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I am trying to diagnose why a 2009 Toyota Venza's parking brake is not holding the vehicle securely. On any incline the vehicle will slide in N, never mind D or R.

After taking the rotor off, I observed that the shoes barely move when the parking brake is applied. Short videos of engaging/disengaging parking brake with wheel and rotor removed: https://i.imgur.com/QhhKml4.mp4

https://i.imgur.com/qEoVDUK.mp4

Is this the expected range of motion?

The brake cables where changed (one OEM, one non-OEM), as were the brake shoes and most of the parking brake hardware, and later the rotor/disc/drums as well. It was adjusted several times by multiple mechanics. The parking brake pedal has tension as soon as it starts moving and feels quite firm when fully pressed to 6-8 clicks and even before.

EDIT: After fully taking apart the parking brakes to inspect, clean, lubricate, and reassemble, I noticed:

  • The non-OEM cable might be slightly shorter than the OEM, because when applying the parking brake with the disc/rotor off, the parking brake lever reaches the metal stop on the dust shield, indicating full travel, and then jumps sideways past the stop. That is the loud "click" sound in the videos above. When it is inside the rotor it might not be able to make that lateral motion. The OEM cable on the other side brings the lever to the stop perfectly and no more. I wonder if this imbalance can cause some problem in the force applied or if the equalizer can manage this. Also, the non-OEM cable is clearly of lower quality: the head is smaller, the cable is thinner, and a few strands are already broken, probably from when a technician was trying to install it. It's a pain to work with compared to the OEM cable.

  • The parking brake's stopping power is not the same in the forward and reverse directions. With the parking brake engaged and the vehicle jacked up, I can't manually turn the wheel forward, but with moderate effort can turn the wheel in reverse.

  • The brake shoes do not appear to be making full contact. There are patches where some wear from contact is visible (shiny, metallic appearance), and the rest of the area has a matte dusty look. When I put the shoes inside the drum to check shape and tolerances, there seemed to be very slight imperfections which allowed me to rock the shoe to make contact with different sections. Very slight, but perceptible. Perhaps bedding in the shoes will wear them to match the drum and make full contact. I wonder if that would provide enough friction to hold the vehicle. The service manual includes a bedding procedure (step 24), and I highly doubt it has been done.

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adatum
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Several things can limit the shoe travel. Make sure all the cables are fully extended. Don't rely on the spring to move the cable, grab it with pliers and yank on it. If it moves any distance the cable is binding in the sleeve. Another issue is the top spreader bar being worn at the shoe contact points. This causes the shoes to seat to far from the drum. Low quality shoes can also cause issues. They can be lined with material that is too thin or not evenly round causing less than full contact. Some manufacturers did a poor job of designing early versions of disc brake parking brakes. Hence the change from "Emergency Brake" to "Parking Brake". Some models are marginal at best. Anything less than perfect, results in less-than-ideal performance. My state requires the brake to hold to 1200 rpm. My early 2000's Chevy Silverado with all new parts would roll at 1250 RPM. This may not be your issue but the days of the Parking Brake keeping you from driving away are long gone.

mikes
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http://www.tovenza.com/parking_brake_system-659.html

https://www.toyotanation.com/threads/is-2009-venza-parking-brake-adjustable.1008002/

Your rear brakes are drum style using brake shoes. Apparently the repair shop doesn't know how to adjust the star wheel that's adjusted after repairs are made then follow up to check on park brake operation. Perhaps the two links above can help you understand drum brakes and parking brake adjustment that go hand in hand as the rear drum brakes are the parking brakes. Many without knowledge of drum brakes are easily confused by the numerous parts used but forget or ignore drum brakes were the first brakes used since 1900 before disc brakes improved on braking in the 60's. When rear drum brake shoes are adjusted correctly by a competent mechanic or diyer, brake shoes drag slightly on brake drums. Applying the parking brake lever or pedal simply engages either a cam or other lever to force brake shoes against drum. When adjusted correctly, braking is better and engaging the parking brake should force the brake shoes against the drum to hold a vehicle from moving. Perhaps using the suggested links to Toyota forums can help you or search for other Toyota Venza forums for help. As a diyer, I'm familiar with drum brakes and maintained them in the past. As safety items, brake service isn't for anyone unfamiliar with servicing drum or disc brakes. I'm not surprised that your repair shop isn't capable of performing a complete rear drum brake service including park brake operation. No hydraulics are involved as this is all mechanical.

F Dryer
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