Master cylinder to booster pushrod help
Thread Starter
Racer
Joined: Jul 2007
Posts: 269
Likes: 0
From: WV
Master cylinder to booster pushrod help
I have a 75 vette with power brakes. Since I purchased the car it has always had a low pedal but has stopped well and could lock up the brakes but just close to the floor. In the past I bled multiple times with no real change. I decided to tackle things and get it right. I have now replaced all lines, all hoses, both distribution blocks, the proportioning valve, and the master without a change at all. After some research I believe I may be missing a piece between the master and proportioning valve
This is the piece that goes between the master and the booster I believe there should be something that goes inside of it.
This is the hole where it appears a rod should go if I am right.
This is what the back of the master looks like.
So please help me let me know if I am missing something or just going crazy and where to find the parts before I go crazy
This is the piece that goes between the master and the booster I believe there should be something that goes inside of it.
This is the hole where it appears a rod should go if I am right.
This is what the back of the master looks like.
So please help me let me know if I am missing something or just going crazy and where to find the parts before I go crazy
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
This is the oem adjustable rod for a deep piston (75).
Your booster may have been changed with an aftermarket.
I'm not implying that it will not work, just that it's not original.
To test for full pedal, cap the ports on the master and with the engine off see how much free pedal you have.
Your booster may have been changed with an aftermarket.
I'm not implying that it will not work, just that it's not original.
To test for full pedal, cap the ports on the master and with the engine off see how much free pedal you have.
Thread Starter
Racer
Joined: Jul 2007
Posts: 269
Likes: 0
From: WV
I am a little confused since this is the first booster/master I have worked on. The rod that you show in the picture is that supposed to go where the black piece is in my picture one? I am just having a hard time visualizing it and figuring out what I need to get to make it work properly. I will have to check it tomorrow morning if I can find some plugs.
Thread Starter
Racer
Joined: Jul 2007
Posts: 269
Likes: 0
From: WV
Can anyone tell me if what I have is normal for a corvette or what I can try to change it to make it work properly.. I have been doing a lot of searching and reading and really believe this is my problem. I just do not know how to rectify it.. The threads with pictures all are too old to show pictures.
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
Your black piece is just a different type of push rod. Probably designed so that it, along with the master it came with can be used for both the early and late versions of the master cylinder.
The only part you should be concerned with is that there is no excess play between the black rod and the piston in the master cyl. That would result in more free play in the pedal and ultimately a lower pedal.
Doing the test I suggested will give you an idea of any lost pedal travel. You should have a hard pedal 3/8" from the top if everything is correct.
You could try a crude test by putting a nickle or dime on the end of the pushrod with scotch tape (carefull not to interfere with the seal) and hold the master against the booster. You should have a space between the two approx the thickness of the coin. Make sure the coin or spacer does not hit the circlip in the master.
The only part you should be concerned with is that there is no excess play between the black rod and the piston in the master cyl. That would result in more free play in the pedal and ultimately a lower pedal.
Doing the test I suggested will give you an idea of any lost pedal travel. You should have a hard pedal 3/8" from the top if everything is correct.
You could try a crude test by putting a nickle or dime on the end of the pushrod with scotch tape (carefull not to interfere with the seal) and hold the master against the booster. You should have a space between the two approx the thickness of the coin. Make sure the coin or spacer does not hit the circlip in the master.
