RYAN77

Guys im pulling my hair out i replaced all lines, prop valve, mastercylinder,wheel cylinder, calipers,rubber hosses etc all new, I cant get the rear brakes to bleed i bench bleed the master fine when i put it on car no fluid will come out rear port, i replaced the brake booster to, ive tried 3 master cylinders with no luck. Any sugestions?

Eric Anderson

I would start by bleeding fluid out of the lines at each fitting until I found the stoppage. Or did you try this and it won't come out of the master?

RYAN77

i cant even get fluid from master i cracked fitting and nothing, worked when bench bleeding and nothing on car, i even tried vacuum bleeding and i cant get anything?

Eric Anderson

When you bench bled the master did you use the fittings that go into the line ports or bleeder valves on the master itself? When you depress the pedal are you getting fluid from the front port but not the rear? Did the new booster you installed have an adjustable end where it attaches to the pedal assembly? Perhaps the rod is too short not allowing full action on the master.

RYAN77

i get fluid from front i bench blead it with the clear hoses, the booster cam with 2 rods one is shorter then the other the long on sticks out past the booster.

hamm36

My new booster came with two different rods on the master cylinder side. New master cylinder came with a bullet type plunger that went in the back of MS to match up to the new booster rod on MS side. I used the one that made the booster look the most like the one that was removed. I bench bled on the car , that way you know you got the rod length right. Good luck.

RYAN77

well the old booster is gone was not on car when i got it, the long rod sticks out about 1 1/2 where the short one is about a 1/4 past.

Eric Anderson

It sounds like your problem is all in the booster. I have bled the master on the car before but it should be done with the master level to make sure an air bubble doesn't get trapped in there as it is at an angle when mounted on the car. I have an old booster out of my 70 hanging in the garage I'll take a look at it, the long rod seems too long but you could give it shot.

RYAN77

yes its at an angle, should i shim it leval? what should i try next?

Eric Anderson

No when its mounted on the car it is supposed to be at an angle, the purpose of bench bleeding is so the master is level preventing an air bubble from getting trapped. I think your only problem is the rod that is in the booster now is too short and it is not fully depressing the master.

RYAN77

WELL THE GUY AT THE BOOSTER PLACE SAID I NEED A MASTER WITH A 1 1/8 BORE THAT MINE IS NOT DEEP ENOUGH AND I SHOULD USE THE LONGER ROD I TRIED AUTOZONE AND ADVANCE SAME AS THE 3 OTHERS IVE GOTTON ANY ONE HAVE A SUGESTION?

joe_padavano

Back to troubleshooting basics. Disconnect the outlet pipe from the rear of the proportioning valve. Pump the brakes. Does fluid come out? If yes, connect it and work your way back to each joint. If fluid does not come out, you have a problem with the proportioning valve. It's possible that the internal spool valve that triggers the BRAKE light has stuck at one end and blocking the outlet port. Is the BRAKE light on?

Eric Anderson

Hey Ryan, I checked my old booster and the rod projects 5/16" so you have yours set right for the origional type master. Did you try the longer rod? If all else fails you may have to buy a new master cyl. Where did you get the one you have? Did it come with the booster?

RYAN77

prop valve is new no fluid comes out back port on master when bolted on car works when bench bleeding

RYAN77

the master were from autozone ive tried three diferent ones. ive adjusted the pedal fork all the way out, all the way in, tried in the middle and nothing.

Eric Anderson

Did you try the rod that sticks out 1 1/2"? If you can't find the correct master locally or make the one you have work I know BAP sells them probably other resto houses as well.
I can't believe autozone wouldn't have them but I've gone in there more than once and the guy behind the counter stood there looking at me like I was speaking a foreign language.

RYAN77

im going to order the correct one from just power brakes looking at it i dont see how it will make a diference but the tech guy said it will he said the depth of the hole in the piston the rod goes into should be 1 1/8 i dont know ive never had a promblem like this im ready to swith to manual brakes what involved with that?

Eric Anderson

You don't wanna' do that. Once you get the right master on it you will be set. If these old cars didn't throw a curve ball at ya' every once in awhile it wouldn't be any fun.

Was it an M or NM 1521 master he was giving you? That would be the A-zone part number.

RYAN77

the latest one is a m1521 its the remanufactured one the other one i just returned was the new one

Eric Anderson

Is that place you're getting the new master from the same place you got the booster from? If so they should be able to give you the right setup. That A-zone part # is the one that shows on their web-site I dunno? Mabey that booster and master is some kind of matched setup?

RYAN77

booster is from just power brakes

hamm36

Try to get a MS with the insert that will make it flush at the back where the "short" rod from the booster will push it.
This is a good reason why I got the brake set-up in a bolt on kit. Don't pull your hair out just yet. Unless you need to get to work, or something?
There are several parts on my car that I had to send back at least once. Because it was wrong, or make them give me two of the same matching parts. Including the rotors from the kit.

RYAN77

what do you meen by insert are you saying there should be no dimple where the rod meets the piston, do you have a part number?

Eric Anderson

Thats good, once you get the right part from them you'll be good to go. Like hamm said leave the hair alone... it falls out fast enough on it's own

hamm36

Dimple will be there. Not smooth flush, the dimple will be there flush.
Eric is right, get the MS from the same place you got the booster.

Make sure the E-brake is working also, just in case. Man I drove mine back and forth in the back yard first, then out on the road. The more I drove the better it got. Spongy at first, but not dangerous.

My motor builder said this and it stuck like nothing else, "You can look around for parts to save a couple dollars, but look at the time it cost you to do it."

jcs933

I had a similar problem when I replaced the booster and master on my '70 Cutlass. The length of the pushrod (between the booster and master) is crucial. If it is too long by any distance, it preloads the piston in the master which move past and closes off the port timing hole in the master. The rear port timing hole will get closed off first. This is why you cannot bleed and why you did not get any fluid out of the rear outlet on the prop. valve. You must use the pushrod that comes with the booster. There cannot be any preload on the piston in the master when you mate it up to the booster. Hope that helps.

redoldsman

This is not going to solve the problem but it reminds me of a story from long ago. My wife and I began dating in 1965. She was a senior in high school and had a 1958 Vaxhaul station wagon her aunt and uncle had given her. Now I know a lot of you have never heard of a Vaxhaul but it was imported by Pontiac. Her dad had worked on the brakes and could only get a little pedal. I helped him and we bled the thing and still had very little brakes. Then it came to me one day, the master cylinder pushrod needed adjusting. After I adjusted it the brakes worked fine. I had not thought of this story for a long time. Sorry it does nothing to help fix your brakes. I just thought it was worth sharing.

RYAN77

im using the rod that came with the master should i shim the master

Eric Anderson

Is this the new master from the booster supplier? It should work right out of the box.

hamm36

This looks like a question. I would say, NO. No shims, get the right MS for the booster. Or get the right booster and MS for your car.
You can do it, I can tell.

RYAN77

well i figured it out i was using the old master cylinder gasket from the old booster and that was messing it up. I now get fluid ive blead the brakes but the brakes feel spongey