In a "thread" of a few days ago, one of our members had an accident with his EX, which he claims was due to his inability to stop his EX owing to total brake failure.

Before I begin this discussion, let me assure everyone I am not going to deny I have a "MS Degree" ( "Master Of Screwing Up"). If I had a dollar for every time I screwed up or broke something, I wouldn't be chatting with you guys - I'd be on my 240 ft. long luxury yacht off the Greek coast, admiring the hundreds of cute young things whose "attentions" I would have...well..purchased....

So - folks, please dont interpet this discussion as making fun of the guy who damaged his EX.

I am unable to demonstrate total brake failure as reported by the fellow who wrecked his EX. By disconnecting the front brake line, installing a hose so as to divert the fluid into a can, I find the following:

1) takes about a DOZEN "pumps" of the brake pedal to empty the fluid.
2) with the fluid gone from the front half, the brake pedal is a bit lower
BUT WE STILL HAVE FULL BRAKING CONTROL OVER THE REAR WHEELS.
3) With the lower brake pedal, there is still full control and "feel" on the
rear brake, from partial braking to full rear wheel "lock up".
4) While the stopping distance is longer, you still can make pretty
ferocious panic stops using only the rear wheels. (Our EX's, unlike
many other vehicles, have enough weight on the rear wheels to
provide pretty good braking using the rear wheel brakes alone).
5) I am unable to demonstrate total brake failure, since there is plenty
of fluid left in the portion of the master cylinder that "feeds" that
portion of the master cylinder "plunger" that "feeds" the rear brake
lines. Cannot demonstrate any way to 'stave' the rear brakes of
fluid by emptying the FRONT system.

As a side-note, to Ford Motor Co's credit, they refused to adopt hydraulic brakes until 1939, and for good reason. The mechanical brakes used up until that time were pretty much incapable of total brake failure. Obviously, mechanical brake systems were much more costly to produce, given all the mechanical stuff that had to be manufactured and installed. Going to hydraulic brakes saved a fortune in production. Trouble was, you could get TOTAL brake failure in the event of a "cut" hydraulic line. However, that possibility was eliminated in the 1960's, when the entire industry went to separate or "dual master cylinder" systems such as we have in our EX's.

Bottom line - there is apparently more to this fellow's version of his accident than we have so far. But again, dont be hard on this guy; maybe he screwed up, maybe he didnt. i dont have all the facts.

And anyone who thinks THEY are smart enough not to screw up like I have, is just plain full of it.

P.S. - if you want to try your own tests, you will need an OBD II "tool" to re-set your on-board computer. Once your "CHECK BRAKE" light comes on, just merely re-filling your master cylinder won't re-set it... !

 

I assume that you did your test with a full master cylinder but when your brakes wear the level drops as the pistons on the calipers are now further out holding more fluid, so if the brakes were near worn out how full would the master cylinder be?

 

Did you try disconnecting the cable from the brake pedal?

 

Wait a minute.

You did this "test" where? In your driveway?

 

I've been waiting for 6686L's CSI: Brake Failure Investigation

So how fast were you going when you did all this?

Oh that's right you were where? In your driveway?!?

Try your experiment again, this time driving.

Before you start, make sure your brake front left brake line is worn to the point where it unoticeably leaks fluid. (You can use a handheld grinder or knife) Be sure you make about 4-6 stops before attempting this experiment. This will allow some fluid to leak out reducing your ability to stop. Now we can begin:

1. Make sure you're on a busy feeder road alongside a busy freeway on a saturday at 2 or 3 in the afternoon.

2. Make sure you're in the far right hand lane and have something big and dangerous blocking lane ahead of you. (it should be large enough to potentially or actually kill you upon impact, your choice)

3. Make sure you have someone in a minivan or a truck coming out of a nearby driveway that could drive out in front of you increasing the need to stop. Be sure they pay no regard to you, how fast you're going, and how soon you'll be able to stop for them.

4. Make sure plenty of cars are coming in the left hand lane (you don't want to leave yourself a way out)

5. From a dead stop at about 100 maybe 200 ft away from the object accelerate to 45-50 mph and maintiain speed. (make sure you have no way to avoid an accident)

6. At about 50ft. (less if you're feeling adventurous) gently step on the brakes and see if you can still stop. Then slam on your brakes and see if you can stop before you hit the big, dangerous object you chose earlier. (don't hit the big dangerous object, it could kill you)

If you survive, please post back and let us know what happened.

I'm not recommending by any means that you try this, but be my guest if you want to go that far to prove me a liar.

 

NOW THAT"S FUNNY

 

REGARDING : TOTAL BRAKE FAILURE issue

folks - i am not calling anyone a liar - I think I stated, and I will do so again here, that I dont have enough info. to know what went wrong. Bottom line is, as I noted before, I am having trouble with the idea of a TOTAL sudden brake failure on a modern hydraulic brake equipped vehicle.

The fellow who raised the question of worn brake pads lowering the fluid level has a good point that I didn't think of. ( Maybe because I do look at my fluid levels every once in a while..? ). Is it possible to wear the REAR pads off enough to COMPLETELY lower the capacity of the master cyl's resevior to the point of having NO rear brake, without having the fronts wear off first ?

No - I didn't do this test on a crowded freeway, because I dont have access to a crowded freeway. I know where to find crowded freeways. Crowded freeways can be found in any big city. I am about as far away from big cities as I can get ! Like it better that way...!

Oh - the "street" I can do just about any "performance trick' I want..? Well, it's in front of my house. See...I OWN it ! Yup - I live on an isolated ranch in northern arizona - my "street" is my airstrip. It's about a mile long and 100 ft wide. Public cant get in here. Dead end, and my entrance is marked with rather nasty "NO TRESSPASS" sign. So I can ( and occasionaly actually do) get a little crazy having fun on my air-strip.

We "roll" it about every four months, so even tho it is dirt, with the high "clay" content out here, it is pretty hard - gives pretty good braking action, actually, fairly decent braking action even when wet.

No, in answer to the guy's question about brake cables - nope; didnt try disconnecting any cables.

The issue is not whether he SHOULD have thought to stomp on his cable-operated parking brake. He admits he didn't. Would ANY of us been quick-witted enough to do that ?

I have been called a few things in my day - cant recall if anyone EVER called me that smart or quick-witted - maybe I would have, maybe I wouldn't. Are any of your smart a$$es THAT sure you are as smart as me or the poor guy who damaged his EX ?

Anyway, suppose he had, in a panic situation, been quick enough to stomp on his foot-brake. We dont know the speeds, road surface condition, closing distance, etc. And, as a guy pointed out - again, a problem I didn't think of - suppose his maintainence wasn't that thorough as some of us are - and his rear pads were worn WAY down...maybe that mechanically operated foot brake wouldn't have helped him all that much. ? ? ?

 

You have an airstrip in your front yard? Can I come over and play?

Boy how'd I love to live in AZ as far from a city as I could get AND with an airfield out front.

I've had my master cylinder (old Chevy PU) fail to the extent that it wouldn't actuate the brakes. The plunger seal went bad. Once it was all the way to the floor it would actuate the rear brakes as some sort of fail-safe. So I see where you're coming from.

I still don't think the parking brake will stop the truck when moving at road speeds. You should try it out on that airfield.

 

WOW!!! I cant believe we are investigating this....6686L sitting there on your "ranch" you must be bored out of your mind!!!

I know that when my rear break line blew. I flew threw the intersection that I was trying to stop at... I was lucky there was no one in front of me. When I pressed the break petal it went to the floor with a BIG puff of white wet smoke out the rear of the EX. I did have SOME breaking but not near enough to stop me going from 60mph down to 0mph in under 150/175 yards even 200yds. Yes I was towing a trailer but 6686L you are right "I DID NOT LOSE TOTAL BREAKING", but I didn’t have enough breaking ability to stop. I am sure this was the same scenario with toreado_diesel. I say a prayer for your X my friend...

 

Now that right there's funny, I don't care who ya are.

 

Humm some people are never satisfied... Choice Hawaii, middle of God Forsaken Arizona Desert....... Personally Ill take Hawaii ......

 

I lost my rear brake line due to rust and barely had a peddle, no where near enough to stop in a hurry, this was after changing a flat tire in a rain storm, what a bad night.

 

Bad night???... that was a horable night mudman!!! Was your X Ok?? What did you hit???

 

i ran over a big ol chunk of angle iron,brand new firestone too.

 

Considering the X doesn't "stop on a dime" to begin with, reducing to 1/4 braking power, or less, it would keep cruising about as long as it wanted to. I hope it never happens to me. I've lost brakes on cars before and that was a nightmare. I don't want to think about a truck this big without brakes.