No Brakes W/Out Engine Running?? WTH??

[reelamin]

Recently I had my first ever break down with my Toyota. Literally I have had problems but never actually broke down. Was out in the hills hunting and blew a radiator. Luckily it was down hill for a few miles to a main road. I found out my brakes were only good for a couple applications then they faded quickly. They faded so bad no matter how hard I pushed it would not slow the rig down enough to keep me on the road. (old logging/fire road)

This was a first for me as I have always been able to still have brakes on Fords, Chevy, Dodge cars and PU's. Sure I had to press hard, but I have enough brake to come to a stop as needed. NO WAY was it happening in my 96 Runner. Sure I just cranked it over and I had brakes quickly, but it was deffinately different. If I had a major engine issue (where I could not turn it over and or start it quickly) I would have been in a world of trouble had my e brake not been able to stop me. Of course I know now, but holy I was seriously lucky!!

So WTH is wrong with Toyota at least not letting you override the brakes? Did I miss something...highly likely. Steering was normal pressure against a pump.

 

[JayRolla]

Recently I had my first ever break down with my Toyota. Literally I have had problems but never actually broke down. Was out in the hills hunting and blew a radiator. Luckily it was down hill for a few miles to a main road. I found out my brakes were only good for a couple applications then they faded quickly. They faded so bad no matter how hard I pushed it would not slow the rig down enough to keep me on the road. (old logging/fire road)

This was a first for me as I have always been able to still have brakes on Fords, Chevy, Dodge cars and PU's. Sure I had to press hard, but I have enough brake to come to a stop as needed. NO WAY was it happening in my 96 Runner. Sure I just cranked it over and I had brakes quickly, but it was deffinately different. If I had a major engine issue (where I could not turn it over and or start it quickly) I would have been in a world of trouble had my e brake not been able to stop me. Of course I know now, but holy I was seriously lucky!!

So WTH is wrong with Toyota at least not letting you override the brakes? Did I miss something...highly likely. Steering was normal pressure against a pump.

I bet your brake booster is failing.

 

[catrains]

nothing wrong with booster................
your problem is because the brake fluid needs replacing. when you start this project you check the brake calipers for sticking pistons or just replace the front calipers.

if you have rear drum brake replace the drums esp if the shoes are wearing un even.................

 

[mtbtim]

I bet your brake booster is failing.

Does a 96 have a brake booster? I thought the boosters were only on the 01 and 02 models.

 

[JayRolla]

Does a 96 have a brake booster? I thought the boosters were only on the 01 and 02 models.

If has a booster but no hydro assist. I thought almost all vehicles have some type of booster. That's the big thing the master cylinder is connected too.

 

[mtbtim]

If has a booster but no hydro assist. I thought almost all vehicles have some type of booster. That's the big thing the master cylinder is connected too.

Gotcha, makes sense. I was just remembering when bleeding the brakes for [MENTION=102606]infamousRNR[/MENTION] 2002 and most recently [MENTION=98597]Jayjayb96[/MENTION] 2002 that you have to have the key in the "on" position to power up the brake booster when bleeding the brakes. The brake boosters on those years are different than the 96-00 models from what I understand. So, is the difference with the 01 and 02 models that they have a hydro assist?

 

[diverscale]

I bet your brake booster is failing.

the problem is not related to the booster since since you'll have no booster anyway once the vacuum reserve is out when the engine is off, and this is what the OP is telling.

I bet there is a underlying problem with your brake system as you should be able to brake even without the booster, with much more force application. I'd begin by inspecting the front discs and calipers.

 

[JayRolla]

the problem is not related to the booster since since you'll have no booster anyway once the vacuum reserve is out when the engine is off, and this is what the OP is telling.

I bet there is a underlying problem with your brake system as you should be able to brake even without the booster, with much more force application. I'd begin by inspecting the front discs and calipers.

How did I let that go past my brain. If car is off booster is not working anyways. Haha. My bad.

 

[mtbtim]

Did you try pumping the brakes to get some pressure when you were coasting down the hill? I just read up on this and supposedly you will have some assist from the vacuum booster for a few brake applications and then you'll be without any power brake assistance. When I had my 68 Bronco, yeah, I could coast all day and have just as good of braking when the motor was on because I didn't have power brakes. I've experienced the brake pedal feel when a car with power brakes stalls and it's not good. I know you were in a shitty situation but maybe the better call would have been to just walk out of there to the main road and call for a tow truck.

Now, with those American Motors vehicles, were you asking as much from them as you were from the 4runner when the engine was off and you had to brake? I sort of think coasting down a hill for a few miles with the engine off when your vehicle has power brakes might be asking a little much of the vehicle.

 

[JayRolla]

Did you try pumping the brakes to get some pressure when you were coasting down the hill? I just read up on this and supposedly you will have some assist from the vacuum booster for a few brake applications and then you'll be without any power brake assistance. When I had my 68 Bronco, yeah, I could coast all day and have just as good of braking when the motor was on because I didn't have power brakes. I've experienced the brake pedal feel when a car with power brakes stalls and it's not good. I know you were in a shitty situation but maybe the better call would have been to just walk out of there to the main road and call for a tow truck.

Now, with those American Motors vehicles, were you asking as much from them as you were from the 4runner when the engine was off and you had to brake? I sort of think coasting down a hill for a few miles with the engine off when your vehicle has power brakes might be asking a little much of the vehicle.

This is very true. No power assist coupled with brake fade from heat could be what the OP experienced.

 

[Tyler James Inc]

Sounds like you're plenty familiar with using normally-assisted-brakes manually, and this is beyond that.
I'm wondering if the fluid has gotten sludge or debris in it somehow, and it is nearly impossible to flow without the booster assisting it? I think I would start with flushing the brake fluid, and seeing if that has any affect.
Also, I think there is a little confusion with the term "fading" here. Brake "fade" is typically referring to overheating rotors/pads, causing the loss of stopping friction. When you said your brakes were fading, you simply meant you lost the ability to stop, right? You weren't going fast enough to cause them to overheat, correct? Just want to make sure we're all on the same page here. It takes quite a bit of intense braking to cause brakes to fade from excessive heat.

 

[kolelt]

I mean, if you stall on a uphill ... you will start rolling .... even if your foot is on brakes. Why?

 

[Tyler James Inc]

I mean, if you stall on a uphill ... you will start rolling .... even if your foot is on brakes. Why?

This should not happen at all...

 

[kolelt]

This should not happen at all...

interesting, because when i was offroading and going up a hill, with obstacles and stalled. It started rolling back FAST, i tried pressing the brake, but nothing really happened!

Why do people say if its going to stall, let it stall in gear?

my brakes are good, all calipers, brake booster, new fluid. Could it have been bad worn out brake pads?

I just replaced new pads, so i wonder how it will be

 

[Tyler James Inc]

interesting, because when i was offroading and going up a hill, with obstacles and stalled. It started rolling back FAST, i tried pressing the brake, but nothing really happened!



Why do people say if its going to stall, let it stall in gear?



my brakes are good, all calipers, brake booster, new fluid. Could it have been bad worn out brake pads?



I just replaced new pads, so i wonder how it will be

I guess I've never had that happen in my 4Runner, so I can't say mine wouldn't do that. It just seems very wrong for any car to have the brakes COMPLETELY useless with the engine off. I've been in a car or two rolling with the engine off, and using the brakes without the booster was definitely tougher, but they definitely worked.
Now I'm real curious if mine would do the same.

 

[phattyduck]

You got 3 applications of boosted brakes with the engine off - this is about the max you could possibly expect.

I think you are underestimating how much boost the booster provides...

Downhill, no boost on brakes designed to be boosted = trouble.

-Charlie

 

[kolelt]

I guess I've never had that happen in my 4Runner, so I can't say mine wouldn't do that. It just seems very wrong for any car to have the brakes COMPLETELY useless with the engine off. I've been in a car or two rolling with the engine off, and using the brakes without the booster was definitely tougher, but they definitely worked.
Now I'm real curious if mine would do the same.

I can guarantee that if you have manual and stall going up hill, especially in woods when off roading. The truck will probably roll backwards even with foot on the brake.

I'm pretty sure it's normal. That's why they say. Stall in gear. So the gear will keep you from rolling back.

 

[reelamin]

Sounds like you're plenty familiar with using normally-assisted-brakes manually, and this is beyond that.
I'm wondering if the fluid has gotten sludge or debris in it somehow, and it is nearly impossible to flow without the booster assisting it? I think I would start with flushing the brake fluid, and seeing if that has any affect.
Also, I think there is a little confusion with the term "fading" here. Brake "fade" is typically referring to overheating rotors/pads, causing the loss of stopping friction. When you said your brakes were fading, you simply meant you lost the ability to stop, right? You weren't going fast enough to cause them to overheat, correct? Just want to make sure we're all on the same page here. It takes quite a bit of intense braking to cause brakes to fade from excessive heat.

Yes the brakes were not fading in application/braking power....the ability to apply pressure to the pads was fading/decreasing to the point of not being able to stop the vehicle no matter how hard I pushed.

Brake fluid is not perfect...but I empty and refill the reservoir every oil change.

 

[reelamin]

You got 3 applications of boosted brakes with the engine off - this is about the max you could possibly expect.

I think you are underestimating how much boost the booster provides...

Downhill, no boost on brakes designed to be boosted = trouble.

-Charlie

I understand the boost goes quickly and expect it the very first application after motor is off. The difference is that all other vehicles I have driven in similar situations the brakes could be applied and even lock the tires. It just required extra pedal effort. No matter how hard I pushed they would not stop the rig. Again, this was a first for me so wondering why this time.

 

[reelamin]

Did you try pumping the brakes to get some pressure when you were coasting down the hill? I just read up on this and supposedly you will have some assist from the vacuum booster for a few brake applications and then you'll be without any power brake assistance. When I had my 68 Bronco, yeah, I could coast all day and have just as good of braking when the motor was on because I didn't have power brakes. I've experienced the brake pedal feel when a car with power brakes stalls and it's not good. I know you were in a shitty situation but maybe the better call would have been to just walk out of there to the main road and call for a tow truck.

Now, with those American Motors vehicles, were you asking as much from them as you were from the 4runner when the engine was off and you had to brake? I sort of think coasting down a hill for a few miles with the engine off when your vehicle has power brakes might be asking a little much of the vehicle.

As others have already covered the first part. I have asked a heck of a lot more for braking from other vehicles in situations with no running motor with no issue. Had I not had a good E Brake./ability to start/crank motor..I would probably be alive...but the Runner would be in the bottom of a canyon 100's of feet down.