Hauling a 1 ton load (yes I know,, it's a 1/2 ton truck) of wood rails on my '92 F150 Supercab back from the mill in Central West Virginia over Route 50. Followed semi going less that 25 mph down 5 miles of 9% grade, braking constantly to avoid running up his tailpipe. At bottom of grade, pulled over for a pit stop of no more than 10 minutes. When I pulled out to get back on road, found brake pedal went all the way to floor..0 brakes. Taking it easy, drove to Ford dealer 10 miles away. By that time, had about 50% pedal back and it stopped fine. He suggested I bleed system, but being on short time crunch, I drove home, regaining full pedal use within next half hour. My questions: What happened to the brakes?
Did they "merely" boil the fluid? Or was some permanent damage done? They seem to work fine now.

Thanks in advance for any help.

 

Kinda had the same thing happen to my 97 yesterday. Was responding to a priority ambulance call and had to use my brakes a lot in order to not runi into people and as i slowed down to pull into our building, the pedal hit the floor and i had almost no brakes.. When i came back from the call i tested them out and they worked fine.. maybe just over hated them?? dunno... but i was on them pretty hard many times during the 5 minutes it took to get to the building.

 

I think the long grade heated up your brakes badly. Then stopping only made it worse since no air was cooling the brakes. I would only have stopped if there was a longer downhill or stopped for a longer period.

The air was from your brake fluid boiling.

 

boiled the fluid and when going down the hill the air got trap in the piston and got airlock in the m/c until it bleed back down slowly so you got the pedal back when it bleed it self off

 

You're lucky you didn't have a wheel-fire when you stopped or a blow-out while you ran.

You should have been in first gear during that down-hill run to avoid toasting your brakes.

Did you happen to notice those emergency run-off ramps that go 1/8 mile into a big sand pit? You're going to find out first-hand what they're used for unless you make an adjustment to your driving technique.

 

It is likely that the brakes have moisture in the fluid. Brake fluid is hydroscopic and absorbs moisture. Of course, moisture in the fluid lowers the boiling point of the fluid. Some fluids are better at maintaining a high boiling point while moisture laden. Castrol LMA dot 4 is generally beter than OEM or generic fluid and it is readily available.

Chris

 

My girlfriend had the same experience, only thing is she didn't slam on the brakes or have them overheat. She drove to work one very snowy morning and when she left 8 hours later her car was basically in a big puddle. She said the water level was at least half way up her tire. She tried to drive and had complete brake failure, the pedal went to the floor, then slowly returned after a few brakes. Could this have been caused by moisture? She took it in and they said, nope, nothing wrong, no leaks, and that was that. So I've been trying to figure this out since.

 

I had my brakes go out back in may but it was due to water I was going through TX on Vacation it was raining hard and was at my exit to stop for the night in Waco got off the Interstate and the service road was flooded when I went to hit my brakes after getting through the flooded mess I had no brakes the next morning they were working fine again.

 

that is what is called brake fade!

What happens is that you get everything so hot that you glaze the pads or shoes and they become ineffective. If it gets really hot and you have not flushed the fluid or not using the proper fluid you can boil it.

Rear drums are NOTORIOUS for brake fade. They suck! You use them more than once in a panic stop within 5 minutes and they are useless, it will be the fronts only stopping you. Really they are there more for an Ebrake than anything used for stopping at any speed.

Solutions:

1. convert to rear disc
2. run DOT4 fluid instead of the manufacturer spec DOT3, and flush the entire system!
3. Get new performance pads and shoes that are rated to work at higher temps

 

Matt90GT:

4. someone to pay for all that stuff !

 

2 and 3 are under $100.

Rear disc is about 500-1000 depending on what you find.

Pretty cheap insurance if you ask me!

 

kind of off-topic, but whatever you do, don't rest your palm on a hot rotor! I've got a nice little scar forming from when I did that on accident last weekend, after the vehicle had been using its brakes repeatedly coming down a mountain. What a dumbass I can be sometimes .

 

Mattadams,

. . . we all can be, sometimes its just takes us longer to admit it . . . like the time I tried to take a hitch-ball off my Cherokee, finally had to use a nutsplitter on the thing . . . only to find out I was trying to turn the nut in the wrong direction!

Maybe we should start a 'dumba$$' forum . . . !

Bob

 

Matt:

Yeah, I guess that's true; that's not a whole heck of a lot to spend considering what you get out of it.