was on a slight downward slope.I pulled my car out of the my garage the other day and stopped put it in park and applied the hand brake ,I was on a downward slight slope and when I put it in drive and released the handbrake went to drive away it wouldn't move. So I gave it more gas and one of the rear wheels spun and the truck still didn't move forward. But then I put it in reverse for a few seconds and it moved so I put it back in drive and it was back to normal operation

 

Throw that rear locker on next time you get stuck on the road. Should free it right up.

 

Damn... ya got me on this one. a really long shot... but maybe the brake pads were fab'd incorrectly with some impurity that absorbs water & expands the pad?

 

I wonder if its related to the TSB for brake pedal vibration that supposedly is caused by a rear axle shaft/drum brake issue. It's possible your truck could be on the far end of the bell curve when it comes to shit being out of spec. TSB-01710-16 has been around since 2016 but I feel like trucks have had it for years and dealers act like youre crazy and theyve never heard of it when you tell them your rear brakes are acting weird.

 

The first time it happened I thought about doing that but I'm glad I didn't. I'm sure the locker would have lost. That drum was seized hard.