Why don't we ever see something like this anymore? http://www.thedefianceproject.com/single-master-lifegaurd.pdf
I think most modern, late model systems will warn you if the fluid runs low. If I recall correctly my old VW rabbit had a float or something in the cap. What I what to know is why no one has a valve that would shut off fluid to a wheel if the line or wheel cylinder blows? I remember a few years ago someone came out with a system for racing motorcycles that would keep you from loosing the entire front braking system should one of the lines or calipers go. It was based on some some of check valve used on propane tanks. This would be a great improvement for guys running single master systems
DING DING DING! also, like any idiot light, they are for idiots! only tells you after it's too late. your foot will know instantly if there is a leak oh, and for the record, a booster isn't necessary when you upgrade to a dual master cylinder.
Shutting off hydraulic pressure to one wheel cylinder would cause the car to brake unevenly. If it happened to be one of the front brakes, the car would want to swerve and possibly causing an accident. The dual master cylinder allows either front or rear brakes to continue to operate if there is a leak in one of the two systems. If the proposed check valves* were installed so that either the front two brakes or the rear two brakes were shut off in the event of a leak, the result would be the same as a dual master cylinder. * "check valve" actually being a flow fuse.
The proportioning valve only controls the pressure of the system. They're used to help balance the application of the front and rear brakes.
This topic begs me to ask...when do you typically loose a brake component??? If you're like me - it's when you get yourself into a panic situation and STAB that pedal HARDER than you normally do. It is at THAT moment you oc***ionally find that the lines somewhere were thin and reward your lack of preventative maintence by blowing out on you. And when I say "you" - I mean ME!!!! Of course if it was as simple as just an oc***ional lookie see - we'd all probably be ok, but there's so many other places to fail - what's a fella to do??? Well I've leanred that the WORST time to evaluate brake system condition is in an EMERGENCY!!!! Nope - now every once in a while I go out and wood the **** out of the pedal while my car is in PARK. Let it blow in the driveway - not going 80 miles an hour in traffic!!!! That's my story and I'm stickin' to it!!!!
Oh! Well O.K. then Mr. Rocket Scientist! Tell me why than when a hydralic component fails the RED light comes on the dash on most cars? Dosn`t that light connect to the proportion valve switch? Have you never tried to bleed brakes, and have no fluid come out? Don`t you know that when pressure is lost on a circuit that the valve slids over to DISCONNECT that circuit so you dont lose all your braking? Haven`t you noticed that most newer cars have only a single resevoir for fluid? Being a mechanic for the last 30+ years and doing this **** for a living I guess dosn`t hold a candle to your expertise!
I guess that it has been clarified! I was just looking through old magazines last night and came across that article. Thought it was interesting and it got me thinking about one questionable cylinder on my wagon project.
Actually, it's Ms Rocket Scientist! I didn't spend six years in Rocket Science School to be called Mister ! You didn't specify a factory set-up. My mind reading skills are not that well developed, yet. But, I honestly do not think the valve you are refering to performs the function of a flow fuse. I know the shuttle inside will actuate the switch in the event of a pressure differential between the two delivery sides. But, that will only be an indication to the driver via the dash light. The master cylinder would bleed down on the side that has had the failure. The other side will continue to deliver pressure to the unaffected two wheel cylinders. I never challenged your 30 years of experience and expertise. I only corrected what I thought was an error in the interpretation of the function of a specified valve.
OH, I`m sorry about that. Always nice to see a lady on board! The switch on the propotion valve will only trigger once the valve piston has moved to one side, therefore shutting fluid of to the other side! Oh, by the way beautiful Merc! Who built it?
ok, i got a 93 taurus, broke brake line in back,fixed the line, now i can,t bleed the back brakes,ford garage wants 75.00 to hook up computer to open the valve that,s shut. is there anyway i can by past the ***puter? its got abs disc,s. in the back.tia bob
The switch that turns the red light on on your dash is called a PRESSURE DIFFERENTIAL SWITCH. It tells you that one side of the brake system(front or back) has lost pressure.
I`m well aware of this! Did you read the post above yours? The reason that lone wolf cant get fluid out of the rear wheel cylinders in because of the proportion valve has slid over!
There yankin you dude! The ABS on that car has nothing to do with your problem! Open ALL of your bleeders front & rear than push the pedal down to the floor & hold it there till you tighten the bleeder`s. That will center your valve. Then SLOWLY push the pedal back down 1/2 way with the rear bleeders open & repeat as needed till fluid comes out. DO NOT push the pedal all the way down again until you get fluid, or you will slide the valve over again! Short strokes to avoid too much pressure. This WILL work as I do this for a living everyday!
I was referring to your question. "Dosn't that light connect to the proportion valve switch?" I was not referring to any ABS system.
thanks alot, i,ll trie what you said.i hate new cars.i love working on the old stuff, new stuff isn,t nothing but junk too me. bob
Wow, an actual rocket scientist. Do you use the phrase, "it's not rocket science" much? I would use it all the time. Thank you for the correct technical term, flow fuse, I like it and I can actually understand what it means, as its ****ogous to an electrical fuse, shutting off the flow in the event of a fluid "short". The car would brake unevenly? Well, whichever way it swerved I still wouldn't have hit that step van, bent the front of my wagon, and gotten a bill for $1000. Losing the brakes to one wheel is better than losing all braking when the light turns red. A post mortem on the brakes revealed the aftermarket new rubber line to be two inches two long and rubbing on the inner edge of the drum occasionally, eventually leading to a blow-out. Braided stainless steel lines are a vast improvement, but they can still fail. As for why not switch to a dual master, well, I am. It's on the list of things to do. But what if you wanted your firewall to look original? No dual master cylinder I know of looks as cool as the old single "Jelly Jar" type. They all have that pressed cap with a wire bail holding them on. I suppose a clever person could make a remote resevior master cylinder with a fabricated iron "Jar" mounted to the top. Anyway, I'm just brainstorming. I swapped the original booster in my 60 Chevy for one from a 62. Mounts to the firewall the same, but can mount a later master cylinder with no problem.
Just a side note not totally off topic. I was driveing the Pusher today and noticed that the brakes didn't feel Normal, as if anything in the PknBners world is normal. Anyway I checked the brake fluid the next time I stopped and sure as the sunrise it was low. Guess it helps to pay attention and probably its easier to notice in one you drive everyday, but there is a lot to be said for checking your fluid levels once in awhile. BTW my e brake works, does yours?
Last time I tried to bleed my disc/drum suburban I couldnt get the damn valve to pop back. So I got the guy at Monro to do it. I got him a window and a piece of stainless for his '57 Chevy wagon, so he didn't charge me. But it's only $20 normally anyhow. Saves a lot of frustration - they can use a one-man setup to bleed them and no screwing around trying to trip the valve and all that. Why can't you run a proportion valve on a single master system that just cuts off one end or the other when there is a leak? (probably because you'd have to build it). Not easy to add a dual under the floor of a '50 CHevy.
Interesting. Don't you own that car?? If it's junk, why not get a different car, maybe something in the "older" category?? If it's the wife's, have HER figure out how to fix it!! As to the "Lifeguard" item: It's a simple bandaid, made to fix the problem in the owner's mind, rather than any actual "problem". If there were a leak, this item would not help in the least, as any leak in a single master system bleeds pressure from ALL the brakes, leaving NOT ONE with any pressure. More fluid ain't gonna help that!! But, it FEELS like you did something... Cosmo
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