= =

you are right. I am not a fan of using a mechanical means to try and operate disc brakes. As you point out, it just dosnt seem to produce useable braking action at speed.

You are missing the point mentioning this guy's failure to use his PARKING brake. This guy admit he didnt try his mechanical/parking brake. Hell, are you that sure you would have the presence of mind to think about it. Not sure i would. I am not sure i would be that smart or quick-thinking. Dosnt matter. The issue i am concerned with, is the question of total brake failure on a dual HYDRAULIC brake system. That really troubles me. Not because i want to pick on someone else's misfortune, but for my own peace of mind. When pulling my 10,000 lb. Plus car trailer, not a problem - have electric brakes that would work just fine even if the ex had no brakes whatsoever.

But what about my big boat? Its trailer has surge brakes. Unless i have some kind of positive brake action on the tow vehicle, i would have no trailer brakes. Not funny to think what total brake failure would mean, when you have a ocean going motor yacht AND its heavy three axle trailer, that if you hit something, would wind up sitting on your lap...!

 

6686L,
You are correct about the Excursion having a DUAL MASTER CYLINDER.
This being a seperate reservior for the rear brakes and the a seperate reservior for the front brakes.
This being said one would only loose either the front brakes or the rear brakes according to which line was open. But as designed not both at once.
I agree in theory with your post, because you have posted about how a DUAL MASTER CYLINDER works.
As for how easy it is to stop with half of the system inoperative I don't know, but there should be some stopping power.


Where the airstrip idealogy came in I don't know, it seems only a way to creat more and more nonsense. Just ingore it, happens all the time.

Some people take CONTEX from CONTENT and don't know the difference. Maybe we should start reporting posts that are nonsense.

 

= = = = = = = =

Thanks for your "post". If I understand you correctly, you are argreeing with what I have discovered - but not sure what you are trying to say about me using my air-strip as a test course.

? ? ?

If you are telling me that my using my air-strip to test out my questions about stopping power using only the rear wheels, is "nonsence"? Or are you just making fun of the guys who think it was. ?

Not clear why anyone would think that is nonsence. I sure as HELL would not go out on a public road for partial brake test experiments, where I can't control who or what might dart out in front of me.

Hope you arent suggesting that the issue about partial brake failure I am raising is nonsence. At least, it isnt nonsence to me. It is a potentially DEADLY SERIOUS issue.

If there is some defect in FoMoCo's master cylinder design, by which BOTH front AND rear hydraulic systems can fail at once (assuming normal routine maintainence and inspections - ( you guys DO look at your fluid levels once in a while, I hope, and you DO know you are supposed to check the fluid level on that plastic "tank" on top of your brake master cylinder....) we need to know that. This isn't supposed to happen. Perhaps the guy who started this "thread" has the potential of one of the greatest "product liability" law-suit issues since Ford decided it would be fun to make up the Pinto to be a crematorium in the event of a "rear-ender".....?

As I noted in previous posts, in my own case, since my primary use of my EX is to tow VERY heavy loads, and my boat trailer has "surge" brakes, it is a deadly serious matter that I have confidence in the "back-up" capability of a dual master cylinder.

Help me out on this, you guys - can you help me understand all this better...? From what I have discovered so far, I THINK I am safe - absent gross lack of maintainence COMBINED with no inspections of fluid levels, I am

1) unable to come up with a scenario of losing BOTH of the independantly "plumbed" front and rear hydraulic brake systems on my Ford Ex.

2) satisfied that in the event of a total catastrophic failure of my FRONT hydraulic system, the rear HYDRAULIC brakes give me plenty of controllable braking power.

 

6686L,
I am agreeing with you 100%.
An airstrip would be a very good place to test this situation.
It would be nonsense to try this on the public road.
As you stated the EXCURSION has a DUAL MASTERCYLINDER.

As you stated disconnecting the front brakes should not affect the rear brakes. But it will affect the overall braking of the truck.

It was late last night when I made the post and I suppose I used a wrong choice of words. I supposed I made a confusing post, not meaning to.

To make a long story short, I am in 100% in agreement with your post and the idealogy you used.

When the thread first appeared I had the very same thoughts you have expressed.

 

SHAME ON YOU - ANYONE WHO AGREES WITH ME 100% MUST BE ALMOST AS CRAZY AS I AM !

 

On the serious side the only thing that I don't understand on the dual master cylinder deal is:
If one part of the system (front brakes) or (rear brakes) are out of fluid.
Does the anti-lock function work?
The question I will ask you did the brakes pulsate when you applied the brakes with the front brakes disconnected.

The reason I ask this question I also have a Chevy Truck 4x4 and when it is in 4 wheel drive is engauged the anti-lock system is disconnected by design as stated in the owners manual.

 

Yeah, Urban...what are you trying to say?


6686L, I had an old Chevy 6.2L K2500. The second part of the master cylinder (the part farthest away from the driver) was for the rear brakes. Even though the seal on the plunger couldn't push fluid to actuate the front brakes, the design was such that the tip of the plunger would still actuate the rear brakes when pushed through the MC that far.

Wasn't smooth, couldn't modulate the brakes. It was a sudden lock up of the rear brakes.

 

= = = = = = = = =
GOOD QUESTION. NOPE, REAR HYDRAULIC BRAKE WORKED JUST FINE. NOW YOU HAVE ME WONDERING. ONCE, WHEN RUNNING UN-LOADED, I DID HAVE TO MAKE A PANIC STOP . MUST HAVE SLIPPED MY MIND THAT THIS THING HAS AN 'ANTI LOCK' SYSTEM. THAT IS, IF IT DOES?

HASNT EVER 'TRIGGERED'. My OBD II dosnt show any malfunction ? ? ?

 

Just scanned a few of the Excursion Brake Failure posts minutes after my daughter was backing down our driveway and the pedal went to the floor, zero braking and the Check Gauges light came on. For her age she reacted pretty quick and turned the truck off. and at that speed it stopped fairly quickly. When turning the truck back on it was fine. No brake line damage, no fluid leakage, nothing else visibly wrong that I can tell so far. Obviously a bit nervous about letting her out in it until I get the brakes checked, but I have been driving it daily and there have been no signs of wear yet.

Is there mechanical connection between the pedal and the master cylinder? Just wonder if the computer could create such a failure. The pedal adjust making me wonder just what the extend of the variability lies in the electrical system.

 

I did a "test" of my own last May in Albuquerque, NM. I had a loaded 9500# car trailer behind my X and had a minivan cut me off at an intersection and then spike her brakes. When I hit the brakes, I felt something go pop and I had a TOTAL LOSS OF BRAKING including my car trailer and the brake pedal went completely to the floor. I continually pumped the brakes which gave very limited braking but it took me over a block to get the rig stopped.

Regarding the parking brake, I would surely have jack-knifed the rig as it was on a steep downgrade where she cut me off. I was able to swerve to miss her and then had to pass through an intersection against the signal and thankfully didn't hit anyone.

The trailer brakes which are controlled by a Prodigy P3 never came on because the unit never sensed deceleration of the tow vehicle. In my panic, my hands were locked to the steering wheel while I avoided traffic and I never thought to use the manual brake control until after I got stopped and I did use the trailer brakes to get to a repair shop.

The failure occurred in a flex section of line between the master cylinder and the antilock unit. The Excursion had relatively new disk brakes and pads so excessive displacement of the caliper pistons did not play a part.

After repair of the brake line, everything was tested and the brakes were working properly on all four wheels.

Yes, I know about redundant braking systems and always felt that 1/2 of the brakes would work in the event of a hydraulic failure. I thank God that no one was hurt when I learned first-hand that this isn't always the case.

 

I think I'd immediately replace the master cylinder. It sounds like there could be an intermittent failure of the seals on the master cylinder piston.

 

FARFUGNUGEN!!!!!!!!!!!!!!!!!!!!!!!!!!!!

 

Stainless brakes line should be standard on all vehicles!