Hard brake pedal 1961

[t-bob]

I have to push hard on my brakes to stop. Pedal is hard. My brakes are bled, new wheel cylinders, brakes are adjusted, lines are good, new master cylinder, newly rebuilt brake booster, linkage not binding. Master cylinder push rod adjusted. Good vacuum. What could be the problem?

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[74 Harley]

It really sounds like the booster is not working. Do you have a picture of the vacuum hose system?
Is this a new problem or did it have this problem when you got the car?

 

[t-bob]

It really sounds like the booster is not working. Do you have a picture of the vacuum hose system?
Is this a new problem or did it have this problem when you got the car?

It really sounds like the booster is not working. Do you have a picture of the vacuum hose system?
Is this a new problem or did it have this problem when you got the car?

This is my High School car I sold in 1974. I just found and purchased it in August last yr. When I drove it home it had a hard pedal. I had the booster rebuilt by Calif. Auto Rebuilders through Larry's Thunderbird Parts.. I called them about the still hard pedal and they are firm that it is ok. The pedal does go down slightly when I start the car.

 

[t-bob]

This is my High School car I sold in 1974. I just found and purchased it in August last yr. When I drove it home it had a hard pedal. I had the booster rebuilt by Calif. Auto Rebuilders through Larry's Thunderbird Parts.. I called them about the still hard pedal and they are firm that it is ok. The pedal does go down slightly when I start the car.

I just got off the phone with Calif Auto Rebuilders. They are going to recheck the booster as soon as I can ship it to them. Real nice people.

 

[74 Harley]

Ok, I am going out on a limb here as all my books and manuals are 800 miles away.
From the picture it appears that there is also another vacuum hose attached with the booster hose. I believe the booster should be on a dedicated port by itself.
Any other vacuum leaks will also cause your issue.
You may want to pull and plug all the lines except the booster and then try the brakes. It may save sending it back.

 

[t-bob]

Ok, I am going out on a limb here as all my books and manuals are 800 miles away.
From the picture it appears that there is also another vacuum hose attached with the booster hose. I believe the booster should be on a dedicated port by itself.
Any other vacuum leaks will also cause your issue.
You may want to pull and plug all the lines except the booster and then try the brakes. It may save sending it back.

I just removed it, but not too bad putting it back on to check this out. One vacuum hose goes from the engine manifold to the booster. The other vacuum hose on the same manifold t goes to the transmission vacuum diaphragm valve unit. The smaller hose on the booster goes through the passenger side firewall. So there is one extra line from the manfold t and one extra line off the booster. It is very possible you are correct. I may not have enough vacuum! I have to go to Northern MN for a couple days and when back I'll put it together and let you know. THANK YOU for your help. Tim

 

[74 Harley]

You are welcome Tim, hopefully all goes well.

 

[Mike McElroy]

You are welcome Tim, hopefully all goes well.

 

[Mike McElroy]

I just removed it, but not too bad putting it back on to check this out. One vacuum hose goes from the engine manifold to the booster. The other vacuum hose on the same manifold t goes to the transmission vacuum diaphragm valve unit. The smaller hose on the booster goes through the passenger side firewall. So there is one extra line from the manfold t and one extra line off the booster. It is very possible you are correct. I may not have enough vacuum! I have to go to Northern MN for a couple days and when back I'll put it together and let you know. THANK YOU for your help. Tim