Quadro

I found that 4LO works wonders to break frozen brakes ;-)

SaniDel

I bet! What is amazing is that a powerful vehicle like the GX 460 is immobilized when this happens. So, what actually is happening? I thought that the emergency brake was a '5th' brake on one rear wheel, but not terribly effective ... good for holding the vehicle on a hill when stopped, but not much else. As far as it being used in an emergency if the main brakes fail ... forget it!

Is it possible for a 'frozen' emergency brake to keep a GX grounded? Until I learned to 'dry' the emergency brake on the way home from the car wash I would have to 'rock' the GX as if it were stuck in snow. If that didn't work ... especially in our garage ... I might have tried 4LO!

Could the main brakes be involved ... or do I not understand how the brakes work? Don't worry ... you won't hurt my feelings ... we're here to learn from each other.
Regards,

SaniDel

tecman

I have not experienced this yet on my GX but I have several times on my MDX. I did not have the emergency brake engaged and assumed it was due to an all wheel brake freeze.The gap between the rotors and the pads is small enough to become attached with ice.

Randy B

The Parking brake works on a drum system at the rear wheels. So two shoes per side which cover about 70% of a circle. The shoes are retaining the water and freezing up to the plate assembly that the shoes ride against. The shoes are very thin, not like a traditional drum brake since these are parking brakes and not main brakes.

See the Sewell picture below from a 2014.

Randy B

SaniDel

Thanks for your explanation and the diagram, Randy! Just to be clear ... what you call 'freezing' is not due to cold, but rather to something probably chemical (rust?) between the wet shoes and the plate assembly. Our GX 'sleeps' in a conditioned and insulated garage between two townhouses so it only gets cool or warm, but never close to freezing.
Regards,

SaniDel

tecman

Is it necessary for you to use the emergency brake in your garage? Maybe skip it on car wash day? I only use my brake on a steep hill, otherwise I rarely use it.

SaniDel

No, it is not necessary ... it is just a hard habit to break, but maybe I should.

For fifty years I've been in the habit of putting the transmission in Neutral with my foot on the main brake, which allows the drivetrain to 'unload' then to set the emergency brake and finally to shift into 'Park' for an automatic transmission. With a manual transmission I would leave it in neutral with only the emergency brake to hold it.

My concern is relying on the transmission in Park to hold the vehicle on a sloped surface such as our garage floor and certainly on a hill. It just seems dangerous to have only one 'thing' keeping the vehicle from rolling away. There is a fair amount of 'play' in the GX drivetrain when the transmission is in Park ... it will roll a few inches when you take your foot off main brake before the transmission stops it.

I will probably have to replace the entire emergency brake system at our next service because I am overusing it ... not to mention "dragging the brake" on my way home from the car wash. Maybe that will teach me that using the emergency brake is not always necessary!
Regards,

SaniDel

Quadro

I found that mine freezes whether I engage the parking brake or not. Now I either drive the vehicle after a car wash or, if I had to park right after, walk out to the vehicle 15 minutes later and move it couple feet forward and then back - that breaks ice that's just beginning to form and avoids the issue.

tecman

Ice is out of the equation in the last few posts

Randy B

Sanidel,
I have no clue if its not freezing temps where you park. I thought I had read in the past that this only occurs to you during the winter. That being said, I have not experienced anything like what you have described on any vehicle. However, my ambient temperature does not quite reach low numbers for sustainable hours like yours does.

Either way, now you have an idea of how the parking brake works. Regarding your comment on slack in the drivetrain. I believe if you actually measured the movement of your wheel by using chalk, you would see that the GX barely travels an inch when moved from drive into park and then release of the brake pedal. Even on an incline. Watching the body roll and bounce is much more drastic than the actual wheel turn on the ground. I am not a fan of loading the transmission with pressure (weight) when parking on an incline. I solely use the parking brake when I go to park on an incline and engage it after placing the vehicle in neutral. Upon start, I place the vehicle in reverse or drive and then release the brake. For nominal inclines and or flat spaces, I never use the parking brake.

Randy B

Quadro

All I can tell is my particular issue only happens during winter and only if I park the car right after a car wash. So ice is definitely involved in my case. My case might be different though.

Quadro

Of course you're in Florida... what did you expect :-) For me it only becomes an issue when it gets below -4F (-20C), my theory is the water freezes fast enough before it have a chance to run off the parts.

And yes I had the same issue on other cars too.

Hammer208S

I'll add to my original post. I had washed the truck on a Thursday, pulled it into the garage, and was trying to pull out of the garage on a Saturday when we had this occurence. The parking brake was never applied and the temperatures were well above 70 deg.

SaniDel

This would seem to support the premise that your main brakes are 'sticking' due to close tolerances between the pads and the rotors. Either that or the emergency brake on a new vehicle is adjusted too tight and is 'dragging' slightly so it will stick when wet.

Regardless, it seems the culprit is water ... specifically, parking a wet vehicle without drying the brakes(s). The main brakes probably dry very quickly simply by stopping the vehicle ... momentum is turned into heat, which drys the pads. If I understand correctly, you washed the vehicle, did NOT drive it and returned it to the garage ... presumably with wet brake pads.
Regards,

SaniDel

Hammer208S

We washed the GX on Saturday and left it parked in the garage until today. My wife said when she pulled it out of the garage that it made the loud banging noise after shifting into reverse. It hadn't been driven since being washed 2 days prior. I wonder if the brakes are getting a little corrosion rather quickly.