What makes brakes stop working when it's hot outside?
 

When it's between 95-110F outside my brakes go almost completely out... like they are almost all the way to the floor.... I don't think it's the booster, because if it was I'd still have regular not power brakes, right?

Someone told me it could be the master cylinder ... I'm thinking maybe I'm getting some air in the lines .. Or maybe the fluid is old and boiling momentarily.... anyone know what might cause this?

Now the brake pedal goes a lot farther down than it should even when it's cool outside......

It's a 1993 accord

low fluid for sure, either due to water, air, etc. certainly start at the master cylinder.

maybe it's time to replace the break pads

Could be a lot of things like a bad caliper/s, heat expanding something allowing air in the lines, leak in MC, check if paint is missing from the car body since brake fluid leaks strip paint, brakes might need bleeding, etc.
I'd have a mechanic look at it.

The pads and rotors are new..
I added some fluid, it wasn't very low though... how do you get air out of it? Take the lid off and pump the brakes? Or do you have to actually bleed the whole thing???

Two things, it sounds like you have water in the lines, which when hot will cause a soft pedal feel.

And if it is that then you have a leak, more then likely in the master cylinder.

If the fluid is low, means you might have a slow leak. They have to be purged of air bubbles. Since you have new pads and rotors, master cylinder and lines , calipers and wheel cylinders are left. I would bleed the brake lines first

I would definetly get professional assistance when working on something like your brakes. But if you feel comfortable working on them, bleeding is fairly simple, but it takes 2 people. You have one guy undo the break line as you press it down, then he tights it back up, while your still holding it down. When tight, you let off and repeat.

Popular Mechanics has a how-to on this subject.

it can be a weak line that expands when you pump the pedal, if the pedal goes all the way to the floor you can pretty much rule that out though. but if it only happens when hot then you have a leak and something got in the system that reacts to heat more than hydraulic fluid, again, prolly water.
you'll have to bleed the brakes if so, no biggie.

you can *maybe* pump the brakes with the master cylinder cover off to see if any water rises to the top, then it can evaporate.

don't smash the pedal when you do that, you'll blow all the fluid out the top of the master. slowly.....

you can feel each hydraulic line going to each wheel to see if it's a weak link.

Isn't it your employer's car?

If not, then it is probably related to the breathalyzer lock thing you had installed :thumbsup

;p

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:1orglaugh:1orglaugh:1orglaugh

:1orglaugh:1orglaugh:1orglaugh


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you know it's about as funny as it can get when all L-pink can do is giggle!

hahahahahah

:1orglaugh I was going to give a serious answer until I saw the post and was reminded he shouldn't be driving at all.

Anyway, On real hot days, less heat is able to escape from under the hood. Extra heat in the master cylinder can cause the internal bore to slightly expand. If the cup seal inside the bore is worn the bore expands from the heat and the seal starts to allow the brake fluid to by-pass it and the brakes become softer than that big spot on JohnnyClips head.


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brake fluid boiling and/or friction lost between pad/rotor due to excessive heat. completely flushing and refilling your braking system with new fluid will help immensely. some aftermarket pads and rotors are made to withstand heat a bit better, and though completely unnecessary for a street car, stainless steel lines have been shown to help with pedal feel and travel.

I wouldn't be driving that shit around town. Bleed all of your lines. If it happens again I'd start looking 4 leaks in the lines or cracks in the master cylinder.

i never take brakes my wife beats me :( help

I would consult with your lawnmower.

Conversation around 2am tomorrow somewhere in Kansas:

"Officer I didn't wreck because I'm drunk again. I wrecked because my brakes don't work. If you don't believe me go fuck yourself and look for my post"


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oh yah huh. the seal can detoriate if there's consistently low brake fluid right?

And probably being original on a car that qualifies for antique license plates.


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I am impressed :thumbsup


btw, see sig.

;p

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In a previous life I operated then sold my tire/auto repair stores to Sears. Now I don't even fill my own windshield washer reservoir.


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Thanks for the comedy and the good ideas

fuck you assholes i was crying 4 help

It means you will die in a horrible rear ender and the estate gets sued unless you take the car to a brake specialist and not GFY

Wow! This thread delivers....is this for real?????

Rippley's believe it or not!

how can you drive if you have a dui?

shit car maybe?

:2 cents:

'93 Accord is old old old and as L-Pink has mentioned, if the master is original still, then there is a very good chance that it is the problem. ESPECIALLY if you find your foot hitting the firewall when you brake on hot days.

Just had a quick look on ebay and an accord m/c is cheap as over there $50 or there abouts, for the price, i'd just replace the thing.

You have to keep in mind 1993 models are already 20 years old.

Around here we call'em "bingo cars" - used by white trash, chronic welfare bums to shuttle back and forth to the bingo hall.

Easily identifiable by all the stupid and banal bumper stickers, empty Big Gulp cups on the dash, and troll dolls dangling from the rearview mirror. :1orglaugh

I don't have any bumper stickers or big gulp cups and I haven't played bingo in years

http://verkoren.files.wordpress.com/...-for-bingo.jpg


Pumping the brakes with the cap off of the reservoir doesn't do anything.. the fluid barely moves, no air bubbles ...even if I jam down on the pedal.. I am pretty sure the master cylinder must be about shot.

i enjoy shitting in my car... :2 cents:

What causes breaks to stop working when it's hot outside is likely the heat.

Well the pedal just goes pretty far down all of the time, even at night, now.. I'm pretty sure it has to be the master cylinder. With the car running- jamming the pedal down hard should make fluid gush out of the reservoir? It definitely didn't. . .

I'll bleed the system first and get it up in the air and look for leaks, first.

This guy I know will slop a used one on there for me for $20, too
It's from a low mileage car but will it be any good? I would think the seals and diaphragm or whatever else in there would be shot...

Are these difficult to disassemble? It seems stupid to slop a whole new one on there when it probably just needs a seal or whatever else.

PS: No one I ask seems to have a clear answer for this... My thinking is that if this were caused by the booster, I'd only lose power brakes, and I'd have a hard pedal / manual braking ... right?

I knew I wasn't imagining that shit
http://www.hondaaccordforum.com/foru...es-floor-4261/

NOW......... If the brake pedal GOES TO FLOOR INTERMITTENTLY ..............You need to replace the BRAKE MASTER CYLINDER .......it leaks internally and you will not see any fluid drop anywhere and fluid will not get low ........

IF it has an internal leak and when a shop looks at it they cannot find any leaks,, it will act up worse on HOT days and during the hottest part of the day,,,,,,,,,it might work ok in the early mornings and in the evenings,,,,,,,,,,
It is very very dangerous the way it is, because if you were to need to make a panic stop and there is nothing there, you could get in an accident hurting yourself, your loved ones or other people in different car or pedestrians ..

So your brakes are not working? Sorry, I cut the lines!

You cut the lines, eh?
And my car is too old, and it's a lowlife type of vehicle, etc etc

You all talk like you've never been poor, before.
Everyone is just a billionaire.. heh :P

For the record, I was never a dick to poor people when ever I have had a little money. I'm not sure what people get out of looking to insult or belittle others, but I think it's a waste of time.

Okay, I am down, I have been down for a long time, ha ha ha ... real funny .. I've never taken $1 from the government and I've half supported several of my loved ones who were supposed to be elders..

Hard times, all that,

At least I am trying now
Relax with the insults- they don't bother me
The funny ones though, I love those, good work on those :D

:1orglaugh:1orglaugh:1orglaugh - I was going to just say, "alcohol."

As I have said 1000 times-

I am always the first one to leave my car and walk if I have been drinking. I have put complete strangers into a cab to keep them from driving. I don't condone drunk driving. I wasn't drunk when I was charged with DUI.


Some things are only funny until they happen to you