Model A is finally done! but I get air in the rear brake lines. I've asked around and most say if they take on air they also leak fluid, well they don't!! Called Speedway's Tech, they insist that I've never got the air out. "You guys have to learn how to bleed brakes!" Well after about 50 times in 5 years i'm getting good at it!! changed: left wheel cyl. 3 of 6 brake lines proporitoning valve added a residual valve brake lite switch all kinds of br*** fittings now speedways ford master cyl. I even brought it to a mechanic, "wow nice job! you should have a leak, but you don't" he said you must have the propotioning valve to close to the x-aust, well it dosent get hot!!! and its 5 inches away!! so the question is CAN I PREASURE THE SYSTEM TO FORCE A LEAK? next spring start at master and redo every thing again???
Does this mean you lose the pedal after a few days? If the master wasn't bench bled, do that first. If you don't get a good pedal at all try tightening all connections again. Raise just the rear and try bleeding them.
Yes lose pedel on 2nd mastercyl no change even used a vise grips, now all powder coat and paint F d up only need bleed rears
What type of proportioning valve do you have? Just in case (just asking), are you starting your bleed from the p***enger rear wheel?
The problem is flowing enough fluid fast enough to get the bubbles out without them back flowing. If you aren't doing it right, you will have to bleed your brakes many times to get the air out. One way to do it is to have a big vacuum reservoir connected to a vacuum pump. You will need to have a way to keep the master cylinder full, but you really gotta get that fluid moving. You can easily fab a system using a pest sprayer tank, some pipe fittings, and a small vacuum pump like the kind you purge an airconditioning system with. A hand pump can be used too, but this will make your hand sore.
I started w/ the purple speedway prop. valve now i have a new Wilwood. always bleed furtherst from master. I've learned many ways to bleed, the best seems to be open master, and open bleeder just so it drips.. mighty vac wife pumping pedal neighbor pumping pedal me on pedal large siringe from vet clinic push fluid in pull fluid out NO thats not how you do it! we always do this! OK try it
I had a similar problem, brakes would air up if it sat for a week. I bled them, then proceeded to kick the s#$t outta the pedal! After some abuse it started leaking fluid down a backing plate, a wheel cylinder was faulty. New, too. You could have a bad res. pressure valve, too.
not to be a jerk, but can you type out your responses a little more. i'm having trouble understanding. you did bench bleed the master? how do you know its only the rears that have air? dual or single master? what exactly did you need the vise grips for?
I've never used them but I sure like the idea of those self bleeders. It sounds like a simple solution to me.
where is your master cylinder located? on some cars the front is the furthest away from the master cylinder, do you have a cual or single reservior master cylinder, you need to give more information
thanks for the help guys! yes more info!! duel master cylinder from speedway, its the ford #910-31420 yes I bench bleed, this time i back filled the master with a siringe, works great!!! the vis-grips was to tighten the conections, most turned another 1/2 turn more than with a line wrench master cylinder on fire wall, so shouldn't need risidual valves!!! any way it made no difference when i added one ( advise from speedway tech) frnt disk brakes have no problem, so the issue is the rear brakes, I bleed out any or many differnt ways, all resulting in great pedal, and brakes!! 200 - 300 miles later i only have front brakes... open the bleeders AIR!! used to farm...... well when you couldn't find the problem, just keep going!!!! you will find the problem as it gets worse. after many years I'm asking for help F d up .. ****ED UP !!!
Yes i wonder if i can preasure the system long enofe for the leak to show. changed out one wheel cyl. thought i could see some " dew " on it. made no difference thanks! keep 'em comming!!
One more suggestion since I don't see it on your list, have you tried 'gravity bleeding' them? By that I mean just open the M/C and crack the bleeders (just the rear in your case, since that's where your problem lies) and let the weight of the fluid push all the air out. Overnight usually does it. I think what's happening is you've got air in the lines that you're compressing instead of actually removing. Eventually it decompresses and you've got a soft pedal again.
Food for thought...let's say your rear wheel cyclinders are ****ing air in when they release pressure. This can happen and is supposed to be avoided by the RPV. So I would question whether or not THAT RPV you have is actually doing it's job. Next the point about not having actually bled it properly to begin with. When you have a high spot in a line it is quite possible to "byp*** the bubble" - meaning the fluid p***es the air bubble without dislodging it. This happens when the fluid movement is SLOW - to combat this you NEED some VOLUME - a pressure bleeder is ideal for this. Next the other possibility is when you MASH the pedal repeatedly (and quickly) you can froth the air in the fluid making bleeding difficult at best. The fix there is to SLOWLY depress the pedal when building up pressure - a heavy foot afterwards is fine!!! Remember those seals seal BETTER with pressure so simply adding pressure to find a leak may very well be doing the opposite - which is one reason I would suspect the rear cups could be ****ing air IN rather than having some telltale leak (out) somewhere. Just a couple ideas - might be worth contemplating.
Try tighting up the rear adjustment on the brake shoes. This will keep the springs from pulling in the wheel cylinders. Sometimes this draws in a little air.
stupid unrelated question... is it possible to have to much pressure? could it cause a line to blow? seal to leak? just wondering...
Can you cap off one side of the rear brakes? Plug the line at the "T" where it branches off to go to both wheels. Then rebleed system and test, just in the driveway pumping the brakes untill the problen happens again. If no problem, redo this test to other side. Or cap off both sides and test, at least this will prove it is the rear wheel cylinders or not. As it was said before, if you end up replacing one wheel cylinder, replace both.
takeing advise and thinking.... so have a stick from the brake pedal to the seat for constant preasure. may be show a leak
I found a leak!! the line into the residual valve was wet with b fluid. I tryed to tighten it ,but to get at it the exhaust has to come off, clutch linkage off. I learned some thing today, I put a stick from the brake to the seat and held preasure on the system for several hours. Now i hope this is it !!! Thanks for your input!!!!!
Thanks for helping me out. This is a picture of my finished A. Seats are to the upholsterer for a red & white tuck n roll, it's done.
Be careful when tightening fittings. Do not over tighten that will deform the double flare on the tubing. I had a leak because the flare was deformed. Inspect the tubing where your leak is. Remake tubing if it is deformed. Good luck..
I had a similar problem, I know you found the leak...so I hope it is fixed. The best thing I ever did was buy a $12 vacuum pump from harbour freight that hooks to my air compressor, that and 4 feet of clear tubing from the Depot and and I can bleed 40ft of 1/4 inch brake line in about 4 secs, the way we gotta do everything by myself!!!!! hook the clear tubing to a GOOD bleeder screw then to the switcher pump($12) lock the pedal to the floor, turn the compressor on, crack the bleeder, when 3 feet of the tubing is full of fluid, home run your done!!!!!!!
sounds like a cool idea thats why i'm here now , looking for a one man way to bleed my brakes does it matter if the adj. prop, valve is up higher than the brakes? just wondering , can you post a picture of your bleeder setup, thanks
Never heard of to much pressure. I had a problem yrs back and found the wheel cyls were in up side down. I was young, and dum LOL
thanks to roughidle's input I use a syringe, the kind they use for livestock. you can either push brake fluid, or pull. never use a mightyvac again! go to a vet clinic buy the biggest one you can find, a foot of hose, and your out only a few $
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