Brake problem when cold

[Alpacamarc]

Ok guys, has anyone had their brakes pretty much give up the ghost on really cold days (like -10 to -40 degrees)? It's like the booster is no longer working and they're completely manual. It takes everything I have pushing on the pedal to make it slow down. It only does it for the first couple stops on really cold days... then I'm assuming it warms up and everything works normally. Fluid level is ok, I'm thinking maybe a valve of some kind is sticking?? A guy at my work said he's taking his 2009 Corolla in for a brake recall that is the exact symptom of what's happening with my truck, he said the recall is for a valve of some sort in the brake system. Cheers!

 

[raydouble]

Year?
I assume it's a 96-99......think in 2000 is when they did away with the vacuum booster...

I have read another post recently about this exact problem here...
99 4Runner no brake boost when really cold ?? - IH8MUD.com

I'm starting to wonder if that is just the way they act when it's that cold...

 

[TC4Rnr]

google "moisture in brake fluid"

I'm pretty sure your brake fluid is pretty old. try to get it flushed professionally, then see how it works.

 

[raydouble]

google "moisture in brake fluid"

I'm pretty sure your brake fluid is pretty old. try to get it flushed professionally, then see how it works.

Well, if that is the case he should be able to open the master cylinder res. in the morning and see ice formation.

 

[TC4Rnr]

Well, if that is the case he should be able to open the master cylinder res. in the morning and see ice formation.

it could be the check valve. assume it's not.

there may not be that may water to form visible ice cubes. common brake fluid is poly glyco based, not oil base, small amount of water can be dissolved in there over time. at normal operating temperature, it works just fine, as the OP stated. but when it gets really cold, i.e. being sit over night, tiny ice crystals can start to form. that, will screw up the fluidity, that can also cause the hard pedal.

fluid flush is just cheap insurance, you gotta do it anyway if it's due for one.

what you can do now is while warming up, pump the brakes repeatedly just to bring up the fluid temp..

 

[Alpacamarc]

Thanks for the tips guys, I'll start with a fluid flush first. Even if it isn't the problem, I might as well do it just as part of regular maintenance.

 

[cwrose]

I look forward to the results. Having driven 6 Toyotas (one of which is a 2002 4runner) on a regular basis in <-40 degree weather, I've never come across such a problem. I've always had trouble getting moving rather than stopping. Damn square tires.