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Discussion Starter · #1 ·
I have just replaced much of the brake system on my '75 Z. Rebuilt calipers, new pads, new drums, new shoes, new wheel cylinders, braided brake lines, and master cylinder. I added the brake fluid and bled the system. Now I have no brakes. Pedal goes to the floor. I had a partner help with the bleed. When I went back to check everything, each wheel showed no sign of air in the line after 10 pumps of the brake. Is that enough to look at each wheel of the system? I'm pretty stumped and frustrated...
Thanks to all, GT75Z
 

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Did you bench bleed the master cylinder?

Did it build pressure while pumping to bleed the lines?


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Discussion Starter · #3 ·
I did not bleed the master cylinder. Never have had to do that before. Although I have never evacuated the system like I did this time. I guess I will try that. Can I do that after having filled the lines?
Some pressure built up while bleeding the lines and all the lines seemed to pump just fine, except for one, the front right wheel did not push the fluid through like the others did.

Thanks! GT75Z
 

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I did not bleed the master cylinder. Never have had to do that before. Although I have never evacuated the system like I did this time. I guess I will try that. Can I do that after having filled the lines?
Some pressure built up while bleeding the lines and all the lines seemed to pump just fine, except for one, the front right wheel did not push the fluid through like the others did.

Thanks! GT75Z
If you didn't bleed it, then that's definitely the problem.

Fill the system up with fluid and let it drain through. Once there is fluid in the system, begin your bleeding process. when bleeding, never let the master cylinder fluid reservoir go dry or you will need to start the process over.

It looks like you bled it now. How did you bleed it? I like having someone help me by pumping the brakes.
 

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I agree with mailnome, you probably just didn't get the bleeding done right.
but, can I ask where did you get your master cylinder from?
some of these aftermarket ones aren't all that good a parts. I got one from autozone one time and it didn't even work... I took it back and got an OEM unit from Napa. worked like a charm.


Bon
 

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Discussion Starter · #6 ·
The master cylinder is a Beck/Arnley from Rock Auto. It seems to be working fine. I started out trying to bleed it myself but I did not like that process so I got my wife to pump the brake as I opened and closed the bleeder. I am not sure of the process for bleeding the master cylinder. Do I need to start over from the beginning? The system has fluid throughout, can I now just try to bleed the master or do I start the whole process over again?
Thanks, GT75Z
 

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The master cylinder is a Beck/Arnley from Rock Auto. It seems to be working fine. I started out trying to bleed it myself but I did not like that process so I got my wife to pump the brake as I opened and closed the bleeder. I am not sure of the process for bleeding the master cylinder. Do I need to start over from the beginning? The system has fluid throughout, can I now just try to bleed the master or do I start the whole process over again?
Thanks, GT75Z
Connect two hoses to the two brake fluid outlets and route the hoses back into the fluid reservoir bowls. As you pump the brakes, bubbles will flow out of the bowls and be sure to keep topping the bowls off until there are no more bubbles.

THEN hook it back up to the car's brake lines and bleed the rest of the system which shouldn't take too long.
 

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Discussion Starter · #9 ·
Well I bleeded the Master I do believe. I couldn't find any clear tubing so I had to use black. I bled the master as per cats suggestions. Was getting no bubbles after numerous pumps so I reconnected the brake lines, bled each wheel and seemed to find air which I pumped out till we could pump no more. Still I have no brakes. With the engine not running, I have some resistance on the pedal but it will still go to the floor. With the engine running it goes straight to the floor. Thanks for any thoughts...
GT75Z
 

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Frustrating problem that I too had just 3 weeks ago -
I upgraded the front calipers to the larger Toyota 4x4 and replaced master cylinder while I was at it. However, I couldn't get a pedal no matter what I did. When I cracked open the bleed valve on either caliper, there was very little air and of significant importance, brake fluid only dribbled out - like an old man peeing...

So, not knowing what else to do, I put back the original front calipers - no joy. Next I turned my attention to the new master cylinder which was properly bench bleed, or so I thought... I bleed it again and this time I was able to push quite a bit more air out so that was one possible issue. The other possible issue was how my son was pushing the pedal. Turns out that his strokes / pumps were only half strokes / pumps. After a course correction with fuller pedal strokes, I could see air bubbles rising in the resorvior front brake cup of the master cylinder. My son then reported a fuller pedal feel and this time when I cracked open the bleed valve this time around, brake fluid and air shot across to the other side of the car- like an 8 year old boy pissing straight up 6 ft in the air...
Bottom line, there was a whole lot more air in my system than I imagined. In fact. I went through a full large bottle of brake fluid and started on the second one...
Another area to consider being that you have changed out so many items is to make sure all your connectors are tight tight tight... A good trick is to apply axle grease around each new line connector. This will identify any air leaks in your connections. Remove grease afterwards.
 

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I had the same problem. All new brake parts, pedal builds some pressure when the car isn’t running, but once it’s running the pedal goes to the floor. What ended up being my problem was that the rubber pad that goes on the back of the engagement rod (or whatever you call it) had fallen off inside the booster. The brake booster comes out pretty easily and without letting air into the system if you have enough room to move your master cylinder out of the way, then I was able to get it out by sticking it with a sewing needle and I super glued it back into the rod.
108705
108706
 

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Reaction disc is the correct term. I probably pumped two gallons of brake fluid through mine until I discovered this problem. Welcome to the club. I removed the booster took it apart and placed the disc back where it belonged. You'll see that you need to be careful with the booster or the disc will fall out of place again.

I had the same problem. All new brake parts, pedal builds some pressure when the car isn’t running, but once it’s running the pedal goes to the floor. What ended up being my problem was that the rubber pad that goes on the back of the engagement rod (or whatever you call it) had fallen off inside the booster. The brake booster comes out pretty easily and without letting air into the system if you have enough room to move your master cylinder out of the way, then I was able to get it out by sticking it with a sewing needle and I super glued it back into the rod.

View attachment 108705 View attachment 108706
 

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My take is that the OP is skipping steps. The master cylinder needs to be bled. He can buy a short piece of metric brake line at the parts store , cut it in 1/2 with a tube cutter and bend the lines to to curl back into the reservoir. He could also use the ends of the newly purchased line with clear tubing. Just leave a little metal tubing on the threaded part. Now, the tool will be in the tool box and available for any metric MC for the rest of your life. Note that the metric and ASE fittings are not interchangeable even if they bolt up. They will leak.

Every hardware store around me including Ace, Lowes, the little still-in-business indy all sell clear hose by the foot. Probably 1/8" will work.

Once the master is bled, try at the wheel cylinders. If it doesn't go easy, move back up to the next joint in the system. These are old technology and the repair process for brakes is well know but you can't skip steps unless you just happen to get lucky.
 

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My take is that the OP is skipping steps. The master cylinder needs to be bled. He can buy a short piece of metric brake line at the parts store , cut it in 1/2 with a tube cutter and bend the lines to to curl back into the reservoir. He could also use the ends of the newly purchased line with clear tubing. Just leave a little metal tubing on the threaded part. Now, the tool will be in the tool box and available for any metric MC for the rest of your life. Note that the metric and ASE fittings are not interchangeable even if they bolt up. They will leak.

Every hardware store around me including Ace, Lowes, the little still-in-business indy all sell clear hose by the foot. Probably 1/8" will work.

Once the master is bled, try at the wheel cylinders. If it doesn't go easy, move back up to the next joint in the system. These are old technology and the repair process for brakes is well know but you can't skip steps unless you just happen to get lucky.
Well said...
Oftentimes we get ahead of ourselves with troubleshooting in the hopes of attaining a quick fix and yes, sometimes we get lucky but more often than not we get frustrated and lose time and money in the process.
 

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I am guessing the Rock Auto mstr. cyl. was a re-built, yes? As were the front calipers?

If so, I suggest you can bleed 'till **** freezes over without success. To test the possibilities, disconnect the lines out of the mstr., one at a time, and using a suitable catch can, check the outflow when someone pumps the pedal. If both do not produce a strong stream, you've found your problem.

If you haven't yet returned your "core", I suggest you re-mount it and try again. I suspect this would answer all questions.

"Re-built" may well be the answer to that rt. front caliper as well

$.02 from the cheap seats.
 
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