oldtimer

Took car out of heated garage drove for 5 kms braking numerous times then all of a sudden brake pedal froze. Would not move. Pushed hard still nothing, Push release push release then finally it moved. Happened 3 times today.
-30 C here car parked in heated garage. Any thoughts?
Thanks

04maximas

I work for pep boys as a mechanic. was with them when we were just brakes. you either have a failed brake master cylinder or booster. its possible a failed caliper but 90 percent of the time if it was a caliper the pedal would sink all way to floor. im leaning more to booster however its best to do both the booster and master cylinder at same time. and make sure to do the best brake bleed and flush ya can

04maximas

if ya wanna check the calipers before ya write the booster and master as bad, remove all four calipers off the pads and rotors like your changing the pads, do not remove the hose and compress all 4 calipers, if they go in smoothly and flawlessly there good and master/booster is problem

oldtimer

So I did a booster test as per Nissan and it passed. Vac is also 18".. The fact I cannot move pedal and therefore have no brakes at all makes it seem to be mechanical ie linkage, master cylinder etc.
Being that it happened only 3 times seems to throw that out the window as something binding would be noticeable all the time. Being fluid is old, could a ice plug develop ?
-22C today. took for a drive and no issue??
Any thoughts??
Thanks

MadMax07SL

Those are some very extreme conditions. Could be a lot of things, but that kind of temp wow. That said, If you have very old brake fluid, may have a lot of water accumulation. I'd recommend once it warms up get the brake fluid flushed out and replaced. The brake fluid has a lower freeze rate I'm sure it should be fine even at your mentioned temps. But water in the line, even just a little if it accumulated together (separation) it would frees as a plug as you suggested.

04BlackMaxx

I lost brakes on my 2004 back in 2010, which was complete bull**** for a 6yo car. The 6th gen was a deathtrap.

04maximas

the 6th gen is not a deathtrap. the 6th gen Nissan has one of the highest safety ratings in the usa. I have 177k on mine and the only issue I ever had was the fuel pump gave out and the rear left caliper seized cause it sat for 2 years before I bought it. and I drive on the highway like I do at the track. id check the calipers to see if they compress easy and flush the fluid out