This morning when I left for work the temp was -4F and as I got to the first stop sign on my drive to work I hit my brakes and got nothing. No braking, no movement of the pedal, nothing. Luckily I was going slow enough to use the parking brake and stop without issue. I sat for a couple minutes and then pumped the brakes pedal and it slowly went back to normal amounts of resistance and movement. Pumped it a few times, released the parking brake and continued my drive with no further issues. Anybody else have this happen to them before? Once the weather warms up I'm going to flush the brake fluid (along with other fluids)

 

I think you're just lucky anything on the car works at -4*. Flushing the brake fluid as soon as you can would probably be a good idea. I can't fathom living somewhere that see's those temps, I'd be miserable. #summerinfeb lol.

 

Complete speculation here but brake fluid absorbs water over time. Is it possible some of this water froze or partially froze and was almost 'blocking' fluid movement ? As the fluid heated up, the frozen parts turned back to water and was more manageable ? Water in brake fluid is normal to some degree.

 

Last week it was -3 F one morning and my clutch pedal would take probably a second to slowly rise back up until the car warmed up. Viscosity of most fluids increases as temperature decreases. Don't worry about it.

 

I've been a mechanic with the Navy 15 years, I know about fluid viscosity in general, just never had it happen with my brakes before, even at this temp.

 

^^^ Then you know way more about this than I do... flushing the fluid will probably help but glad it works now.

 

Also complete speculation, but I'm leaning towards a compromised seal somewhere in the system. But to dispel your theory, brake fluid absorbs water for this exact reason - so that there isn't 'pure' water in the brake line that can freeze/boil independent of the brake fluid.

 

The very first thing I'd do would be to R&R all the brake fluid in the system! Do you even know when the last time your brake fluid was replaced? The reason Nissan recommends replacing brake fluid is because they know it will deteriorate the system causing failure! Lucky s/b your middle name, you got away with brake failure once and survived!
Gary

 

I can almost guarantee this is what happened.

Brakes were hot from driving.

Brakes componenents had a lot of moisture on them from winter conditions.

Moisture froze to a thick icy layer (moreso if it was foggy that night) as the brake components slowly cooled that night.

Brakes were frozen AF next morning.

This is SUPER common on all the heavy equipment at work, normally our operators do a roll check of the brakes on equipment before they actually drive off because frozen brake drums on a front-end loader can end badly when your 30+tons of metal doesn't slow down at the first stop.

If it was thick snow then it could have been packed in around the caliper making it even worse since it would take more time to heat up.

As you applied the brakes everything slowly began to heat up and melt, anything that cold you need +30F just to BEGIN to melt.

 

Well, twice more I've had a solid pedal while warming up, I've just let the engine warm everything up for a few minutes and then it's good to go. As soon as it warms up around here I'll be flushing all the brake fluid, and while at it I'll be doing the power steering fluid as well.