1998 Alpine NO BRAKES

[gmcgene]

Need Recommendation for brake service in Newport Beach, Ca.

After driving in stop and go traffic for a couple of hours yesterday the brakes on my 1998 Alpine 36 failed. The pedal went to the floor- very little resistance or braking power.

Smelled hot brake odor immediately before stopping. Rear wheels were hotter than fronts- but neither felt extremely hot. Didn't check temps but I could touch wheels without burning my hand.

Managed to get into my space Newport Dunes Rv Park without hitting anything.

Brake fluid in the inside reservoir of the master cylinder is liquid like normal- fluid in the outside reservoir is thick like honey.

Front rotors, calipers, and pads were replaced by Henderson's in Grants Pass, Ore. in Jan 2017- about 4500 miles ago.
Rear calipers were inspected and lubricated at that time.

I don't see any evidence of leaking fluid at any wheel.

Any suggestions will be appreciated.

[Kiawah]

I assume you have hydraulic brakes.

Since you say there is fluid in both reservoirs, then I wouldn't suspect a leak, which would have drained the master cylinder and caused no brake situation.

If caliper's stick, then I would expect a very hot drum/rotor, which you didn't have either.

If you had air in the brake line, then that would have your same symptom of no brakes, but then you wouldn't have had brakes for the last 4500 miles.

So I would suspect a leaking master brake cylinder. There's no fluid leak outside, it just leaks from one chamber to the next. This is the device up on the firewall that houses the fluid reservoirs. When you press the brake pedal, it changes that mechanical movement to press hydraulic fluid out the brake lines to the wheel cylinders.

I can't explain the honeylike brake fluid though. I would have thought that when they replaced your front brakes, that they would have at a minimum also bled the rear brakes and changed out all of your old brake fluid.

If you bleed your brakes to get any air out of the line, you should then be able to press hard on the brake pedal and hold it, and the brake pedal not go to the floor. If you are able to press it to the floor, and no fluid is leaking anywhere, then replace the master cylinder.

[wolfe10]

Before spending big bucks, change the brake fluid. Can be done where you are parked.

Old/hydrated brake fluid will boil, even below 300 degrees F-- a temperature that can be reached in the calipers in repeated application in stop and go traffic. Boiling fluid= NO BRAKES.

Sure, it could be a master cylinder, master cylinder pushrod length issue, etc. But even if that is the case, you sure don't want to put viscous, hydrated brake fluid through any new components.

[twinboat]

As stated above, change the brake fluid.

Ford recommends brake fluid change, every 2 years, on Class A motorhome. Its in your service guide.

The fluid collects moisture. Heavy stop and go use, boils the moisture, causing the fluid to expand back to the master cylinder.

The next time you step on the brakes, your squeezing steam, just like air in the lines.

Once it all cools down, everything goes back to normal, until the next time.

I figured this out the same way you did. Luckly, it happened entering a campground, after a hard stop, comming down hill from a highway.

[Old Scout]

1999 Alpines have a bit different brake set up with 2-piston, single calipers on each wheel. However, what sounds like a full brake service back in Jan should have solved any issues inherent with the 2-piston system. Had the same symptoms a couple year ago with my 03 after a few hours of stop/go traffic in high ambient temps--eg, Florida coast road on a Friday afternoon!!!! Regret having to say that at that time, brake fluid hadn't been changed for a while. Brakes worked fine the rest of trip. However, I now flush/change every 2-3 years, regardless of miles. Hard to believe Henderson didn't flush/change the old fluid. If they did, hard to believe moisture has re-entered the system...
Have read elsewhere that the "honey-like" substance in the master reservoir is silicone from the manufacturer's packing and shipping process...

[EngineerMike]

If you have the reservoir w/two caps that setup gives you two reservoirs below a certain level. The baffle between levels has a slit that allows you to fill both from one side, once above the slit the fluid spills over to the 2nd reservoir.
With this design, I believe, each reservoir feeds two wheel positions (one feeds front and the other the rear if I remember my somewhat long ago research on brakes which is not the best bet). DOT req'mts have this setup reported for air brake systems w/a front air & rear air gauge (those w/Avalanches and a very select few Ltd's know this as the Av's came w/air brakes and you could special order a Ltd w/air). This way you are unlikely to suffer an all-brakes-out failure.

To get honey one side only w/the slit baffle, the level has to be below the slit and only one side filled/purged/filled when brakes are bled. Someone who doesn't know the system might make that mistake, or a shop that isn't overly taxed w/ethics might also. Henderson's is knowledgeable overall (quite in fact) but that doesn't mean eveyone there is perfectly clued in. Check your receipt to see what they reported as done in the parts swap, i.e. do they show a 4-wheel brake bleed. Could be they show a front axle bleed only.

2nd possibility- early two cap reservoirs had a full baffle, requiring a dual reservoir bleed.
3rd possibility- I am spouting clueless whackadoodle gibberish.

[Old Scout]

EM--I usually picked #3 on multiple "guess" tests but will give you the benefit of your experience [smile]. Again, I had the same experience several years ago. Fluid reservoir was full, or near full, but age of the fluid was suspect. I did "top-off" the reservoir [added minimal fluid to put level ABOVE the seam in the tank]. Incident has not repeated since--though I now change fluid every 2-3 years!!!!!

[greenmachine]

I'm lost here and have been for awhile, but no one has said anything about the booster pump. If your going down the road and all of a sudden you loose brakes, that would be cause from dirty fluid? I'm asking cause I had a problem when I first got the coach that the brake switch was bad and the paddle went almost to the floor. After I found I had no brake lights I replaced the switch and lord and behold I hear a pump and that increased my brake. So maybe I'm in left field and you guys have been there and done that but doesn't the pump play a part?
Larry and Tammy
2003 38FD Alpine

[twinboat]

The boost pump is in line with the master cylinder. If it fails, the pedal gets real hard but shouldn't be any lower. It will feel that way as you push the pedal and sink into the seat.

Your brake boost pump runs off the power steering pump, the electric is a backup. I hope your not running on it full time.

As to the fluid, as explained, the water it collects, moves down to the hot calipers and boils causing a steam pocket. Fluid does not compress, steam does.

[wolfe10]

Larry,

Now, I am confused.

The hydraulic boost works off the power steering pump (with engine running). Yes, if the engine is not running and you step on the brakes, the electric boost kicks in. But that should never happen while driving.

The "old fluid causing the brake pedal to go to the floor" can easily occur with old/hydrated brake fluid and will happen when the temperature in any caliper reaches the fluid's boiling point. New fluid boils around 500 degrees F. Hydrated brake fluid is not supposed to boil below 258 degrees F (and that is what is on most bottles of brake fluid). BIG difference.

And, unlike the 2003, earlier models did not use the fixed calipers (i.e. 4 piston calipers). They had sliding calipers (i.e. 2 pistons on one side, none on the other). If the caliper slide area is allowed to get rusty/not kept clean and lubed, the caliper can fail to retract from the disk, causing an immediate heat build up.

Yes, very likely his loss of brakes was a combination of hydrated fluid and perhaps a sticking caliper.

Just needs a good brake servicing!

Certainly there can be other causes of his symptoms, but the above maintenance would be needed even if another part has failed.

[greenmachine]

So what your saying when I'm going down the road and press on the brake the booster will not come on. Anytime you press on the brake on this coach the pump comes on. I had to put a diode on the brake wire from my toad to keep any power from back feeding to the brake wire #52 or 54 but I need to know for sure about the pump doesn't run when the coach is running and the brake is pushed inn. Now I have to make sure about all this. When I hooked the toad up we where good but when I turn the turning signal on it was back feeding power on the brake wire. Diode took care of that. Awhile back I had a post on this someone redid the wiring to run a transmission pump on there toad. They had changed all of it. I wanted to put back to the way it should have been. That brings you up to date on this. When I'm setting and motor isn't running I hear the pump run. But it shouldn't when the motor is running, correct. I wear hearing aids and it sounds like a lot **** going on down there.

Thanks
Larry
2003 38Fd Alpine

[twinboat]

The pump should NOT run when the engine is running. The power steering pump supplies the boost pressure to the unit.

The electric motor will only run when the engine is off. It is an emergency assist, during engine stalling or power steering belt breakage.

Google Hydro Max booster for troubleshooting.

[wolfe10]

Larry,

Yes, if your electric boost (behind the master cylinder) comes on while driving, you need to find out why it "thinks" you don't have sufficient hydraulic/boost pressure and turns on the boost pump.

I am assuming your Power Steering works fine, and it is supplied by the same pump. Yes, could be a hydraulic issue, but more likely an electric one.

I have not researched this, but you might start by determining what triggers the electric pump-- may be something as simple as a pressure switch that has failed.

Engineer Mike may have information on how the electric boost pump is triggered.

[Old Scout]

OK--lets clarify what it means for the "boost to be on." Unlike the vacuum boost on most modern car brakes, the hydro-boost is in line with the power steering assembly and the engine fan motor, and uses hydraulic power from the pump on the Cummins to "power" your service brakes. Without the hydraulic boost on, your brake pedal would be very hard to depress. Believe the hydraulic side of the hydo-boost is purely mechanical--no electrical involved. If the Cummins is off, the hydro-boost relies on a 12v internal pump to provide "emergency" boost for the brakes--this function does rely on electrical components to operate. Whether its being powered by Cummins hydraulics or the 12v aux. pump, having the pedal go to the floor is a "down-stream" master cylinder/caliper issue, not the hydro-boost.....
PS--Larry, you aren't confusing the vacuum pump for the HVAC controls with the Hydro-boost aux pump?????