There have been a few minor problems with the parking brake (no longer called an emergency brake) mechanism in the Toyota's Tacoma and Tundra models, which employ similar parking brake systems. Many of the problems have related to lack of use or faulty components that can cause the dashboard brake light to stay illuminated or cause the rear brake shoes to lock onto the rear drums. In addition, due to faulty workmanship, a recall was issued on the 2005 to 2006 automatic transmission models.
A nationwide recall was mandated in the United States by the National Highway Traffic Safety Administration on over 20,000 Toyota Tacomas with automatic transmission manufactured between 2005 and 2006. The was that the parking brake cable lock nut on the trucks may not have been tightened properly. This could cause the nut to come off the threads of the retaining bolt and fail to hold the vehicle if the transmission was not placed in the park position. Vehicle owners whose trucks applied to the recall were notified by Toyota and the problem was rectified at no cost.
The bellcrank cam on the parking brake is another problem with the Toyota Tacoma and Tundra parking brake mechanism. This problem lies more in the owner's misuse or lack of use of the parking brake mechanism than the parking brake system failing on its own. Again, automatic transmission trucks were more susceptible to the bellcrank cam sticking than standard transmission. This is due to more standard transmission owners using their parking brake more regularly then automatic transmission owners. Both transmission types could fall victim to this problem due to geographical regions. Areas that experience severe winter weather and use sand and salt on roadways would allow the sand, salt and other grit to contaminate the bellcrank cam protective boot. In time, the contaminants would cause the cam to stick or seize altogether. This condition caused the brake shoes (attached to the bellcrank cam cable) to drag on the interior diameter of the brake drum, or, in worse-case scenarios, lock the rear wheel up altogether.
Cleaning the corrosion from the bellcrank cam, lubricating it and then diligent use of the parking brake would rectify the problem. In cases where the bellcrank cam could not be freed or had to be hammered free, replacement of the bellcrank cam would be required.
In some of the earlier Tacomas, a return spring located on the parking brake handle mechanism inside the truck would not allow the handle to return fully. This would cause the interior brake light (indicating both brake fluid level and parking brake actuation) on the dashboard to remain lighted even when the handle was fully released. Pressing in the handle would work to shut the light off for a while, until the spring became even more compromised. Although this scenario didn't necessarily affect the parking brake mechanism, many owners were fooled into thinking the brake light was on only because of the spring problem in the handle. The Tacoma employs quad-piston calipers. This means there are four pistons per each front caliper. As the brake pads wear down, this system sucks more brake fluid from the master cylinder in order to maintain hydraulic pressure to the pads. If the situation of the brake light is ignored long enough, under the assumption the light is on because of the parking brake spring, the pads can actually wear down enough to the point of needing to be replaced. The light on the dash may now be activated by the low fluid in the master cylinder, warning the owner the pads are low. But since they're used to the light being on because of the parking brake spring, owners do not diagnose the problem effectively until the backing plate of the pads scrapes the rotors in a metal-to-metal contact.
