Front calipers not releasing

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DentalDart

DentalDart

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So bleeding the brakes and the front calipers are not releasing.

I started with the rear passenger then drivers rear to passenger front to drivers front.

I have steady streams in the rears but the fronts not so much.

Any ideas why the front calipers won't release the front rotors and why I cant seam to get a stiff pedal?
 
Ps- The rears have a steady bubble free stream of new brake fluid but the fronts dont.
 
Manual brakes, the rear drums shoes dont move much even when pumping the brakes, and not much fluid comes out when I release the bleeder nipple.

The front brakes have a clean bubble free brake fluid come out of them
 
Looks like the proportioning valve inline may not be sealing all the way, because fluid seems to be accumulating right on top

20200217_183055.jpg
 
Is this a new system? New master cylinder?
 
Hi Doc,

Do you have the larger (rearmost resivor) of the master cyl tied to the front disc and the forward smaller resivor to the rear drums?
 
New master cylinder that I bench bled, the larger rear reservoir hooked up to the front brakes and i also took the line off and added a crush washer to where the line from the MC attaches to the prop valve. Bleeding again right now, doesn't seem to be leaking from the prop valve line in from the mc anymore.

It seems like the only line getting any air bubbles out of it is the passenger side front, but not much comes out of the rears and the shoes dont seem to move much

20200217_194040.jpg


20200216_191440.jpg


20200216_191525.jpg
 
Rear shoes not moving much? Are you bleeding and pressing on the brake pedal with the rear drums off?
 
The line above the brake switch in the second photo looks pinched.

IMHO I would bite the bullet and buy new OEM reproduction lines and the year correct distribution block and proportioning valve.

There could still be a lot of trapped air in the lines.even if fluid flows out clear. Think aeration.

Do you know for sure the combo block and proportioning valve is functional?
 
Forgot... If the location you put a crush washer has a standard flare fitting like the rest of the brake system the crush washer is masking a bigger issue.

Remember the brakes are the most important part of your life
 
also. You are going to repair/ replace your stearing cuppler. It looks toast and partway out of itself?
 
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Dana67Dart said:
The line above the brake switch in the second photo looks pinched.

IMHO I would bite the bullet and buy new OEM reproduction lines and the year correct distribution block and proportioning valve.

There could still be a lot of trapped air in the lines.even if fluid flows out clear. Think aeration.

Do you know for sure the combo block and proportioning valve is functional?
Click to expand...

I got the prop valve the other day from a guy here on town he had it on his demo . But said he had to run a washer there for it to not leak. I tried it without and it seemed to leak a little.

Yes all of the lines are the stock lines and have sucked trying to get them on/off of the different prop valve they just want to strip from being so old..
 
Dana67Dart said:
also. You are going to repair/ replace your strating cuppler. It looks toast and partway out of itself?
Click to expand...

Straightening coupler?

You mean my steering coupler? Um... not currently. Have to get this project finished first.
 
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Sometimes, a new master cylinder is not the same as the old. I have had them sometimes make the rod in the back seem too long due to machining tolerances and make the front drag and even lock up. Inspect the rod and see if it needs shortening. I've run across this many times in the aftermarket.
 
RustyRatRod said:
Sometimes, a new master cylinder is not the same as the old. I have had them sometimes make the rod in the back seem too long due to machining tolerances and make the front drag and even lock up. Inspect the rod and see if it needs shortening. I've run across this many times in the aftermarket.
Click to expand...

I used my stock rod from my stock MC, and bought the MC that others on here have used. How would I know if it is to long?

20200126_115011.jpg
 
DentalDart said:
I used my stock rod from my stock MC, and bought the MC that others on here have used. How would I know if it is to long?

View attachment 1715472444
Click to expand...

Unbolt it and see if you can feel the rod engaging the master cylinder piston when you push the master cylinder against the firewall. You may need to get someone to hold the brake pedal in a neutral position inside the car.
 
DentalDart said:
Yes I have been, should the drums be on while bleeding them?
Click to expand...

They absolutely MUST be on if you plan on stepping on the pedal. You can bleed brakes without them, but only with a vacuum or pressure bleeder. If you step on the brake pedal without the drums on you can overextend the wheel cylinders, which sets the bleeding process back to zero. Also, that takes a ton of fluid, which is why you're not getting the calipers working right.
 
Kern Dog said:
YES, the drums need to be on when bleeding the brakes.
Click to expand...

Maybe that's where I fucked up :BangHead:

When I had the MC out if the car I tried bench bleeding it by pressing the rod in and out, I was a pain in the *** so I went and purchased a syringe bleeder for it haha.

When bleeding the front brakes the pedal falls all the way to the floor when I release the nipple which is what it is supposed to do. I also bled the calipers before installing them on the car.

Tonight I literally used more than 1 large bottle of brake fluid trying to bleed the brakes. Luckily I bought 4 right?!
 
72bluNblu said:
They absolutely MUST be on if you plan on stepping on the pedal. You can bleed brakes without them, but only with a vacuum or pressure bleeder. If you step on the brake pedal without the drums on you can overextend the wheel cylinders, which sets the bleeding process back to zero. Also, that takes a ton of fluid, which is why you're not getting the calipers working right.
Click to expand...

Ah I see. Yes I tried bleeding them with a vacuum pump bleeder but it didnt seal very well to the nipple so wasnt holding pressure to suck the fluid out.

So tomorrow I will try again with the drums on and see if I can get better results. If so I will have the wife test drive the car to make sure it's safe for the rest of us to drive :rofl:
 
DentalDart said:
Maybe that's where I fucked up :BangHead:

When I had the MC out if the car I tried bench bleeding it by pressing the rod in and out, I was a pain in the *** so I went and purchased a syringe bleeder for it haha.

When bleeding the front brakes the pedal falls all the way to the floor when I release the nipple which is what it is supposed to do. I also bled the calipers before installing them on the car.

Tonight I literally used more than 1 large bottle of brake fluid trying to bleed the brakes. Luckily I bought 4 right?!
Click to expand...

Alright. Here is how you bench bleed the Master cylinder ON the car. First, level the master cylinder on the car. Jack it up in the back if you have to. Get the MC LEVEL. Now get someone inside who can FOLLOW instruction. Get them to depress the pedal down ONE TIME and hold it TIGHT. Now, loosen the rear line on the master cylinder. Let it drain fluid and air....or dead aliens or whatever, then close it. DO the same with the front. ALL THE WHILE your helper is holding the pedal hard. Make sure the pedal goes to the floor each time. DO NOT pump the pedal multiple times during the bench bleed. Only go down ONCE each time. After you tighten the second fitting each time, your helper can release the pedal. Then repeat until you get solid fluid out of the master cylinder. Done. From there, you can gravity bleed starting from the right rear, left rear, right front, left front. In that order. Then you should be getting somewhere.
 
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