Parking brake will not release

NO. A broken cable and/or spring, yes.

Prolonged lack of use and the exposure to the outdoor elements most likely caused the shoes to freeze in place and/or rust to the rear drum. READ: '04 - Rear wheel stuck: Brake shoes? Cable? | PriusChat

 

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If the brake shoes are seized to the drum, it's going to be a PIA to get the drum off. Chock the front wheels, make sure the parking brake pedal is released, take the tire off and smack the hell out of the drum with a mallet first, as that would be the easiest thing to do to try to unstick the shoes from the drum. Mechanical agitation can work miracles sometimes.

If the cable is frozen inside it's sleeve, (shoes not seized to drum, but still clamped to the drum) the drum brake should have a rubber cover over an access hole in the back plate. Remove this rubber plug and there should be a "star" adjuster there. Back off the adjuster and the shoes should loosen.

This assumes the Prius drum brakes are similar to normal drum brakes. I've been fortunate enough to have never needed to mess with mine.

 

yeah your right not sure what I was thinking you will never get the hubs off if the parking brake engaged.

 

Rather than smacking the drums with mallets, you could try pushing them off the hub with a pair of M8x1.25 bolts in the holes provided there for the purpose. If you have made sure the parking brake pedal is released first, and wiggled the cables as much as you can going into the brakes, the motion of the drums being pushed off as you tighten the bolts will start to pull the shoes along with (the shoe hold-down springs allow this). That will angle the shoes away from flat against the drum, and probably break them free. Even if they stay extended, you'll be able to force the drums off that way. Shoes may be a bit shredded when you're done, but I might plan on replacing them and the levers/struts anyway.

-Chap

 

If the drums are frozen and you could get the vehicle to a paved drive (assuming you have a paved drive) then towing the Prius in neutral with the brake released generally will free them up. Expect some skid marks on the pavement prior to the drums releasing. Sometimes even driving the front wheel drive vehicles on pavement can free up locked rear drum brakes.

At my house I have a tow strap, a pick up truck, and a teenage assistant to help with these maneuvers!

Good luck and keep us posted.

Paul

 

I am in this situation. It does not make sense to me how would the adjuster help fix the problem. When I engage or disengage the electronic parking break the cable does not move and adjusting it could only release the drum but not fix the problem. Any other suggestions?

 

Correct, because we are not talking about the eBrake (which is not an eBrake in the modern sense of the word), all that happens when you push the P button is that it engages a pawl in the transmission. I would not trust this on its own as a park brake, although many do.

What is being discussed is the parking brake, which is the lever activated by foot and is located to the left of the brake pedal. Alternating the park brake and the foot brake activates the self-adjust mechanism.

 

There are usually sections of the parking brake cable that are Bowden cable: a moving part inside a nonmoving sheath. Where under the car, exposed to the elements, there's usually a rubber boot/bellows at the end of the sheath to keep salty water out of there. If the bellows ever gets cracked or leaky and salty water gets in, such a cable can seize up. It can get so that you can pull it tighter with force from your foot on the pedal, but when you release the pedal, the brake return springs aren't forceful enough to pull the cable back. I've also seen them get bad enough they won't move at all.

I would start by: (a) making sure the pedal is fully released and up. What does the cable then look like where it attaches to the pedal? Has the cable moved as it should with the releasing pedal, and stayed aligned with the connection point? Or has it just bunched up loosely behind where it connects to the pedal, as if the cable itself didn't move when you released it?

If it didn't move, can you get it to move by hooking something on the cable beneath the car in back and pulling like mad?

If the central cable moves nicely (apply and release) with the pedal, do the two cables to the left and right rear brakes do the same? If not, can you free those up?

Or is it that the cables all move freely, but the levers sticking out of the brakes don't move?

For that you'll need the drums off to look inside.