I have never had the car off of jack stands. Rebuilt all 4 calipers, pedal cluster & installed a fresh 17mm MC and 4 new flex brake lines. Set the venting clearance on the rear brakes and the pedal clearance is also good.

Bleeding the brakes I get good fluid movement and no air bubbles from all 4 corners. Probably have been around the car 10 times now. The last 2 times around were the best as far as no air and lots of fluid per pump...using my wife to press the pedal.

Rear brakes grab and hold. I cannot move them by hand.

Front brakes now grab, but with just a bit of extra work I can move the rotor with my wife holding the brake pedal down.

My pedal is not firm and does bottom out. Then if the key is on, the dash warning light flashes at the bottom. Is that how it works?

the main question here:
But why do I still have a weak pedal and little or no front brakes? Do I just need to get it moving and operate the brakes?

Thanks,

Clark

Clark because yours is a 75 it should have dual bleeders on it. Dumb question I know but did you bleed from both?

Mine seemed to trap air it it some how unles you did both.

Before I set the pedal and the venting correctly I was bleeding both. Jerry recommended just the top, so for the past couple of rounds it has just been the top. I will make another round and do both this afternoon.

Clark

Another dumb question but I have let air back in at times when bleeding the open valve way. Do you use a hose one the bleeder and insert the other end in a clear jar of fluid? I thought I was done many times only to have this method show more air.

Yes, Barely crack the bleeder, and use a 1/2 full jar. Only way air can get in is by the threads of the bleeder.

I also made a few rounds using the tire valve on the fluid res. cap. I could not watch the bleedings, so I went back to ask the wife to work the pedal.

for afternoon brake experts to chime in!

Since the front calipers are self adjusting, wouldn't a short slow drive back and forth in front of the house start that process?

Or a better question... How does that work?

I had a similar issue and here's what I figured out. . the bleeder itself can let air back into the caliper thru the loose threads when you crack it open. .I was trying to use a Mity-Vac and it was just sucking in more air. . . Had a buddy come over and did them the old way, but still some issues. . .I finally got them bled by just cracking the bleeder and closing it before the pedal got all the way down. Still, it took many times around to finally get all the air out. . . . I was starting with a bone dry system and it took about a dozen times around. .
Also, make sure the person in the car understands "Pump em up" and "Hold it down", Start with the right rear, left rear, then right front and finally drivers front. . Pedal should be rock hard with moderate pedal pressure. . lots of pressure and you may feel the rear compensating valve working. but it should still have a firm pedal.

maybe we have some evening brake experts.

I have been around the car 2 more times with the compressed air method on the res cap. Did a few extra times on both front calipers. Tonight I have been using both bleeders on each caliper.

Also have been one more time around with the wife using the pedal. I am seeing no air when I bleed, yet the pedal goes to the floor.

Again, I spin the rear by hand and ask her to brake, and it stops quickly and I cannot move the rotor. The front stops, but if she holds the brake and I can turn the rotor with both hands.... it slips.

I see no progress on continued bleeding. I get great flow with each pump of the pedal.

I'm no brake expert, but I did spend the night at a Holiday Inn.

Do not drive the car with a brake pedal going to the floor, that would be asking for trouble. Is your wife wearing high heels while pushing the pedal?

to address the air passing the threads on the bleeder, I have packed a bit of plumber's putty (Play-Doh) when the threads are cracked loose. Remove it after all is bled. Also, try to have the area at base of the bleeder screw to be dry so the plumber putty can adhere (this can be accomplished by spraying brake cleaner). I also own a Motiv brand pressure bleeder, the type that applies positive pressure at the master cylinder on top of the brake fluid.

Bleed the Master Cylinder?

perhaps you have a small leak somewhere else in the system. New flex lines, master cylinder? All connections tight?

I would check the fluid level in reservoir, pump the pedal hard several times and recheck the fluid level. see if it is dropping. Seek your leak if it is.

The light is not blinking all the time. I read a few posts and that is what I got from them. Is that what you are thinking? It only blinks, maybe every third or fourth pedal to the floor.

I also read that the reset button is on MC switches with 2 wires. Mine has one.

I have heard of seals within the master cylinder failing and causing something similar but the fluid would have to go somewhere. If it is not losing fluid then it has to be air?

If you don't get some more reasonable answers email Eric at PMP.

Yes new everything but the hard lines. I see no fluid at any connection. Not in the tunnel, around the MC, the pressure thing in the engine compartment, calipers, no leaks or wet-ness.

my thought too. The E-brake cables are not on yet. E-brake levers at the calipers work. I checked that when I did the venting.

Isn't it the Holiday Inn Express that makes you smarter?

Sorry about ND.... Not a Michigan fan either, ever since that stealing the Heisman from Peyton thing.

Still in a shell shock phase from that game

Did you check the floor under the MC, behind the pedal board?

No pedal board installed yet. But yes I crawled in under there and looked and felt. No fluid there either.

With a new master cylinder you won't damage it with full piston movement that occors when pumping the pedal to the floor, because there are no places in the cylinder that would damage the piston seals through full stroke.

This of course only applies to a known new master cylinder.

WARNING about OLD-NEW parts: If I had had the confidence to dismantle my "been sitting on the shelf a while, still in the box" NEW master cylinder, I might have found this:

Click to view attachment

Click to view attachment

it is the MC section that pressurizes the FRONT BRAKES. You know the ones that I spent 10 days dicking around with. Once I got it out, I really did not see anything. But once I touched it, it felt hard. I squeezed a bit and it cracked between my fingers.

This is a 17 mm MC, so none of these innards are available? Would love to hear that there really are some seals available.

Rat Farts! You just can't win with new old parts sometimes! I bet Eric a PMB Wwould have the seals.

nice find

Love the new avatar. Make it go faster!

I found my receipt for the MC and have emailed they business. IIRC they were cleaning out the parts bins. He may have been selling the business. Maybe the new owner will show me some love! But they are in Devon PA, so I can't say I'll be frequenting their establishment very often.

Clark

No seals available.

I'd just throw a new 19 in there and lick your wounds. It sounded like your front circuit wasn't bleeding out properly. Now we know why.

Word of caution on MCs. The internal seals don't have ozonates or enough ozonates. They do not like sitting for long periods of time w/o fluid.

Clark what else do you need to put away your jack stands for a while? You of all people deserve a drive and soon! I am willing to make a trip up to help out if you want. You deserve a break. If there is something I can help with let me know.

His journey has been long but light can be seen at the end of the tunnel. He's the type of person that would check the CHT when asked.

Clark....After all we went through on that front circuit, this is what I was afraid you would find........How do the rest of the rubber parts in that MC look...or feel?