Brakes failure

<div class='quotetop'>QUOTE(Don-RI @ Jul 17 2006, 09:10 PM) [snapback]287983[/snapback]</div>

I'm no tech, but obviously it sounds like the pressure is escaping. Why it is intermittent is strange..although I would think that it has some sort of regulator on it, with a pressure value to keep it from exploding if the regulator fails.

Sounds like the pressure regulator is bad, or that pressure release valve is bad causing you this issue.

 

sounds like an actuator- why were they so hesitant to replace it? probably because it's a real *&^!@ PITA.

 

they've got you in a rental, don't they? six days... that's usually not justified except in the most extreme cases or when obscure parts need to be ordered.

well, best of luck Don and let us know if it's fixed.

 

<div class='quotetop'>QUOTE(Don-RI @ Jul 20 2006, 07:06 PM) [snapback]289689[/snapback]</div>

Parking brake is independent of power brake and is friction-based. I don't see why it would be a bad idea to use parking brake whenevr possible.

 

<div class='quotetop'>QUOTE(Don-RI @ Jul 20 2006, 08:06 PM) [snapback]289689[/snapback]</div>

alright, hopefully that takes care of the problem.

when you set the parking brake there is an adjustment of the rear drums, and it is possible for them to be adjusted too tightly. so if you start to hear a squeak you might reduce your use of the parking brake. that's about all.

 

QUOTE: "...my parking brake wasn't doing an adequate job of adjusting the drums"

I believe tha "parking brake" has nothing to do with 'adjusting the drums.' It is simply a cable system to engage the rear brake shoes. Drum-type brakes are generally automatically adjusted when you apply brakes during reverse motion.

 

Sounds like a remaining question may be, how did air get *into* the
system in the first place...
.
Last year I had a pressure sensor go bum in my actuator -- all the
pressure sensors are in there including the ones for master cylinder
pressure. Symptom was that all *four* wheels locked up with the
slighest pressure. Fix was, of course, to replace the actuator
which *is* a PITA and the elaborate dance to bleed the system is
just stunningly complex.
.
_H*

 

<div class='quotetop'>QUOTE(htmlspinnr @ Jul 21 2006, 01:06 PM) [snapback]290007[/snapback]</div>

the self-adjustment system works by simply using the parking brake. all you need to do is use it once a week or so and it should adjust itself sufficiently. no braking in reverse needed. are you using it once a week? and is this your classic or the HSD prius?

when DH has a car in the air, he can tell if the owner uses their parking brake regularly. spin the rear wheel, and pull on the parking brake cable. the wheel should spin free, and it should stop when you grab the cable. that means it's in proper adjustment. if it's not in adjustment, you'll hear the brakes rub when the tire is spinning (too tight) or it won't stop when you pull the cable (too loose).

hope that helps.

 

sigh... you poor guy. whoever you're dealing with really needs to get with the program, i recall this isn't the first time you've gone back to the dealer multiple times for the same problem while they screwed around with your car.

that's gotta be a bad actuator.

(edit: DH, half jokingly, said afterward to go into that dealership, tell them that a tech 1200 miles away knows what the problem is and while they can't see what's right in front of them, they need to put a #($)&^ actuator in your car.)

 

<div class='quotetop'>QUOTE(htmlspinnr @ Jul 21 2006, 10:06 AM) [snapback]290007[/snapback]</div>

Hi Rick, it is very easy to determine if the rear brake shoes are dragging at all. Just stop and feel them about 2 miles down the road. Warm=dragging, cold=not. This test is especially definitive in the NHW20, because it goes to such great lengths to avoid using friction brakes.

 

good to hear, this really does sound like it'll take care of the problem. let us know what happens.