We were traveling on i81 near Roanoke VA in heavy stop and go traffic, on a very hot day, and decided to pull off to fuel up at a nearby Pilot. Brakes were fine up until we pulled up to pump to refuel. After refueling, we started to drive away when I felt the brake pedal go all the way to the floor. Luckily I was able to apply the e-brake and got the rig stopped. No dash lights came on to indicate any brake trouble, and a check of the brake fluid reservoir showed it full and no leaks. At this point, we called GS Roadside Assist for help (completely useless I might add, but that's another story), and after many calls back and forth the final outcome was that we were going to have to spend the weekend boondocked at this Pilot filling station. We settled in for the night, but after dark I thought I would give the brakes another check and found them to be working again. Back on the road, we completed our journey without further incident. Will have the rig into service tomorrow to have everything checked out, but wondering what could have caused this problem? Anyone have any similar experience or idea as to what could have caused this?

I'm sure someone knows what you drive, maybe they would have a better idea what the problem might be.

2004 Coachman 28' C on Ford E450 chassis with the V10 eng.

I'm going to guess master cylinder.

If the brake pedal and bracket, along with the linkage to the master cylinder are still attached correctly, the only way the pedal can travel to the floor is if there is a failed seal in the master cylinder or an opening in the system to let brake fluid out. If the fluid level remains the same, the master cylinder is the culprit.

If it's the master cylinder, then would it be normal for the brakes to "recharge" like they did?

Brakes - No Brakes | Good Sam Community

wcjeep
Explorer
Jul 14, 2014
Have your mechanic check the brake pads. They might have liquefied. The "stop and go" in hot weather would do it. After stopping for fuel your brakes no longer had air flow. When the pads cooled later they seem to work. This is partially true. You are now due for all new pads all the way around regardless of mileage or age. You may be due for new rotors/drums. Have your trusted mechanic inspect. When the pads cooled they crystallized. They can no longer be trusted for an emergency stop.

This is an advantage of diesel exhaust brake. The engine brake does most/all of the work during normal operation. This leaves the pads/caliper/rotor cool for maximum effect during an emergency.

As mentioned earlier, the brake fluid could also be bad. While brake fluid does not compress, the contaminants inside the fluid do compress. If you did liquefy the brake pads include a complete brake fluid flush. This entire repair will be expensive.

Again, have your certified mechanic inspect before leaving again. Do you have an infrared temperature gun? Did you take any readings?
hmknightnc
Explorer
Jul 14, 2014
TX77705 wrote:
2004 Coachman 28' C on Ford E450 chassis with the V10 eng.

10 year old now contaminated brake fluid would be my guess as well. I drain, flush and completely replace brake fluid on all my tow vehicles every 3 years just for this reason.
rockhillmanor
Explorer II
Jul 14, 2014
2004 Coachman 28' C on Ford E450 chassis with the V10 eng.

BRAKE LINES

I came off a ramp after driving for 4 hours and had no brakes! Yup you do see you life flash before your eyes!

Collapsed Brake lines are a very common problem and ALWAYS overlooked by repair. The lines will look perfectly ok from the 'outside'.

BUT

They collapse on the 'inside'.

It can come an go until the fatal day you don't manage to stop. It's an accident waiting to happen if your mechanic is not knowledgeable about truck brake lines.

I managed to get to a semi truck repair shop that day and had new ones put on.

I did have to stay overnight because there are no aftermarket brake lines for the Ford E-450. I had to wait for the OEM parts to be delivered. I certainly did NOT have a problem waiting for them!

I recommend anyone buying a used MH to just go ahead and have the brake lines replace. IMHO a Small maintenance price to pay when you life is at hand.:C
naturist
Nomad
Jul 14, 2014
This is just a wild guess on my part, but it was hot out today. Sitting at the pump, engine off, for 5 or 10 minutes, gives things under the hood plenty of time to get as hot as the engine, since there's no cooling air coming through the grill.

If it has been a long time since you had the brake fluid flushed and replaced, it is possible that the heat boiled it, which would give you no hydraulics. Brake fluid is notoriously attractive to moisture, and the effect of moisture in it is to lower the boiling point. Many auto makers, particularly those that make sports cars, but others as well, call for brake fluid flush, bleed, and fill every couple years. Volkswagen and BMW among them. It's just part of the routine maintenance.

If this was indeed what happened to you, you are fortunate that it didn't happen while you were going down some long steep hill somewhere.

But, as others have noted, there are other possible causes, too. All of which should be checked out. We want you to be safe out there.
Community Alumni
Jul 14, 2014
Perhaps the brake fluid got too hot for some reason and it caused some vaporizing which can cause the pedal to go down since you are essentially pushing vapor and not fluid. This happens to us in racing on occasion.

Did you ever change the brake fluid or add fluid with a rating that had less heat resistance? You might want to have the brake fluid changed if you are sure there were no leaks anywhere within the system?
TX77705
Explorer
Jul 14, 2014
If it's the master cylinder, then would it be normal for the brakes to "recharge" like they did?
westend
Explorer
Jul 14, 2014
If the brake pedal and bracket, along with the linkage to the master cylinder are still attached correctly, the only way the pedal can travel to the floor is if there is a failed seal in the master cylinder or an opening in the system to let brake fluid out. If the fluid level remains the same, the master cylinder is the culprit.
K_Charles
Explorer
Jul 14, 2014
I'm going to guess master cylinder.
TX77705
Explorer
Jul 14, 2014
2004 Coachman 28' C on Ford E450 chassis with the V10 eng.
K_Charles
Explorer
Jul 14, 2014
I'm sure someone knows what you drive, maybe they would have a better idea what the problem might be.

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