Master Cylinder Question -
LinkBack Thread Tools
post #1 of 5 Old 05-22-2013, 08:48 AM Thread Starter
Registered User
1979 CJ5 
Join Date: May 2012
Posts: 37
Master Cylinder Question

I have been having some issues with my brake system so I decided to rip out and start new. I have replaced all lines (brand new), new proportioning valve (brand new), replaced both wheel cylinders in the rear drum brake (each brand new), as well as installed new calipers on both front wheels (brand new). After all lines were bled and I have good flow and pressure to all four wheels it seems I still have an issue.

The only part I haven't replaced (yet) is the master cylinder and/or the booster. I bought an all-in-one power brake booster kit from Morris 4x4.

I have good braking, but I am experiencing two things that worry me. The first is that fluid is leaking out of the top of the cover of the master cylinder. The second is that when I press the brake pedal to stop, I have to put my foot underneath the pedal to bring the pedal back to its original position.

All of the above being said, I have a few questions. On this particular master cylinder, the larger reservoir is located in the front of the two chamber master (furthest away from the firewall). This is where I have the front brake line that goes to the proportioning valve. The smaller chamber (closest to the firewall) is where I have the line connected to the rear brakes.

Is this the correct set up? I was told that the front brake need to be connected to the reservoir closest to the firewall because this is where the 60/40 braking comes from. But how does that explain a two chamber system where both of the reservoir's could be the same size?

Any help is appreciated. I have another master on order to replace the one I have on there now, but am questioning if I have the lines connected to the right ports on the master cylinder.

leon1017 is offline  
Sponsored Links
post #2 of 5 Old 05-23-2013, 07:31 PM Thread Starter
Registered User
1979 CJ5 
Join Date: May 2012
Posts: 37
Anyone out there?
leon1017 is offline  
post #3 of 5 Old 05-24-2013, 09:18 PM
Registered User
1975 CJ5 
Join Date: Jan 2013
Posts: 606
I will try and check mine tomorrow, but best I can remember the front goes to the larger resovoir. Mine is opposite from yours. The larger one is toward the firewall. Also, my brake petal has a spring on it to bring it back to the place it should be after you release the petal. Mine is a '75 though and could be a different setup than yours. Good luck with the master cylinder. I had to order about three before I got the right one. I ended up having to modify the push rod to make it work in the end. I also have a '78 model and I will try and check it too.
bradleybrb is offline  
post #4 of 5 Old 05-25-2013, 12:16 AM
Registered User
1974 CJ5 
Join Date: Jul 2012
Location: Kennesaw
Posts: 131
Larger res goes to the front, which should be disk brakes, because the piston in the disk brake is larger diameter and therefore needs to more fluid to move the same distance. Also the res itself is not what moves the fluid, rather it is where the fluid is contained that replaces the fluid that gets pushed by the cylinder toward the brake piston. So the actuating distance for moving the fluid is greater for the front cylinder as compared to the back one. Not sure if that made sense, but i hope it helped.

As for your squirting issue the cylinder is probably rough around the top so you don't get a good seal, or it might be a tear in the seal or something like that.

hope that helped a little

my origional was a 74 same size res and i think my new one is an 81 but i switched because I added disk to the front
bligon64 is offline  
post #5 of 5 Old 05-28-2013, 08:07 AM
Registered User
1975 CJ5 
Join Date: Jan 2013
Posts: 606
Looks like bligon64 got you fixed up. I checked mine, but then due to computer issues couldn't post. Did you get your problems worked out?
bradleybrb is offline  

brakes , master cylinder

Quick Reply

Register Now

In order to be able to post messages on the forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome