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Discussion Starter #1 (Edited)
I have done a disc brake conversion on my 1963 Galaxie as shown on this thread.
http://www.fordmuscleforums.com/braking-articles/510822-galaxie-front-disc-brake-conversion.html

I am having a problem with bleeding the front calipers.
I did the 2 man bleeding job, fired up the car, drove it up and down the street a couple of times, and then came home disappointed.
We then thought about it and started bleeding again.
There is a problem when bleeding the front brakes, but I can't figure out why.

I am using a clear plastic tube from the bleeder nipple into a jar.
We can pump and bleed 3, 4 or 5 times with no air, but then we get a stream of bubbles. So we did it again and again with the same thing happening.
Then I noticed with the nipple closed off, a stream of bubbles started running out. What the?
So is the nipple sealing all the time? It was closed off very tight.
So we go to the other side and the same thing happens after a little while, with the bleeder nipple tight.

Why on Earth are bubbles streaming down the clear tube when both the nipples are tight?
Is it a coincidence for some reason that both bleeder nipples may be faulty?
 

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(OK, I'll pull a DanH here) :D :D

Hint: If bubbles are moving DOWNWARD in a line of fluid that is NOT moving, then you are not seeing what is really happening.

Fill a tube with fluid, and introduce air. the bubbles will go UP not down....

So please, don't use being at the bottom of the earth as an excuse for bubbles to travel upward, and explain again what is happening AFTER THE BLEEDER IS CLOSED.
 

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Discussion Starter #4
That was the first thing I checked Dan, and the hose was tight. (the real DanH that is, and not the fake DanH) :)
 

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I had this problem with my Merc. when I re-did the brakes and lines.

Air is trapped at the top of the Front calipers..

Pull them off (one at a time)

Open the bleeder and compress the pistons in, then close the bleeder
and reinstall or SLOWLY push the brake pedal to push the piston(s) back
to normal and then reinstall.

I don't think you can put them on backwards, but the bleeders should be at the top/back side..

DanH is right (IMO)..you might think it's tight, but that's what the cause is...

Good Luck
 

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To avoid sucking air into the bleeder threads (which can look like a poor bleed), grease them up. Put a 1-way check valve on the end of your bleeder tube, crack your bleeder open, and just smoothly pump away - no close/open routine. Use a long tube so you can see it from the driver's seat.

To avoid causing micro bubbles that are harder to purge, pump smoothly at 3 to 4 seconds for each up or down stroke. Keep the reservoir full manually, or by punching a 3/16 to 1/4" hole in the cap seal and inverting the bottle on the res so it will auto-fill as you use fluid. I will rubber-band a couple sticks to the bottle to keep it in-place, or Qwik-clamp a stick to the res and band to that. One-man deal, slick and quick and easy. An alternative is one-man vacuum bleeding under the car with no pedal pumping.

Silly question - you did verify the bleeder is not only up, but at the highest point of the caliper bore? Sometimes, with calipers used on a different application, the actual opening in the bore is not exactly at the very top in the new setup. In this case, use a compression block to bleed them off the mount at whatever angle works, then install and drive. Also, it's important to bed the brake pads and rotors properly. Don't make a final judgment until that is done, as it can make a difference in stopping power.

David
 

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Discussion Starter #8 (Edited)
Lucky I took lots of photos.
Yes, as can be seen, the bleeders are right at the top of the calipers.



I'll be doing some more checks of the system and taking the advice. I'll also look again at the tightness of the bleeder hose on the nipple.

I have another question which I have been thinking about.
Look at the comparison between the original single pot and the new monstrous master cylinder.



I am wondering with what I presume that the push rod might have to travel deeper into the master cylinder compared to the old original one. So my question is, does the piston sit flush with the circlip at the back of the master cylinder, or can it be depressed somewhat further down the bore so that it will end up traveling deeper when the brake pedal is pushed? I'm thinking it should be flush with the circlip.

Also, the firewall bracket in the photo isn't used.
 

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This doesn't answer your question but will you clarify something for me? Are the tubes from the master to the valve 1/4"? and then at some point down to 3/16" at the brakes themselves?

If you can get ahold of some speed bleeders it might ease the suffering. I got some because I have many bleeds ahead of me but for you they might be a waste of $20 if this will be your last bleed for a long time.. They are not as good as their reputation but they ain't bad.
 

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Hey Dan, good evening mate.

Pushrod!

Ensure that your brake pushrod touches the MC plunger when your pedal is up and at rest with no downward pressure.

Verify that your pedal design can depress your MC plunger a minimum of 2 inches of travel.

NO, you may not start the process by having the plunger depressed a small portion of the way simply due to the difference in design of the two Masters.

You need to lengthen your pushrod if you cannot get at least 2 inches of travel.

Your brake pedal should have adjustments for more UPWARD travel movement which you may have to adjust to be able to use a longer pushrod. (you may mod your pushrod by welding a bolt to the end of it...)
 

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Discussion Starter #11
Puttster, go to the disc brake conversion thread. It tells you there what the brake tubing is. Front tube from master cylinder is 3/16 all the way. The rear is 1/4 out to the valve, then 1/4 to the brake switch, then 3/16 for the rest.

Gary, the pedal at rest is just touching the plunger, using the adjustable push rod that comes with the kit. Also, the brake pedal is all the way up, touching the upper rubber stop.

I'll hopefully be getting hold of a vacuum bleeder in the next couple of days.

But having thought about it all, I'm now thinking that it is probably bled correctly. I'll have to look closely at where the bubbles came from, probably around the plastic hose connected to the nipple.
But I think the non stopping problem might be because I need to bed the brakes in, after what PSIG said. Because I remember when I replaced the pads on my Ute some time back, it wouldn't stop at all until I clocked up some miles, a similar feeling to what these brakes feel like.
 

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I have done a disc brake conversion on my 1963 Galaxie as shown on this thread.
http://www.fordmuscleforums.com/braking-articles/510822-galaxie-front-disc-brake-conversion.html

I am having a problem with bleeding the front calipers.
I did the 2 man bleeding job, fired up the car, drove it up and down the street a couple of times, and then came home disappointed.
We then thought about it and started bleeding again.
There is a problem when bleeding the front brakes, but I can't figure out why.

I am using a clear plastic tube from the bleeder nipple into a jar.
We can pump and bleed 3, 4 or 5 times with no air, but then we get a stream of bubbles. So we did it again and again with the same thing happening.
Then I noticed with the nipple closed off, a stream of bubbles started running out. What the?
So is the nipple sealing all the time? It was closed off very tight.
So we go to the other side and the same thing happens after a little while, with the bleeder nipple tight.

Why on Earth are bubbles streaming down the clear tube when both the nipples are tight?
Is it a coincidence for some reason that both bleeder nipples may be faulty?
lets start with why you are dis appointed .

stopping power
spongey pedal
hard but travel to far/floor
other issues
 

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Discussion Starter #14
Yes the master cylinder was bench bled until the piston was at the point where it was almost impossible to push.

Dan, car felt unsafe and wouldn't lock up the brakes, with pedal maybe an inch or 1 1/2 inches from the floor. Even when I pumped a few times, it still didn't want to stop too well.
I'm thinking now that there probably wasn't any air in the system, and it might be a simple matter of bedding in the brakes.
I have now borrowed a good vacuum bleeder which I will try tomorrow, but I'm willing to say that I don't reckon any air will show up.
 

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Yes the master cylinder was bench bled until the piston was at the point where it was almost impossible to push.
Something odd there. The bench bleed should allow full stroking of the master with only moderate hand pressure (resistance to pumping). Stroking should have fluid circulate from the res, through the cylinder, out the ports and back into the res, with no bubbles when fully bled. You should be able to stroke it all day if you wanted to (waiting for jokes). When mounted, the pedal should be sprung fully up, just barely trying to touch the rubber bumper. You should feel braking resistance within a couple inches, and a solid pedal within a couple more - maybe 1/2 pedal.
Dan, car felt unsafe and wouldn't lock up the brakes,
While bedding will help, you should be able to lock them up with a solid push. As an example, when I did the disc swap on my Cougar (Granada/Mav manual), we towed it a couple miles on it's first outing to the exhaust guy with a 3/4 ton Suburban and tow strap. With the Sub for all the go-power and also holding light power to keep the strap tight during stops, the Cougar provided all the braking for both vehicles without a problem, even without bedding. Yes, it took some pedal effort to stop them both, but nothing my wife couldn't do. Would you say your setup could do that as well?
with pedal maybe an inch or 1 1/2 inches from the floor. Even when I pumped a few times, it still didn't want to stop too well.
The pedal is way too low. Indication is air or short-stroking from excess leverage ratio, though short-stroking should give you yet more power. I'd throw a brake pressure gauge on it to see what's going on at all four corners. Are you using the stock pedal with the pushrod pin in the stock location? It's a factory manual setup, right? Did the pedal gain stroke when you pumped it?

David
 

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Still sounds like air in the front calipers...

Drive it slowly on sand and lock-up the brakes ( or try to)

If it shows the rear brakes locking and the fronts just roll..then it's air in the top of the front calipers...

OK...I'm done...

Good Luck
 

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I bleed my m/c via plugging the outlet ports then plunging. I do this with the m/c installed on the car.
 

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I was wondering about that as I was bench bleeding like a p*ssie. Put MC in a vice, plug outlet ports, pump 20 times. Or put MC in car, connect outlet ports to system, pump 20 times. What's the diff?
 

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Don't let the mc run dry when bleeding or air will get back into the system.
 
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