Lost my brakes, pedal to the floor, and used the parking brake

[imorton]

Hi Gang, I wanted to get any help or info regarding losing my brakes this week while in intense stop & go traffic, AND after doing an emergency 40 MPH panic stop.

My 10,000 lb 23ft Class A 1988 Amera Coach (built on a Dodge D350 1 ton frame) lost all it's stopping power this week after doing a "40 MPH panic stop" narrowly stopping 6 inches short of an impact. Luckily I was able to use the parking brake to stop on the shoulder after the incident.

After the panic stop, my brake pedal was very very soft and travelled all the
way to the floor with no stopping power.

The scenario was that it was @ 80-90 degrees in Washington, and I was in stop & go traffic for 1/2 hour, and was confronted with an accident OR a panic stop.

When I pulled on the shoulder I noticed there was smoke coming from the driver side front wheel (maybe from the passenger side too, but I only really noticed the driver side)

I called AAA and it took @ 1.5 hours for them to come, and the young AAA driver got under all 4 wheels and said there was no brake fluid anywhere.

The brake fluid reservoir was full and he than asked me to pump the pedal, and it was hard and felt usual. I than started the RV and tried to stop and it felt "normal". He asked me if I was to be towed or just go on my merry way...

He said that I probably just overheated the brake pads and the fluid, and since it had all cooled down, everything should be back to normal.

I drove it back home and all seemed normal, yet I wonder what happened, and if it needs any mechanical work done.. EX: flush the brake fluid, bleed the lines, air or water in the system, etc....?

Any clues or help would be greatly appreciated... IAN...


PS: I had new front pads installed and the discs turned @ 3 months (or 1,500 miles ago).

[az bound]

The best remedy would be to replace the brake fluid. It is probably contaminated with moisture.

[demoon]

The brake fluid needs to be flushed and changed. I know that Ford recommends a fluid with a high "boiling point". (Not sure that is exactly right, but there is high temp brake fluid). That is what they said happened to my 2000 F53 and it is basically overheating in the kind of traffic you were in or long hills. Apparently the fluid will actually foam and cause air pockets - thus the pedal going to the floor.

[George Schweikle]

The brake fluid doesn't "Foam and get air pockets". What happens is that it absorbs moisture. This works fine as a hydraulic fluid until it is overheated, then the moisture turns to steam. A fluid can't be compressed, so will transmit the braking force from the master cylinder to the wheel cylinders or calipers. However, steam is a gas and can be compressed so doesn't transmit the braking force and the brake pedal goes to the floor. This is probably what happened to your rig, but the brakes returned when the steam eventually condensed back to fluid and your brakes returned. You really need to change the brake fluid. This means change completely, not just top off the reservoir.

Originally Posted by az bound

The best remedy would be to replace the brake fluid. It is probably contaminated with moisture.

[Wanabee FTer]

How old is the master brake cylinder?

The master cylinder is mounted in the engine compartment and can overheat in traffic stop and go conditions. When an older/worn master overheats it can "bypass" brake fluid. As the engine compartment and master cylinder cools it will start functioning again.

I would replace the master brake cylinder and flush the brake fluid if you don't know when it was last replaced.

[demoon]

I guess there is a huge difference between "foaming" and steaming - sorry I used the wrong word, but the results and fix are the same. Although this quote sort of seems to interchange the terminology; "Silicone based fluids are known as DOT 5. Silicone is actually compressible, (causing a spongy pedal) which is one of the reasons it isn’t used in production braking systems. It also tends to foam at high pumping rates, which can happen when the ABS system activates. This foaming will create air bubbles in the system – which will cause a spongy brake pedal".

My reason for jumping back in here is to suggest that you try the fluid first. I paid to have the master cylinder replace, paid to have the brake booster replaced, and finally a Freightliner truck shop had the sense to call Ford and get the right answer. Replace the fluid - and they did say - replace it with high temp fluid.

[imorton]

So it seems from the majority of the replies that the best thing to do would be to flush/replace the brake fluid. I guess a 1988 Dodge D350 chassis would use DOT 3 fluid.

If I change the brake fluid, and everything is good, than no point changing the master cylinder or brake booster.

Now I have to read up on how to flush/replace brake fluid...

I will also have to find how much DOT3 fluid to buy to do this.

IAN...

[whem2fish]

easy way to change the fluid. i used a hand held vacuum pump and opening the bleeders just like you would bleed the brakes. now i have a question i dont own a ford but my 1985 chevy i had a front brake line go bad it caused the front brake over heat. maybe someone will chime in on this

[OSP1268]

If you are going to flush and replace your brake fluid, go with a synthetic. It will not absorb moisture.

[JimM68]

Yup. Valvoline DOT4 synthetic.

Access all the bleeder valves, all 4 wheels, and soak em down with PB Blaster. Repeatedly. For Days. Along with some gentle tapping. They are going to be stuck. Use a good 6 point socket, tight fit. Put some pressure on it and tap it. Be gentle and get the all to break loose before you go any further. Don't want to turn a little problem into a big one.

[kenjh]

look at your pads and look for any blueing ..did you lube the sliders on your calipers when you did the brakes ? have you ever replaced the brake calipers??if they were draging ..things over -heat and destroy your breaks ..and check all your brake hose for cracking or swelling .. and the steel line for rust ..your rig is old enough to need a full inspection ..and yes .. you probably have water in the fluid ..it is "supposed " to be flushed ever 5 years .according to the manufacturer .. I bet not one on 100 do that "maintenance here..

[Bilito]

Originally Posted by JimM68

Yup. Valvoline DOT4 synthetic.

Access all the bleeder valves, all 4 wheels, and soak em down with PB Blaster. Repeatedly. For Days. Along with some gentle tapping. They are going to be stuck. Use a good 6 point socket, tight fit. Put some pressure on it and tap it. Be gentle and get the all to break loose before you go any further. Don't want to turn a little problem into a big one.

I agree with the PB blaster but get a proper sized flare nut wrench, it will grip on four sides instead of two and use a steady pressure to break em loose from the calipers, I tried to jerk em loose and rounded most off, than I had to resort to a big vise grip. All my lines were badly rusted, had to replace all 5 of them. Yea 5, one is from the frame to the rear axle and then from there to each rear wheel

[JimM68]

Originally Posted by Bilito

I agree with the PB blaster but get a proper sized flare nut wrench, it will grip on four sides instead of two and use a steady pressure to break em loose from the calipers, I tried to jerk em loose and rounded most off, than I had to resort to a big vise grip. All my lines were badly rusted, had to replace all 5 of them. Yea 5, one is from the frame to the rear axle and then from there to each rear wheel

A six point deep well socket will grip all six sides of the bleeder valves.
Be gentle with em, they usually crack (flush with the top of the caliper) before they round off.

Absolutely a good flare nut wrench is the only tool to use on the brake line fittings themselves, but hopefully you won't need to go there, this time.

[George Schweikle]

Correct, synthetic brake fluid will not absorb moisture, which seems like a great benefit. I think the U.S. military uses synthetic, and that some car museums like it. However, there is some controversy over this product. I have read that any moisture remains as a "pocket" of water in the system; making this specific location much more prone to rust. And, it seems like a pocket of water in a brake system will boil just like absorbed moisture; with the same loss of braking function. It is known to be difficult to bleed, and has a tendency to result in a soft brake pedal. For you NASCAR fans, I have heard that it is forbidden in the race cars. But.... it can't be all bad, since the major suppliers make and promote it's use. This issue may be like Ford vs Chevy, Michelin vs Goodyear, etc.

Originally Posted by OSP1268

If you are going to flush and replace your brake fluid, go with a synthetic. It will not absorb moisture.