Brakes locked up while slowing down

My wife was slowing down in our 2013 Tacoma when the brakes locked up. She said it isn't the first time. She tried to accelerate and the truck wouldn't move. The brakes finally released and she was able to get where she was going. Any idea what causes this? I did the brake booster check and it passed.

 

I’ll guess a broken rr brake cable. Buy oe, only.

 

I have heard of old hoses causing brake dragging , by kinking or internal layer peeling creating a check valve , or maybe extremely seized caliper Float Pins jamming the entire caliper assembly (?)

 

Thanks for the replies. I’ll look at the lines when I get a chance, but I’m far from an expert on brakes.

 

It would be worth it to just pay the $ to have a competent shop check it out then, for the sake of safety, (precious cargo and all that )
Problem is finding a competent experienced mechanic ( not just a parts changer )

 

Oh I will. Just thought I’d take a peek to see if anything bad is obvious.

 

So I finally got the the brakes to lock up for me. You have to come to a quick stop for them to do it. It only does it sometimes, not always. Then you hit the gas & gives you whiplash when they release. Gonna bring it to a mechanic.

 

So it’s not the brakes. It’s the transmission. Mechanic said it threw a code on his scanner. He didn’t give me code number. I’ll ask tomorrow.

 

Did the engine rev higher than normal before the vehicle started moving?

 

Not before I gave it gas.

 

Just for clarity the 4x4 and pre runner do not have floating calipers. They are fixed calipers. The 5 luggers have floating calipers

 

Freaking Lake Charles Toyota techs. Transmission was 3 quarts low with no sign of any leaks. I had them change the fluid a few months back. Been giving intermittent problems since.

 

Damn that sucks! Who did your srvice this time?

 

Good God.

 

Probably just filled it cold and never got temp up over 150 to open up the trans cooler lines. It is hard to get the trans up to temp on a lift and takes too much time to drop it, drive it, lift again then fill again. No excuse, that sucks, sorry to hear about that.

 

I took it to a local mechanic I've used for years. He called a local transmission guy who helped him diagnose it.

 

Thanks. When I pay what they charge, they should jump through hoops to do it correctly.

 

I agree, right or don’t advertise the service regardless of price but I’m sure it wasn’t free.

 

So I let Toyota dealership know of my issue. That tech is no longer employed there because of another mishap on another transmission.