I have a 1978 jeep cj-5 that I just picked up and I have been going through and narrowing down some things I need to do. One item on my list was the master cylinder was leaking into the tub on the floor, as well as over the top onto the headers.. so I order a master cylinder from advanced auto.. went to install it today, and the rod that attaches to the brake pedal, has a round piece attached to it.. when I put the new master cylinder on, and press the pedal, it pops the lock ring on the inside of the master cylinder. I compared my new and old cylinder and they are exactly the same. Probably the reason it leaked is previous owner tried to fix and ended up with the same issue I'm having.. it fits and lines up.. but when u slowly depress the pedal it only moves an inch.. if u press harder it pops past that lock ring and then has full pedal stroke.. upon releasing it pops back past the lock ring.. wrong part? I uninstalled and installed multiple times.. Anyone else have this issue.. car has no vacuum booster on it (don't know if it came with it or not)
78 cj-5 brake issue
- Thread starter Zam1787
- Start date
I replaced the master cyl on my CJ 5 several years back but I wasn't faced with this issue. Sounds like either the wrong rod or wrong master cyl. You could take your rod to the parts store and see what a new one looks like compaired to yours. Maybe it had power brakes at one time and the rod may be different.
I bought a caliper and had to grind some off the casting to get the wheel to fit over it. Your MC may be made by the same poor quality company.
I bought a caliper and had to grind some off the casting to get the wheel to fit over it. Your MC may be made by the same poor quality company.
Empty Pockets
New member
I can't remember which is which, but on one cylinder, the rod bore in the piston is deeper than the other. Power and standard brake MC's are not interchangeable. If I recall correctly, the PB master rod bore is shallower than the manual cylinder, although it may be the other way around.
