View Full Version : Scary brake issue
01-15-2013, 07:20 PM
From the start:
Parked my 4runner friday afternoon after driving home in some slush. Didn't drive it all weekend.
Monday morn. going to work at 5:30 a.m., stops fine at first stop sign on way out of neighborhood. Second stop sign pedal doesn't compress and no brakes!(almost) Luckily I was going slow! And actually used the e-brake for its intended purpose. So I figure the parking brake froze. Cycled the e-brake a couple of times, and pumped the pedal until it compressed. Brakes worked fine after that, and all afternoon.
This morning, the same thing, but the pedal was really hard to get any movement. This time, the pedal released really fast. Then kinda spongy and fine after that, and again this afternoon.
Fozen shut e-brake? Moisture in brake fluid? Frozen open caliper? These are my guesses based on the cold ass temps and recent snow, and the combination of the two is the problem. All the brake components are relatively new as well, so I hope it's not mechanical.
01-15-2013, 07:53 PM
Brake booster freezing up (or rather the check valve). My wife's Corolla did the same thing a few times first thing in the morning. Once you pump the brakes a few times (before you get on the road) and the engine gets a little heat it should be fine. If you want to fix it get a new check valve.
01-15-2013, 08:28 PM
Luckily I was going slow! And actually used the e-brake for its intended purpose. So I figure the parking brake froze. Cycled the e-brake a couple of times, and pumped the pedal until it compressed. Brakes worked fine after that, and all afternoon.
do you have an extra non factory brake? many people use e-brake and parking brake interchangably when they are essentially the same (parking brake was used early on because it didn't do much more than hold a rig while parking, not sure if it's industry or not, but they began to be called e-brakes or emergency brakes later on). if the park/ebrake didn't work, it wouldn't have worked in your "intended purpose" episode.
if you're calling your actual brakes the ebrake, then i would expect moisture in the system...time for a complete flush and new fluid.
01-15-2013, 10:00 PM
Yeah, could be as simple as old brake fluid, which has taken on more moisture and is freezing. If you can get it somewhere warm enough to bleed, that my be enough to make it act normally again when it's cold out. My '96 runner did this, and new brake fluid fixed it... heck I rode in that truck this past weekend (now my brother's).
01-16-2013, 08:23 AM
I have seen frozen brakes in my '95 LC and '94 4Runner and determined that it was the booster check valve or some booster part that had frozen. It only happened when very cold and I don't think it was fluid related. YMMV - I might still use this as an excuse to bleed the brakes!
01-16-2013, 10:24 AM
Go ahead and bleed them and change the fluid. Probably past time anyway. If (when) it happens the next time it gets cold, a brake booster check valve will fix it and is cheap to boot (less than $50).
Possible vacuum leak at the booster? Probably would have heard that but with how cold it was those two days, maybe a possibility? I know my 80 has a slight leak when the temps drop really low. Old rubber I guess.
01-16-2013, 05:16 PM
What is recomended interval to change out brake fluid?
01-16-2013, 07:03 PM
Different manufacturers have different recommendations. Once upon a time it was an annual affair. These days I think it's more like every 3 years. Back in the day the systems weren't sealed as well as they are now, so essentially change it as often between once a year and once every three years as you feel your system is sealed. Not too well/older parts/older system, etc. change it more often. The better condition everything is (and more modern), you can probably go closer to the three year interval.
01-16-2013, 08:13 PM
Everything was fine this morning. Must have been the cold. Sorry, should keep my terms the same, was calling e-brake/ parking brake the same. Guess nothing wants to work at 5:30 in the morning when it's arctic cold outside. Thanks
01-17-2013, 05:49 PM
X4 on the suggestion to bleed the system thoroughly, although I doubt that was the root cause, based on the description of symptoms I tend to agree that it might be a booster issue.
01-19-2013, 09:55 AM
I will bleed everything as well as just a good old flush. As soon as we get home from the hospital from having our baby girl:eek:
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