Technical Brake bleeding not working. Still no pedal.

My 64 falcon fx car is damn near ready to go , However....I attempted to bleed the brakes today and no matter what I do the pedal goes to the floor. Not getting any air at the bleeders now straight fluid. Pedal free play is good Will pump right up to good pedal in 2 pumps. As soon as you let off and push it again it goes straight to the floor. New shoes ,wheel cyls., lines , master cyl. Btw I converted to a 2 line system. Using a master cyl for 69 mustang. Non power 4 wheel drum. Which is what my car is. And I've used this set up before with good results. Did I get a junk master cyl? Fluid leaking past piston? Any thoughts are much appreciated. RS59

 

Probably a bad master cylinder.

 

Did you bench bleed the master before installing???

 

X2.....

 

It's been together a few years but I don't remember bench bleeding. I was gonna disconnect my lines at the m/c and bend a couple to go into the fluid and do it on the car. Then hook it all back up and bleed the system again. That's the only thing I know to try before another m/c

 

adjust your brake shoes up tight until the wheels won't turn,bleed brakes.and then adjust shoes to a slight drag

 

Hmmm. Never tried that before.

 

If you didn't adjust the brakes, then the excess play in them will let the pedal go to the floor. Pumping it would let you get some pedal. Without knowing exactly what is new on the car, etc it's just a guess what could be wrong. Another thing to look for is a small leak somewhere, such as a fitting not tightened enough, or an incorrectly made flare or something.

If you're getting fluid out both the front and back, then it's probably not the mc needing to be bled. But it could still be a defective new mc.

 

Running a pressure switch for the brake lights?

 

Adjusting up the shoes makes a big difference in a good pedal, especially on a 4-drum car.

Adjust, bleed then hold the pedal and see if it drops (bypasses).

 

I would take a look at the pushrod adjustment. If the rod is not adjusted to have some freeplay, you could have a situation where the ports in the cylinder are not fully closed when the pedal is at is up or non depressed position. In that condition, any pressure built up by pumping would be quickly bled off.

- EM

 

Yes. Pressure switch. Not finding any leaks. Push rod adjustment seems good. Has a little free play. Thought I had the brakes adjusted for a little drag when I assembled. I always do. However this has been a long drawn out build so I guess I'm assuming. It's easy to forget to do things when you walk away for awhile

 

My car kicked my butt after a front drum to disc swap. I did everything that the fellas are telling you plus...another bigger M/C....bought a power bleeder from Harbor Freight and ran two quarts through the system....added residual valves even though I had never needed them before.....changed out the rear brake hose and switched the feed lines on the M/C. I had the pressure switch mounted vertical instead of horizontal or at a 45* angle. Someone told me it could NOT be mounted vertical and still bleed the air out so I changed that and bled all the lines starting at the M/C and ending at the feeder block and it came in perfect. I did take the pressure switch out of the system and plug the hole and got a great pedal instantly just to check before I moved it. Just throwing that out there. I'm feeling your frustration because I have been doing this for a long time and got humbled real quick.

 

I'll be damned. Never knew that about a pressure switch. When you say vertical do you mean the terminals pointing up or down ? Just wanna make sure I understand thanks

 

Having the terminals pointing up would trap air in the switch, eh?

 

calipers upside down?

 

so, walk us through the exact process that you are using to bleed the brakes

 

I've had great sucess with Gravity bleeding brake systems.
Start with the longest line, probably the right rear wheel cylinder.
Crack the bleeder just enough for it to drip.
Come back in 20 minutes and shut it, then do the Left rear....
Then right front, then Left front...
Did it with an forbidden topic 93VW and the peddle ended up rock solid, best it had
ever been. But, yes, the shoes need to be adjusted up as well.

 

From what I have run into in the past 50+ years of working on brakes quite often the main problem is in the actual process of bleeding brakes and not an equipment problem.

1. Helper pumps brake pedal too fast and actually sucks air into the system.
2. Helper lets off pedal before you have the bleeder tight.
3. you don't check the level in the master cylinder often enough and the fluid level gets low and you get air back in the system.
4, you are using some half baked method that someone down at the spit and whittle club swears works but you have never seen the work on a car in all the years you have known them.
5. "gravity bleeding= see #4. In 50 years of working on cars, being a brake specialist for a few years, teaching mechanics class and reading thousands of rod related magazines and soaking up almost every tech article written between the early 60's I never heard of "gravity bleeding" until guys popped up with it on here a few years ago. It might work if all the lines pretty well go down hill from the master cylinder without any rises from where it runs along the frame to the fitting over the axle.

After my own fights with the same issue on an OT (91 Mini van) where I had swapped the antilock MC setup for a regular MC with a booster off the same year model of van a flare fitting that isn't sealing right can cause the problem you are having but not show a visible fluid leak. You get good solid pedal, then let the rig sit a bit and then a mushy pedal again. I'd go over every line and fitting in the system and see if there is that one that just isn't right. If the air in the lines problem is always on one end of the system your hunt is cut in half.

 

All great advice. My process has always been to adjust brake shoes for slight drag and start farthest from mc. Rr lr rf lf. I do have a line lok in front system. I'm sure it's in correctly however it is mounted higher than mc. Only place I could find to mount it. This may be an issue I really thought the fluid would push air out no matter if line runs across the roof. Maybe not? And thanks for all the replays so far

 

5. "gravity bleeding= see #4. In 50 years of working on cars, being a brake specialist for a few years, teaching mechanics class and reading thousands of rod related magazines and soaking up almost every tech article written between the early 60's I never heard of "gravity bleeding" until guys popped up with it on here a few years ago. It might work if all the lines pretty well go down hill from the master cylinder without any rises from where it runs along the frame to the fitting over the axle.

Doesn't HAVE to be all down hill junior........there's this thing called the "siphon effect"
that makes Gravity Bleeding work...and work well in a lot of cases.
Not that you never hearing of it makes it any less effective.

 

What became of the pressure switch orientation? Sounds to me like there may be a air bubble somewhere. I have also had a problem like that with my old Phaeton. It was a combination of both the pressure switch and I was in too much of a hurry to bench bleed. I know better and fixed the problem.

 

I adjust them for a heavy drag, then back off 7 clicks (or something like that). If you just tighten the adjusters till it starts to drag a little, you might still have it too loose, if things are not perfectly aligned.

 

Air can get trapped in these UP and Overs.
A line across the roof would give you trouble getting it bled of air fully, you'd really have to work at that one. A bleeder in the high spots of the line would help greatly.


the liquid will start to pour over interior bends in the hose /line and leave air pockets behind.

 

I try to systematically eliminate problem areas from the start. First get a couple of block off plugs and screw into the master cylinder where the lines go. Crack slightly and push out air, then tighten. You should have 100% pedal and if not the mc is bad. On a single mc one can block one line at a time using a short nail in each wheel cylinder (old circle track trick) and isolate the problem corner but I don't know if a dual cylinder will lock the pedal with just one line plugged. If not then plugging one would let one know whether it's the front or rear that has a problem. I have an old Wagner bleeder ball that absolutely gives an all fluid column in the lines but I don't know if anyone still makes anything like this.

 

X2

 

I have had good luck using a Motive pressure bleeder. Not sealed like the Wagner ball so you can't leave fluid in it or it will draw water. I made an adapter to fit top of MC with a C clamp to hold it.

http://www.motiveproducts.com/

John

 

Bench bleeding, whether performed on the bench or on the car, always requires the end of the master away from the pedal to be lower than the pedal end, otherwise the trapped air will never be able to get out no matter how long you keep bleeding it. Easily overlooked or misunderstood.
Chris

 

So assuming the MC is level, and already fitted to car, to bleed correctly we need to start by parking on a hill ?

 

You could ,
Most Guys would use a jack to raise the low end of of the car.

When the term "bench bleeding" is used, having the "bench" isn't the important part. However if done on a bench and free of the car several important things automatically happen.


First you can do this alone. You can see the bubbles. The plunger will return to its home position free of pedal adjustment issues. The master can easily be placed level, up or down hill.
Just be mindful of those and the master has no idea where its being bled.

Brake fluid is pretty easy to outsmart. It follows the laws of physics & fluid dynamics, and it obeys its master.
If it appears that its defying any of those, the conditions are not as assumed or the components are faulty.